3 link rear MJ coming soon

[BrettM]

So for various reasons I have decided to link the rear of my MJ. If you wonder about why I would do something as bass-ackwards as reversing the factory setup to front leafs/coils rear read THIS (http://www.pirate4x4.com/forum/showthread.php?t=140080 ), then ask any questions you have.

I would have liked to do a dual triangulated 4 link, but I have decided that I want to leave the gas-tank where it is under the driver's side of the bed, forward of the axle. This left me with 2 options, parallel 3 link w/ panhard, or triangulated 3 link offset to one side. After researching both, I have decided I do not want to mess with some of the uneven characteristics of the 3 link w/ panhard, so I will be doing an offset triangulated (wishbone) 3 link. I will also be losing about 4 inches off the wheelbase in the rear, bringing me down from 115" to 111" while still not interfering with the gas tank.

Here is a picture of mine underneath (older picture, ignore the exhaust and basically everything besides the frame, gas tank and axle):

http://img269.echo.cx/img269/6711/toyotaaxlein24qg.jpg (http://www.imageshack.us)

here is one done similarly, but mine would be on the other side:

http://img270.echo.cx/img270/5062/raker47as.jpg (http://www.imageshack.us)

Build materials

-By the nature of this system it will function in geometry exactly as though the wishbone was the full width of the frame and symetrical if the frame mount is relatively rigid. Therefore I will be making Delrin bushings for those two attachment points rather than Poly. This will attach to a crossmember which will just barely fit between the gas tank and cab. This presents the first question, what material for the crossmember? The three I am considering at the moment are (in order that I would like to use them) 1.25" .250 wall DOM, 1.5" .120 wall 4130 chromo, or 1.5" .250 wall DOM. This crossmember will span 40 inches without support.

-The upper wishbone will be made primarily from 1.75 .120 wall DOM with multiple gussets.

-Both lower links will run parallel to the frame and will be made of 2x2 .250 wall square tubing.

-Both ends of the lower links will be poly bushings, as will the axle end of the wishbone. Rather than use rod ends or cartridge joints (and for adjustability) I will be using a large threaded section to make these "twisty links". They will consiste of 1.25" B7 (chromo) all-thread with 12 tpi, threading into grade 8 coupler nuts, with a total of 20 threads of engagement. This type of link has been suffiecently proven in my mind by a guy named Brook Green from Alaska. He uses the same thing on his Chevy truggy (http://www.akfabshop.com/images/Laborday03/lbrdy_03%20076a.jpg) whereas his are 1.5" thread, however his Chevy weighs roughly twice as much as my MJ, has a 513 Caddy motor under the hood, and runs 46" tractor tires. He has been running "twisty links" for several years of serious abuse and when he recently took them apart he noticed no increase in slop.

-some reading on "twisty links": http://www.pirate4x4.com/forum/showthread.php?t=358084
http://www.pirate4x4.com/forum/showthread.php?t=282710
http://www.pirate4x4.com/forum/showthread.php?t=240839



-For coils I will be using stock XJ coils. My MJ is only 3600 pounds and heavily weighted to the front, so I'm hoping the soft rate on the XJ coils will be about right. They will be on adjustable mounts, so that if I need to cut the coils some to increase springrate I can easily adjust the ride-height back. 14" travel Bilstein 5125 shocks to go with.



Suspension Geometry

All these numbers are still approximations because I won't be back at my MJ for another couple days, though they should be fairly accurate based on measurments I've taken before and written down.

-Anti-squat looks to be coming in at 70%, some adjustability in the mounts would allow that to go up about 20% or down 10%.

-Roll center is at 28 inches. Sprung COG is (guessed) at 40.5, making overall COG at 34.5".

-Roll axis is tilted back (oversteer) 8 degrees. This is the only number I don't really like, but sort of a necessary evil of the triangulated 3 link.

-39" upper, 43" lowers.

-68% antisquat at 5" compression, 113% at 10" droop.

http://img282.echo.cx/img282/140/drawing4resize1ag.jpg (http://www.imageshack.us)

This is essentially what I'm looking at:

http://img283.echo.cx/img283/5179/3link0fn.jpg (http://www.imageshack.us)



Coil mounting

I am going to have the coils captured on both ends, and I think that along with a high roll-center and leaf springs up front will keep my MJ very stable. The coils will be mounted about 43" wide, directly under the frame rails.

The top mount will be this style:

http://img288.echo.cx/img288/1014/dsc012312xk.jpg (http://www.imageshack.us)

but on a threaded adjuster (same 1.25"-12 allthread) like this:

http://img269.echo.cx/img269/3630/progress001a9kh.jpg (http://www.imageshack.us)


The lower mount will have the coil feed through two small pieces of tube like this, and will have an internal bumpstop like an XJ coil front suspension:

http://img270.echo.cx/img270/6346/p10102835xi.jpg (http://www.imageshack.us)





Well, that's all I got for now. It all seems pretty clear in my head, but please give input anywhere you see room for improvement or problems you see

[BrettM]

Common, we finally got an advanced tech section and the best you guys can handle is notching tube and attaching radius arms? :flipoff2: (we need that smiley)

No input on suspension geometry? No input on material for the crossmember? I was also thinking of using square tubing for the crossmember since the bending force will be at a relatively predictable angle.

[Goatman]

Ahh, come awn. You expect us to take you seriously after you do leaf springs on the front? :)

You can get opinions to support any position you choose..........so we keep our own opinions. :D :D

I haven't read all that you posted, but from a quick look with the time I have, it looks like you pretty much have it figured out. Personally, I like panhard bars, but you already eliminated that possibility. Sure, in straight up and down axle cycling there is a slight side to side movement, but it effects little. When articulating, that doesn't happen, and I like how a panhard bar keeps things tracking straight. Panhard bars are very cool for articulation.

[BrettM]

I would think the leafs up front would make you take me more seriously because it shows that I am willing to think outside the XJ box :laugh3: besides, who does "mid-arms" anyway? everyone knows longarms are where it's at :D

I also have nothing against panhard bars, but the decision to not do a parallel 3-link came from the handling quirks of having the upper link offset to the passenger side. Ideally the upper arm would be on the driver's side to counter-act the torque from the engine and keep even weight on the rear tires, but having it to the passenger side accentuates the weight shift from engine torque. I did a bunch of research on this and there is even an equation to figure how far from center to the driver's side you should have the arm based on angles and gear ratio in the diff. This is still a minor consideration however because I've heard on the Pirate board that the effects are negligable, but it's hard to say if that statement is from experience.

"So move the gas tank" is the logical reply, but if I decide to go that route I will just do a dual triangulated 4 link.

[Goatman]

You have a good point there. It would be hard to determine the exact effect until you built it, which is a lot of work. It's also a lot of work to move the gas tank.

So, why do you want to switch from leaves in the rear? It works just fine for Fordyce and the 'Con, doesn't it? :)

[Ludakris]

jeez, looks like you have covered all your bases. I like that you incorporated the adjustable spring perch and the lower spring retainers. The only thing I notice is the (oversteer) that you mentioned.. but like I said, I think you have covered all your bases without actually testing it in real world...

[JeepFreak21]

"So move the gas tank" is the logical reply, but if I decide to go that route I will just do a dual triangulated 4 link.

So move the gas tank :D
Billy

[CRASH]

I was worried about a driver's side upper arm on the front of the URF three link. The fear was unfounded. It climbs like a dream.

PaulS talked extensively to Currie about their new rock rig. They have done it both ways, and have felt zero difference.

FWIW....YMMV

CRASH

I would think the leafs up front would make you take me more seriously because it shows that I am willing to think outside the XJ box :laugh3: besides, who does "mid-arms" anyway? everyone knows longarms are where it's at :D

I also have nothing against panhard bars, but the decision to not do a parallel 3-link came from the handling quirks of having the upper link offset to the passenger side. Ideally the upper arm would be on the driver's side to counter-act the torque from the engine and keep even weight on the rear tires, but having it to the passenger side accentuates the weight shift from engine torque. I did a bunch of research on this and there is even an equation to figure how far from center to the driver's side you should have the arm based on angles and gear ratio in the diff. This is still a minor consideration however because I've heard on the Pirate board that the effects are negligable, but it's hard to say if that statement is from experience.

"So move the gas tank" is the logical reply, but if I decide to go that route I will just do a dual triangulated 4 link.

[XJ_ranger]

no responces due to only members aloud to see the thread thinks I.

responces of "ooooh and ahhhhhh" would come from black usernames.

put an 8.8 in there and call it good...

[Ron4x4]

I would suggest getting a fuel cell and remove the gas tank or move the tank (or Cell) to behind the cab then making a four link. It would be a lot of work, but in the long run I think it would be worth it. Just my .02

[Jes]

I would suggest getting a fuel cell and remove the gas tank or move the tank (or Cell) to behind the cab then making a four link. It would be a lot of work, but in the long run I think it would be worth it. Just my .02

I actually agree with that.
What are you trying to accomplish by doing this? Seems like you're working around stuff to make it fit and compromising the design.
If I were going to go through all the trouble and expense I'd do something like Led did, just cut off everything from the cab back and start with a clean slate.
When are you going to relink the front? :)

[BrettM]

I actually agree with that.
What are you trying to accomplish by doing this? Seems like you're working around stuff to make it fit and compromising the design.
If I were going to go through all the trouble and expense I'd do something like Led did, just cut off everything from the cab back and start with a clean slate.
When are you going to relink the front? :)
What am I trying to accomplish?

That is a great question and something I should have addressed up front. One of the main things I want to deal with is axle wrap in the rear. I could add some leafs to the pack to deal with wrap, but my truck is so light in the back it wouldn't flex at all then. I could add a traction bar, but the way I see it, that's half-way to really linking it, and with far less control of geometry, so might as well just go all the way. Another reason is it should actually come out lighter than leafs, and I'll be able to chop more of the frame off the rear. I also (minorly) bent 2 MJ main leafs last season, and I don't feel like dealing with that any more.

I don't think I can do a fuel-cell for california smog reasons. I certainly have thought about moving my tank behind the rear axle or doing the same with an XJ tank. I really don't want to raise the tank since that's about 150 pounds of weight that is down real low right now, and I'm concerned that leaving it at the same height behind the axle would leave it too vulnerable.

(Jes, no plans in the foreseeable future to link the front back up, if I do it will probably be a couple years off until I can do it with a HP housing and probably links very much like yours)

CRASH, thanks for the input on the parallel 3-link w/ panhard... I'm still going back and forth in my mind on this one, and I'm starting to really think of just trying it out; the lower links and coils mounts would all stay if I decided to change it, so it would just be a matter of changing the upper link to a wishbone... hmmmmm....

[FarmerMatt]

All the smoggys care about is the gas cap. As long as all your canisters & everything else is there than there will be no questioning. The gas cap could go to nothing, but as long as it passes their little vent tester than you're cool...

[Paul S]

I was worried about a driver's side upper arm on the front of the URF three link. The fear was unfounded. It climbs like a dream.

PaulS talked extensively to Currie about their new rock rig. They have done it both ways, and have felt zero difference.

FWIW....YMMV

CRASH

Actually, John Currie said that he prefers a front driverside UCA.
I decided that he & the guys at URF had it wrong, I put mine on the PS :)

Paul

[Matt S.]

Fishboy living to his name! Going against the flow!


Heres a wet one! :kissyou:


Ok, back to it: My take is to either to a tried and true 3link or a dual triangulated 4 link. Messing around with other ideas work, but why go through the trouble? Honestly when I go to do mine, a 3link will probly be what goes in. A whole lot less math to get the geometry right, and it just works.

Think about what you are able to do, then just do it.

Matt

[AZXJ]

Brett,

My MJ gas tank fit nicely across the between the uniframe rails..
Like this only with a real mount.. (http://arizonaxj.com/photogallery/displayimage.php?album=51&pos=74)

since you still have the actual floor of the bed back there I'd cut a hole to fit the tank into and fab some brackets and straps to keep it secure.

The biggest problem I have seen so far with shortening the wheel base is the unirails get in the way.. Mine is at 117 inches and I would like 110.
After several contemplations with the tape measure I opted to just keep the unirails and leave the wheel base at 117. Eventually I will run 40's or larger so the added wheel base isn't much of a problem in my opinion...
Once the tank is moved a triangulated 4 link will fit nicely.. No track bars or pan hard bars to fool with.

only other input I have is, capturing coils is dangerious as well as premautrely wears out the coils.. I'd suggest leaving one end of the coil uncaptured.

Take it easy
DaveO

[BrettM]

captured coils are dangerous?! never heard that one before. I can understand how it would prematurely wear them, but with stock XJ coils I could care less; I posted on the Sierra chapter board that i'm looking for some stock XJ coils and within 24 hours I had offers of 4 pairs for free.

I know what you mean about the rails getting in the way... I'm not totally opposed to chopping the frame right in front of the coil mounts, but hopefully it doesn't come down to that.

[CRASH]

captured coils are dangerous?! never heard that one before. I can understand how it would prematurely wear them, but with stock XJ coils I could care less; I posted on the Sierra chapter board that i'm looking for some stock XJ coils and within 24 hours I had offers of 4 pairs for free.

I know what you mean about the rails getting in the way... I'm not totally opposed to chopping the frame right in front of the coil mounts, but hopefully it doesn't come down to that.


This project is gay unless you cut the frame at the cab.

Be one with the Sawz-All.

Embrace the tube bender.

Your aura will glow brightly.

CRASH

[AZXJ]

I have seen captured coils like you pictured launch out from under vehicles.
This would be my impression of unsafe.. Also, stock XJ or MJ coils will not give you the lift you have now... After playing with MJ, XJ, and TJ coils I went with a 3 inch lift XJ coil for the height I needed..

Keep up the Great work Brett.. your Rig is really taking shape...
I just wish I had time to finish mine... lol...

Crash, Be one with the Sawzall.... She's your friend......
Stay tunned to my next project... One fugly 94 XJ (http://arizonaxj.com/photogallery/thumbnails.php?album=62)

later
DaveO

[BrettM]

This project is gay unless you cut the frame at the cab.

Be one with the Sawz-All.

Embrace the tube bender.

Your aura will glow brightly.

CRASH
i know... i know... this project may get put off until the fall and then cut it at the cab...

arg

[Roxtar]

I have seen captured coils like you pictured launch out from under vehicles.
Am I missing something?
How would a captured coil leave the vehicle?
The word "captured" being part of the phrase and all.

[JeepFreak21]

I have seen captured coils like you pictured launch out from under vehicles.
This would be my impression of unsafe.. Also, stock XJ or MJ coils will not give you the lift you have now... After playing with MJ, XJ, and TJ coils I went with a 3 inch lift XJ coil for the height I needed..

Keep up the Great work Brett.. your Rig is really taking shape...
I just wish I had time to finish mine... lol...

Crash, Be one with the Sawzall.... She's your friend......
Stay tunned to my next project... One fugly 94 XJ (http://arizonaxj.com/photogallery/thumbnails.php?album=62)

later
DaveO


Just run a limit strap down the center of the coil of you're worried about it.
Billy

[JeepFreak21]

This project is gay unless you cut the frame at the cab.

Be one with the Sawz-All.

Embrace the tube bender.

Your aura will glow brightly.

CRASH

http://www.slicky.net/smilies/werd.gif It'd be so much cleaner!
Billy

[Paul S]

i know... i know... this project may get put off until the fall and then cut it at the cab...

arg

I think you'll regret doing anything less. I also don't see the point in doing all that work if you're not going to shorten the wheelbase to at least 105"

Paul

[Joe]

This project is gay unless you cut the frame at the cab.

Be one with the Sawz-All.

Embrace the tube bender.

Your aura will glow brightly.

CRASH


Use the force Brett.

[Kaczman]

I hate to be another sheep, but design your ideal suspension and make the Jeep fit around it. The gas tank and frame rails should be easy to deal with later.

-Jon

[CRASH]

I hate to be another sheep, but design your ideal suspension and make the Jeep fit around it. The gas tank and frame rails should be easy to deal with later.

-Jon

Embrace the sheep, Jon.

CRASH

[Roxtar]

Embrace the sheep, Jon.

CRASHWith velco gloves?
One SeanR is enough.

[BrettM]

I think you'll regret doing anything less. I also don't see the point in doing all that work if you're not going to shorten the wheelbase to at least 105"

Paul
this presents a new question; what would ideal wheelbase be? I would anticipate that my wheeling over the next few years will be average about 4 trips a year to Rubicon, 4 a year to Fordyce, 4 a year to Moonrocks, and 1 a year to JV.

I have found the current 115 to climb really well which I want to keep to a degree, and turn radius is rarely an issue since the rear is narrower and very flexy, but what has been an issue is vulnerability of the rear driveshaft.

I tend to think ~108 would be the ideal compromise of all those things, or even leave it at 115 and get a 2 piece rear driveshaft to better protect it.

[Matt S.]

I think anything over 110" is too much. No direct experience. But I wheel with alot of Toys and they have such a harder time. Climb good, but turn like trash. FarmerMatt mentioned to me that his 109" WB on the cat was too long. He is going to drop it to 105" with the new rear end.

When I do mine, 105" is where I plan on sitting.

[Kaczman]

I'm at 107.5" and am very happy. Long enough to climb well, but still managable in rock gardens.

-Jon

[Paul S]

this presents a new question; what would ideal wheelbase be? I would anticipate that my wheeling over the next few years will be average about 4 trips a year to Rubicon, 4 a year to Fordyce, 4 a year to Moonrocks, and 1 a year to JV.

I have found the current 115 to climb really well which I want to keep to a degree, and turn radius is rarely an issue since the rear is narrower and very flexy, but what has been an issue is vulnerability of the rear driveshaft.

I tend to think ~108 would be the ideal compromise of all those things, or even leave it at 115 and get a 2 piece rear driveshaft to better protect it.

For CA trails I think it would be hard to beat the stock XJ WB. I don't think it would hurt to go a little longer, but I don't think it would help either. I can't think of anywere on the 'Con or Fordyce where a short WB (even TJ length) is a problem, & I can only think of a few places on the Hammers that 101" feels short, but even those spots are doable.
On the other hand, I think it would be quite a bit more work getting around the Hammers with 35's & a 109" WB.

Paul

[CRASH]

For CA trails I think it would be hard to beat the stock XJ WB. I don't think it would hurt to go a little longer, but I don't think it would help either. I can't think of anywere on the 'Con or Fordyce where a short WB (even TJ length) is a problem, & I can only think of a few places on the Hammers that 101" feels short, but even those spots are doable.
On the other hand, I think it would be quite a bit more work getting around the Hammers with 35's & a 109" WB.

Paul

Unless you have a Camper Special.

CRASH

[Goatman]

Keep up the Great work Brett.. your Rig is really taking shape...
... lol...



i know... i know... this project may get put off until the fall and then cut it at the cab...

arg

I think anything over 110" is too much.

No direct experience.

When I do mine, 105" is where I plan on sitting.

I'll sure be glad when Brett and Scrappy actually have their rigs done. I get a kick out of reading all the technical advice that comes from a guy that runs leaf springs and another that drives a stock YJ. :moon:












:laugh: :laugh: :wave:

you know I love you guys...... :D

[BrettM]

I'll sure be glad when Brett and Scrappy actually have their rigs done.


Hey now! my rig is "done" in the sense that I had a ton of fun with it at MoonRocks last weekend :) And am going to take it to either Fordyce, Rubicon or Hell Hole for a day trip tomorrow :)

bring that fat-ass, CTM and hub breaking junk up here and lets do some wheelin :laugh3:

and speaking of never being "done" with a rig, aren't you getting ready to fit up some coilovers up front?

[magoo117]

This project is gay unless you cut the frame at the cab.

Be one with the Sawz-All.

Embrace the tube bender.

Your aura will glow brightly.

CRASH
like this???http://img.photobucket.com/albums/v616/magoo117/IMG_0473.jpg

[JeepFreak21]

like this???http://img.photobucket.com/albums/v616/magoo117/IMG_0473.jpg

http://www.slicky.net/smilies/cool.gif Billy

[Lincoln]

I get a kick out of reading all the technical advice that comes from a guy that runs leaf springs...

He's going to need those to get some stability back after he screws up the design in back. :D

[Jeff 98XJ WI]

like this???http://img.photobucket.com/albums/v616/magoo117/IMG_0473.jpg

Hey Magoo, how about a link to ALL the photos in this album? I'm very interested. Jeff

[Goatman]

Looks like it's nicely done. I want to tube out one of my MJ's one of these days, but I want a quasi flat bed so I can still have room for gear stowage. Don't know where you'd put your gear if you went camping in it.

[magoo117]

Looks like it's nicely done. I want to tube out one of my MJ's one of these days, but I want a quasi flat bed so I can still have room for gear stowage. Don't know where you'd put your gear if you went camping in it.
Yeah,there's not much room for storage but thats what friends are for!!!

[Goatman]

Yeah,there's not much room for storage but thats what friends are for!!!

:D :D

Yeah, they can have the extra weight...... :laugh:

[Jeff 98XJ WI]

Looks like it's nicely done. I want to tube out one of my MJ's one of these days, but I want a quasi flat bed so I can still have room for gear stowage. Don't know where you'd put your gear if you went camping in it.

Here is a possible plan of mine. :) I'm thinking of narrowing, shortening, and bobbing a MJ bed and then mounting it to a tubed out rear end. I'm thinking it would look kind of like a flareside rig. Just thinking at this point, but I also would like it to be a bit more streetable yet woods/rock worthy too. I know just moving to a rig that doesn't have the upper rear portion of the xj body will be a blessing for fitting places!!! :) Jeff

[magoo117]

Hey Magoo, how about a link to ALL the photos in this album? I'm very interested. Jeff
http://community.webshots.com/user/magoo11794

[magoo117]

:D :D

Yeah, they can have the extra weight...... :laugh:
Thats my thinkin' !!!

[magoo117]

Here is a possible plan of mine. :) I'm thinking of narrowing, shortening, and bobbing a MJ bed and then mounting it to a tubed out rear end. I'm thinking it would look kind of like a flareside rig. Just thinking at this point, but I also would like it to be a bit more streetable yet woods/rock worthy too. I know just moving to a rig that doesn't have the upper rear portion of the xj body will be a blessing for fitting places!!! :) Jeff
I was originally thinking about using the stock bed.I realized I would be cutting so much off it away it wouldnt be worth it.I am going to make side panels out of aluminum to cover it up a little.

[JeepFreak21]

Looks like it's nicely done. I want to tube out one of my MJ's one of these days, but I want a quasi flat bed so I can still have room for gear stowage. Don't know where you'd put your gear if you went camping in it.


Yeah, I've been trying to come up with a good way to tube the back end, but keep room for hear and be able to keep it dry! (Dry from water crossings and puddles, not from rain and snow.)
Billy

[AZXJ]

So how did I get thrown into that Goatman ??? WTF!!! :kissyou:




I'll sure be glad when Brett and Scrappy actually have their rigs done. I get a kick out of reading all the technical advice that comes from a guy that runs leaf springs and another that drives a stock YJ. :moon:












:laugh: :laugh: :wave:

you know I love you guys...... :D

[Matt S.]

I'll sure be glad when Brett and Scrappy actually have their rigs done. I get a kick out of reading all the technical advice that comes from a guy that runs leaf springs and another that drives a stock YJ. :moon:




i cant believe I missed this! been a while since I have had time to read.

Rich, who else you know that can beat a stock YJ like I do? huh?

[043500]

Brett...I finally got my (leaf front end) MJ on the trails. Here's where I put my fuel tank. For now it's still leafs in the rear...but I intend to follow your line and run a 3 link or a triangulated 4 link in the rear some time in the not too distant future. BTW the front leaves flex pretty darn well. It stuffs the front tires all the way up into the fenderwell and droops nicely as well.



http://img237.echo.cx/img237/5766/mj30021gy.jpg
Yeah it's a poser shot at my buddies used car lot. I put the tank inside the tool box. I have storage on top of the tank and down the sides. It only raised the tank to the equivalent of it's own height over stock and also moved it to the center and forward some.

[ChuckD]

i cant believe I missed this! been a while since I have had time to read.

Rich, who else you know that can beat a stock YJ like I do? huh?


All I know is your sister is going to beat the crap out of you if you take it to Bald again! :D

[gearwhine]

Yeah,there's not much room for storage but thats what friends are for!!!

Don't you dare come to me. The only thing I'll carry is your skateboard, that is, if you're cool enough to still own it.

[magoo117]

Yeah,I'll always have a skateboard handy,although I won't be using it for awhile...http://img.photobucket.com/albums/v616/magoo117/new020.jpg

[magoo117]

WOW!!!! sorry for that,I didnt realize how nasty that looks!!!!

[gearwhine]

Holy shit mitch! That thing is beautiful. If you need help finishing up the MJ in august, let me know.

[magoo117]

Hmmmm,August is go time for me.I still cant walk right now,doc says August.Get ahold of me when you get home.

[BrettM]

say goodbye to the leaf springs!

it has begun!

http://img375.imageshack.us/img375/9541/p10100874vz.jpg (http://imageshack.us)


I still have not decided between 3 link w/ panhard or wishbone 3 link.... I think I'll just flip a coin...

[XJ_ranger]

I think I'll just flip a coin...

i can actualy help with this part

my silver dolar came up with "heads"

[Dirk Pitt]

I realize you don't want to move the tank, but is that the only thing stopping you from cutting the frame off behind the cab "Led style?"

Just seems like leaving the bed frame would only be an intermediate step before the inevitable. You are eventually going to want to chop it.

No bender? No money? No time?

[davidt]

i would move the tank to the very back where you have that storage box. It really isn't that hard, I moved mine to the same spot. It was super easy...check it out
http://i5.photobucket.com/albums/y183/davetheladiesman/P9120030.jpg
As far as backhalving the sucker goes, if brett wants to go that route, that is great, but I like having the seat time personally ;)

[BrettM]

I flipped the coin and I'm doing a wishbone.

I've got a few of the brackets tacked in place, but I haven't had a day off work in 9 days, so not much has been done. Here's the axle positioned at full compression, just clearing the gas tank, and about 6" of uptravel.

http://img186.imageshack.us/img186/3637/p10100910vr.jpg (http://imageshack.us)

I'm still debating the length of the lowers, somewhere between 30 and 40 inches; the longer they are the less flex-steer, but the worse ground clearance...

[Jes]

Nice use of the masonry products.

[davidt]

whats your new wb going to be?

[xjj33p3r]

How about 35" lower arms? Seems like a good compromise.

[BrettM]

Nice use of the masonry products.

:confused1:


whats your new wb going to be?

109", the axle is about an inch away from the gas tank at full compression.

How about 35" lower arms? Seems like a good compromise.

Howdja figger dat 1 out? soundz lik sum compilcated math...

;) I think I'm settling on 36", and if I decide to redo it this winter, so be it.

[xjj33p3r]

Good luck on your project.

[XJ_ranger]

109", the axle is about an inch away from the gas tank at full compression.


full compression verticaly, but what about the right side drooped and the left side stuffed, accounting for the "flex steer"?





EDIT - nevermind - thought it out and that situation creates more clearance...


though when the drivers side starts to droop, it will move forward...

hmmm...

[BrettM]

full compression verticaly, but what about the right side drooped and the left side stuffed, accounting for the "flex steer"?





EDIT - nevermind - thought it out and that situation creates more clearance...


though when the drivers side starts to droop, it will move forward...

hmmm...
it's fine

[BrettM]

This project is gay unless you cut the frame at the cab.

Be one with the Sawz-All.

Embrace the tube bender.

Your aura will glow brightly.

CRASH

The Sawz-All came out again, not all the way to the cab... but enough to make Eagle light headed.

http://img310.imageshack.us/img310/5636/p10100945sj.jpg (http://imageshack.us)

http://img310.imageshack.us/img310/3185/p10100981ys.jpg (http://imageshack.us)

The only way to make the coils and shocks as far out as I want them was to get rid of the frame, so that's what I did. I will also be able to get the cargo space exactly how I want it this way.

[CRASH]

The Sawz-All came out again, not all the way to the cab... but enough to make Eagle light headed.

http://img310.imageshack.us/img310/5636/p10100945sj.jpg (http://imageshack.us)

http://img310.imageshack.us/img310/3185/p10100981ys.jpg (http://imageshack.us)

The only way to make the coils and shocks as far out as I want them was to get rid of the frame, so that's what I did. I will also be able to get the cargo space exactly how I want it this way.


Oh yeah, I see this getting done before JV on the 19th. :rolleyes:

[magoo117]

looks like the beers where flowing while the work was going on :cheers:

[Phil]

Oh yeah, I see this getting done before your test run on the 30th. :rolleyes:

Fixed. ;)

[BrettM]

Oh yeah, I see this getting done before JV on the 19th. :rolleyes:
you better believe it! there really isn't that much left to do. as Phil said, planning on a test run to Highlakes in less than 2 weeks. though I probably won't get to some of the cosmetic aspects until after JV.

[CRASH]

you better believe it! there really isn't that much left to do. as Phil said, planning on a test run to Highlakes in less than 2 weeks. though I probably won't get to some of the cosmetic aspects until after JV.


Have you ever worried about cosmetic aspects in the past?

[BrettM]

Have you ever worried about cosmetic aspects in the past?
depends on if you like flat black or not... I think she's beautiful :gag:

[BrettM]

it's coming together, and I'll be working on it all day Sunday and Monday.

here's how it sits now:

http://img483.imageshack.us/img483/8704/p10101077dn.jpg

still some to chop, and some to add...

(the cinder block and tool box are just holding the "rocket box" in place of where I'm going to attach it)

[JeepFreak21]

Geeze! That cinderblock is scary! You wouldn't catch me working under that thing!
Billy



















:D

[BrettM]

got the driveshaft back today and finished with a bunch of gusseting on the axle

wishbone is 28" long, lowers are 33" long, 11" verticle seperation at the axle, 8" at the frame. with my estimated CG the antisquat is 78%.

I decided not to do threaded coil mounts, instead the upper coil mount is on a piece of 2x2 tube that will be welded to the side of the new rear frame. I will be able to change ride-height in 2 minutes of grinding and 1 minute of welding.

I also got some Aerostar coils instead of the XJ coils. A lot of Toyota guys have used them in the past for rear link suspensions. The main reason is that they come with very simple, effective, coil retainers on both ends. Mounting them simply required welding a bolt onto a flat piece of plate. That's it.

still need to:

-tie new rear frame into exo
-compress and mount coils and shocks
-add bumpstops
-re-do brakelines
-re-do exhaust

SOON!!!

Here's how it sits now:
http://img421.imageshack.us/img421/8954/p10101117vn.jpg (http://imageshack.us)

http://img478.imageshack.us/img478/1275/p10101131km.jpg (http://imageshack.us)

[ArcticXJ]

I'm still debating the length of the lowers, somewhere between 30 and 40 inches; the longer they are the less flex-steer, but the worse ground clearance...
Not neccesarily true.

The flex steer is more dependent upon and attributable to the reciprocation of angles from upper to lower link geometry.

Uh... I mean... its not so much the lack of link length that causes the flex steer as it is the triangulation or the difference in overall length of the uppers/lowers in relation to each other. If your rear links are double-triangulated and the upper ' V ' and lower ' V ' share similar angles (in opposite direactions, of course) then that would all but eliminate the flex steer, with little regard to the length of the links.

This is just for rhetoric and discussion's sake however though, seeing as how youve already buttoned up your setup and are happy with it.

[BrettM]

Not neccesarily true.

The flex steer is more dependent upon and attributable to the reciprocation of angles from upper to lower link geometry.

Uh... I mean... its not so much the lack of link length that causes the flex steer as it is the triangulation or the difference in overall length of the uppers/lowers in relation to each other. If your rear links are double-triangulated and the upper ' V ' and lower ' V ' share similar angles (in opposite direactions, of course) then that would all but eliminate the flex steer, with little regard to the length of the links.

This is just for rhetoric and discussion's sake however though, seeing as how youve already buttoned up your setup and are happy with it.
i am fully aware of how flex steer is influenced by the roll axis and triangulation, but as stated from the very beginning, I've chosen to stick with parallel lowers, therefore flex steer IS directly dependent on link length (and static angle).

If your rear links are double-triangulated and the upper ' V ' and lower ' V ' share similar angles (in opposite direactions, of course) then that would all but eliminate the flex steer, with little regard to the length of the links.


that's actually not true. there are some cases it is, but you could easily build a dual-triangulated 4 link following those rules that still has a steep roll-axis and tons of flex steer.

[ArcticXJ]

Would you mind elaborating on that? Not questioning your experience, just trying to learn from those with more. I would assume in order to garner flex steer from a dual triangulated 4 link, yes you would have to have an insane roll axis set up. But for that to happen, wouldnt you practically have to mount the uppers behind the axle and lowers [i]in front[/] in order to generate a severe enough geometry? Also accounting for that difference in axis by the frame end points being skewed fore and aft of each other the same difference?

And yes, I realized that parallel lowers were the plan and the execution; thats why I mentioned it was simply for discussion's sake.

[BrettM]

Would you mind elaborating on that? Not questioning your experience, just trying to learn from those with more. I would assume in order to garner flex steer from a dual triangulated 4 link, yes you would have to have an insane roll axis set up. But for that to happen, wouldnt you practically have to mount the uppers behind the axle and lowers [i]in front[/] in order to generate a severe enough geometry? Also accounting for that difference in axis by the frame end points being skewed fore and aft of each other the same difference?

And yes, I realized that parallel lowers were the plan and the execution; thats why I mentioned it was simply for discussion's sake.
here is a quick example:

http://img455.imageshack.us/img455/1439/untitled9wv.jpg (http://imageshack.us)

thick blue is lowers, thin blue goes to their imaginary intersection point. uppers are red, same thing. the green is the roll axis, sloped significantly and will have a lot of flex steer.

[ArcticXJ]

Good ol' MS Paint. I think you hit the nail on the head of what I was trying to say in my last post about the uppers being BEHIND the axle at their mounting and the lowers being IN FRONT of it. That pic put it into words better.

I didnt figure that anyone building their own link suspension would be ignorant enough to try to build something that looked like that above. I guess I thought that a proper roll axis (or at least somewhat proper) was an implied detail. I'll still stand by the dual triangulation rule, this time though factoring in that maybe the roll axis isnt just a given in the discussion.

[ArcticXJ]

BTW... your uppers are shorther than your lowers. :D

[XJ_ranger]

BTW... your uppers are shorther than your lowers. :D

there is more than one?

:D

[HTeK]

still need to:

-tie new rear frame into exo
-compress and mount coils and shocks
-add bumpstops
-re-do brakelines
-re-do exhaust


It's been 16 hours. I assume your done... right? :dunce:

Looking good. I can't wait to see it perform.

-jm

[BrettM]

It's been 16 hours. I assume your done... right? :dunce:

Looking good. I can't wait to see it perform.

-jm
I'm on my lunch hour now, just picked up some steel. has anyone ever seen two 21 foot sticks of steel in a Honda Accord? I have :D

[BrettM]

still need to:

-tie new rear frame into exo
-compress and mount coils and shocks
-add bumpstops
-re-do brakelines
-re-do exhaust

did the exhaust, exo tie in, and coils. In the following picture the weight is on the rear axle and coils, this was a height check, I need to move the coil mounts up about 2 inches.

http://img491.imageshack.us/img491/5499/p10101171vg.jpg (http://imageshack.us)

The exo is welded to 3 spots under each front fender and the whole length of the pinch seam/rain gutter. This should tie it into the uni-body structure very well. There will be an X or \ added behind the cab. Probably next summer the roof will get chopped out and some more tube up top. I think the structure now will do very well for sliding and flopping.

I still need to add door bars and more tube to the flat-bed. I'm debating the height and angle of the door bars; I want good protection but don't want it to be too much a PITA to get in and out... I'm thinking I will put it right here, any input? any reason to make the bar higher?

http://img494.imageshack.us/img494/2122/p10101180am.jpg (http://imageshack.us)

http://img494.imageshack.us/img494/4952/pdrm06937iv.jpg (http://imageshack.us)

[davidt]

are you planning on plating the frame rails? Looking good! How much tube will you use in the exo, just the two sticks?

[BrettM]

are you planning on plating the frame rails? Looking good! How much tube will you use in the exo, just the two sticks?
not gonna plate the frame rails at this point, the unibody is plenty stiff, especially with the tube work now, and I haven't had problems with the rails denting.

what you see there is about 40 feet. this week I will be adding another 10 or so on the flatbed and 12-15 on the door bars. then about 5 feet for an \ or 10 for an X behind the cab, though that may not get done til after JV.

[Dirk Pitt]

Are you planning to tie the top of the coil mounts into the cage?

[JeepFreak21]

http://img491.imageshack.us/img491/5499/p10101171vg.jpg (http://imageshack.us)


Is the yellowtop dead? It looks like it should be shooting sparks in this shot.
Billy

[BrettM]

Are you planning to tie the top of the coil mounts into the cage?
the square tube will be cut down a good 8-10 inches and gusseted much more to the flatbed, which will be tied into the cage even more than shown now.

[BrettM]

Is the yellowtop dead? It looks like it should be shooting sparks in this shot.
Billy
it's about 2 inches from the cab. I need to reroute my batter cables around the wishbone, so I just hooked the battery up there so I could start it and hear the new exhaust.

[BrettM]

shaved the Toy diff tonight, gotta love the clearance of only 4 3/8 inches hanging down from axle center line, and with a perfectly smooth bottom. Not much tech involved...

CUT:
http://img381.imageshack.us/img381/5817/p10101198jx.jpg (http://imageshack.us)

MAKE PLATE:
http://img381.imageshack.us/img381/669/p10101208sz.jpg (http://imageshack.us)

WELD and ENJOY!
http://img381.imageshack.us/img381/7494/p10101256ou.jpg (http://imageshack.us)

[davidt]

what thickness plat did you use for the shave brett? How much did you take off? Another toyota axle question, will a dana 44 yoke bolt in to a toyota axle housing?

[BrettM]

1/4" plate, the housing is 3/16. the higher your pinion is pointing the more you can gain with a shave, my pinion is pretty high at 23 degrees and I'd guess I gained very close to an inch. a D44 yoke won't bolt up, Toyotas have flat flanges and I got a flange to bolt up that takes a 1310 (factory Jeep) joint.

[davidt]

got pics of the flange?

[BrettM]

got pics of the flange?
best pic i could find:

http://img380.imageshack.us/img380/7410/p81407633ks.jpg (http://imageshack.us)

[BrettM]

here's a better one:

http://img380.imageshack.us/img380/8889/img03358ni.jpg (http://imageshack.us)

[ROCKREADYXJ]

did you use AR plate on the diff?

[xjj33p3r]

Any updates, Brett? Any pics of it holding itself together?

[BrettM]

i drove it around the other day. drove it down the street to Bent and Twisted and put it on their ramp. flexes great, but not absurdly. puts power to the ground so nice. no noticeable lift or rise or hard acceleration even with shocks off.

I'm thinking the next pictures I post might just be JV... we'll see...

[Ramsey]

Ya damn tease!

[xjj33p3r]

Post up just a glimse at least.

[MJ_Chubs]

Updates?

[JeepFreak21]

Updates?

http://www.naxja.org/forum/showthread.php?t=69962
Billy

[MJ_Chubs]

I was thinking more about pics of the completed 3-link....

[BrettM]

Post up just a glimse at least.


a glimpse? how's this? :laugh3:

http://img190.imageshack.us/img190/6711/p10101344bl.jpg (http://imageshack.us)

[xjj33p3r]

a glimpse? how's this? :laugh3:

http://img190.imageshack.us/img190/6711/p10101344bl.jpg (http://imageshack.us)
Hate you. :wave:

[davidt]

lookin good brett, can't wait to see the finished pics! How many sticks of tube did you end up using?

[BrettM]

between the cage and the bed, I bought 3.5 sticks (20-21ft), messed up a bend or two, and probably used a total of 50-55 feet.

[BrettM]

the 3 link, cage, and tube-bed worked GREAT in JV. Anti-squat was perfect as far as I could tell, flex-steer seemed to be a non-issue, and it was very stable off camber.

here's a picture from the lakebed, there are a few more posted in some of the JV threads, and I should be getting a bunch from Scrappy (my passenger) later this week.

http://img517.echo.cx/img517/9739/p10101424kq.md.jpg

[JeepFreak21]

the 3 link, cage, and tube-bed worked GREAT in JV. Anti-squat was perfect as far as I could tell, flex-steer seemed to be a non-issue, and it was very stable off camber.

here's a picture from the lakebed, there are a few more posted in some of the JV threads, and I should be getting a bunch from Scrappy (my passenger) later this week.

http://img517.echo.cx/img517/9739/p10101424kq.md.jpg

You drove it down there, right? How was that? Besides loud :laugh3:
Billy

[BrettM]

You drove it down there, right? How was that? Besides loud :laugh3:
Billy
loud and cold. the noise didn't bother me until it was my rear diff making the noise, it got me home but I think it's toast. the cold was bearable with a bunch of snowboard gear, it's just a good thing it didn't rain or snow.

[davidt]

Come awn, lets see some more pictures, we were all patient, now lets see some better pictures :P

[BrettM]

Come awn, lets see some more pictures, we were all patient, now lets see some better pictures :P
there are a few more posted in some of the JV threads, and I should be getting a bunch from Scrappy (my passenger) later this week