Project Scope Creep (alfred): Rear Axle Swap turned into Shackles&Relocation Brackets

Project Scope Creep (alfred): Rear Axle Swap turned into Shackles&Relocation Brackets

Preface: This probably old hat to the experienced crowd here. For those who don’t want to be bored with the details, if you skip to the end I could appreciate some advice regarding the driveshaft angle, the speedometer sensor plug and shock absorbers. Thank you.

I thought the Thanksgiving weekend would be a good time to tear into what I hoped would be a quick project: Swap out my 3.07 geared 8.25 rear for a 4.10 geared 8.25. Should be a simple, straight up R&R type job. Right?


Well, just about exactly one month later I am finally able to drive my XJ around the block again. So much for my hopes. Oh well. False hope is still hope. But I did learn a couple of things in the process. Largely about what doesn’t work, but hey, that is a start, right?


3.07 gearing is pretty pathetic. And I didn’t get lucky enough to have my ’96 come with a 29 spline axle. A Dana 44 would be nice, but they don’t seem to grow on trees. However, I found a free Chrysler 8.25 on C/L, got a 29 spline factory Trac-Loc carrier from a fellow member for the price of a couple six packs of beer, and a pair of Ten Factory 29 spline shafts were obtained from another member for about half the price of new. That seemed like a good starting point for an upgrade.


I dropped off the parts at a local shop and had them provide the gears and full bearing kit. I also gave them an Iron Rock Offroad U-bolt yoke and a crush sleeve eliminator. When I picked up the axle they told me they chose not to use the crush sleeve eliminator because it did not register properly on the lands and they thought it would cut through the shims. I was not happy about this. I wish they would have called me at the time they found the problem. I could have turned a new sleeve of my own to whatever dimensions they wanted. Oh well. Next time.


The axle got wire brushed with an angle grinder, primed and painted.


The free axle came with a box of brake parts, both for it and for the previous owner’s replacement axle (I think a D44—certainly not another Chrysler 8.25). It was a mixed up mess, and the brake shoes and drums were soaked with gear oil. I decided to simply order all new brake components. Slave cylinders, spring kit, shoes and drums were all ordered.


Additionally, for some reason, the new axle was missing the brake lines, so I ordered a replacement set of lines from Fine Lines and a YJ flex line to deal with a previous owners solution, i.e. to simply remove the hard line from its bracket and just let it hang in free space. Yeah, that is a long term solution. :looney:



I figured I should be good to go.


[FONT=&quot]Friday morning, after Thanksgiving I tore into things. Just getting into the job and then this happened:

[/FONT] Well, phooey. I hadn’t planned on needing new U-bolts. Yes. My mistake. I now know better. One thing learned.
The nice thing about Black Friday is that pretty much all local retail is open. I would have thought it would be no problem to run out and pick up another set of U-bolts, but the only place that admitted to having anything in stock for an 8.25 was Napa, and with them it was “Bring in what you have and we will try to match it.”
Well, they could match the diameter (for the axle tube), but not the length. What they had to offer was right about the length at which that one side snapped off.
Okay, fine. I had been wanting to ditch this stack of blocks and shims ever since I bought the Cherokee. It was time change this out to something better.
[FONT=&quot]For some time I had been looking for a leaf spring pack that would net me 3” or so of lift, then I saw this thread about combining shackle relocation brackets and longer shackles to yield the same effect

http://www.naxja.org/forum/showthread.php?t=1134237


[/FONT] I have seen a number of threads and comments bemoaning the pleasures of dealing with the factory hardware for the leaf spring mounts. I already liked the idea of switching over to HD Offroad Engineering’s Shackle Relocation Brackets. Getting a bit of lift that way sounded like good sense to me.


Additionally, I had seen Boostwerks’ Comp Shackles thread in the vendors section and really liked the concept.



Relocation Brackets and Shackles had both been ordered and were on hand. Parts just weren’t quite prepped though.


Even for just a rattle can paint job I hate leaving hard corners. They don’t paint well and they do wonders to my knuckles when I find them the hard way. I went over everything with a file before giving things a quick sanding, priming and paint job. Even the new U-bolts needed to be painted (Napa’s U-bolts are bare, not zinc plated). That slowed progress down for most of a day. But I did have time to pull the rear bumper and hit the OEM shackle bolts with Kroil. And say a prayer that those bolts would come out gracefully.


The next day I got to move forward from where I was when the U-bolt snapped. The old axle was supported in place on three cheap mover’s dollies from Harbor Freight (I decided my back was more worth the $30 investment. That is a decision I would not have made when I was in my twenties.)

The new axle was then swapped with the old on the dollies, keeping the same arrangement so that things could slide into place gracefully.

Some new brake lines got installed on the axle at this point. I didn’t want to put them on earlier for fear of mangling them while moving things around, but figured there was less risk now that the axle was on dollies and it would be easier now than it would be once the axle was in place.


Previously, in order to compensate for the bit of lift from the blocks, someone decided to remove the hard line from its support bracket and allow for some extra freedom of movement:

I can just imagine the surprise problem when the hard line finally cracks. I had already ordered a hose for a ’90-’95 YJ to take care of that little detail.

The new axle did not come with the old hard lines, so I ordered a new set of those from Fine Lines.

And then I also needed to get the exhaust out of the way since I was going to have to access the hardware for the receiver. I had anticipated needing to do this someday. When I redid my exhaust system I flanged my muffler/tailpipe joint. That was a big help.

Finally it was time to go after those evil bolts. Kroil, prayer and a life without salted roads makes a difference. No problem at all getting those bolts out. They hardly even looked bad.

And the pockets looked fine too.

The shackle relocation brackets went in without any fuss. They are a nice snug fit, and a few blows from a mallet helped seat them. Pretty much exactly what I want in a fit.


I understand the ’97 and up XJs have something different going on at the very back which requires that the one corner be notched out. I had to do something to make up for that on my ’96 because my receiver needs that support there. I found a stack of three 7/16” washers was a pretty close match to the ¼” plate.

Then I mounted up the channels. I was not that keen on how little threads there are for the bolts. I like to see a couple of threads past the nut. That is not the only standard though. Here is a summary of the subject if someone wants to delve into it : http://www.portlandbolt.com/technical/faqs/recommendation-on-thread-engagement/


It seems plenty of folks are running these without any problems, so I went ahead with it like this:

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Then came the installation of the Comp Shackles. In theory they will work with these relocation brackets. In practice, well, there are some limitations. The nuts/bolts which mount the relocation channels interfere with the Ballistic joints.





I could run using the holes at the very ends, or I could turn the channels around and using the slots I could use one of the center holes. It looked like the sweet spot was going to be right where the front nut/bolt was located. Good old Mr. Murphy. He always shows up to lend a hand.




My first thought was to try to come up with some deeper channels. That would give me a little more lift and provide clearance. I even called Brian to inquire about having them made. That sounded like it was going to be more trouble on his end and more expense on my end than either of us really wanted to incur. Among other options, Brian mentioned welding. I decided that was my best choice, but rather than try to get all the paint off of this set I simply ordered a second set of brackets. It is not a weekend project anymore.


But that gave me time to source some hardware that I had not been planning on needing when I first started this swap.


New factory bolts to replace the potentially evil ones:




New receiver mounting bolts because the old ones did not look particularly healthy:




New shackle mounting bolts because 4” is not quite long enough for this combination:




And this also gave me time to refine my trailer wiring situation. I did some cleaning up of the work of a P.O. when I did my tail lights, but I had run the wiring through a grommet in the bumper, and that meant that the bumper was tethered to the body. So I removed that harness, made a bracket and set things up so that in the future the bumper can be removed and separated from the wiring.




And





And skipping ahead to the end:



Once the new shackle relocation brackets arrived I set to work on them. First step was to fill in the missing corners so that I would not have to keep track of a stack of washers.




If someone is going to weld these pieces together I highly recommend a bolt to hold them together while welding. Among other reasons, that way you won’t mix the wrong pieces. It would be possible to assemble these pieces such that the bolt holes would not line up. An assembly bolt prevents that.




Welded:




Painted:




And I decided to measure and pre-drill the now missing holes for the end of the receiver. Reason being, I did not want to install these pieces to mark them and then remove, drill and reinstall yet again knowing that I was scraping off more and more of the paint each time. Marking the pieces before painting would have been ideal, but I have been trying to keep the Jeep at least looking like a functional vehicle for the sake of improved neighborhood relations. So I measured and crossed my fingers.




And things only halfway lined up:

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

A bit of work with a rotary file in a Dremel and a final clean up with a 15/32” drill bit got me the holes I needed.




Second set of brackets went in, mounted and then the shackles. I would not have thought the welding I did would have closed the channel at all. If anything I would have thought it would have pulled it further open. But I had about 0.030” of interference on one side. And those channels are stout. After repeated efforts at trying to persuade the last washer into place with a hammer, and then a bigger hammer, I finally wised up and went looking for another solution. A bit of 3/8” allthread and some hardware made a convenient spreader.





Finally I had my shackles where I wanted them:




At full droop:




At ride height:

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Now it was time to figure out how to deal with all this extra droop.


Even though I had not gotten things together properly with the first set of brackets I did get a good sense of what I was up against and I had ordered new e-brake lines. To be specific, two passenger side YJ e-brake cables:




A write up on this can be found here:
http://www.yuccaman.com/jeep/dana44.html#ebrake


I am going ahead and adding my own details though. It seems half the time when I find a link the link is either dead, or the pictures are gone. Redundancy is resilient.


I didn’t mind needing to cut this:




Nor did I mind losing this piece of fine craftsmanship:




But dang those clips are pain to get to release. I thought about ordering a tool, but this job already went above the expected budget. There had to be a simple answer for this. And I found it: A remnant of ½” copper, a tubing cutter and some judicious deburring of the inside. Don’t deburr it all the way to flush, at least not to start with. There is a sweet spot in there, and it may vary depending on the thickness of the rust layer on your particular application, but once you find it this is much easier than trying to use a screwdriver to depress all three prongs at once:




Here is the job in a nutshell: Cut off three inches of the original threaded rod (I used a Dremel), replace that with 5” of M8-1.25 allthread (it would be nice if you can find a plated version) using a couple of M8 nuts and an M8 coupler. Assemble with loctite.


Materials:




Assembled:




Another detail was the fiberglass insulation for above the muffler. The new lines did not come with this. My old insulation was not great, but I went ahead and cut it off to reuse it anyway. I attached it by wrapping it with aluminum duct tape (not the cheap, common duct tape, but the good stuff that sticks like crazy and forms to just about anything).




And




In the aforementioned write-up the author did not find any use for the brackets which came on the YJ lines, so he cut them off. I don’t know how much variation there is over the years, but on my ’96 there are some available holes on the seat belt mount on the driver’s side that looked like they had some potential. I got some M6-1 x 16mm bolts with washers and nylock nuts and was able to mount things up to my satisfaction, crossing the lines.




And




This arrangement seems fine at ride height and at full droop. I don’t have any tension to speak of on the brackets. Hopefully this will work out well long term. I was able to drop in one bolt from the top, but there was not enough clearance to do that on the other hole, hence the nut held to the wrench with tape trick (no room for fingers either up there).

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Reconnecting the exhaust showed a couple of minor interference details. First up was the hanger clamp right up against the leaf springs. This was not an issue when the springs were up higher, but in their new, lower position this was sub-optimal:




That was an easy fix though. I simply reversed the clamp.




This was not quite as simple a fix:




I wanted to ignore it, but upon start-up it immediately made its presence known. I will have to come back and revisit this later, but a Dremel got me this as a means to get by for now:




When I open all this up again for my gas tank skid I will have to drop that bracket and re-contour and repaint that section.


Next up was the driveshaft. The geometry of the rear suspension is such that the distance between the T-case and the pinion decreases with droop. The previous lift of stacked blocks had already pushed the limits on driveshaft length (the yoke could occasionally contact the T-case). With this new geometry the shaft was too long to even install at ride height. No question it had to be shortened. But by how much? I could not find any charts that specify how to measure for this kind of external slip yoke. Nor could the guys at the local driveshaft shop give me anything definitive.


The output splines on the T-case start 1” away from a shoulder, so I decided to operate with that inch as my buffer and set things up so that I had full engagement at ride height and the full inch available for droop travel. That gave me these numbers for U-joint C-C measurements:


At ride height: 29 ¾”


At full droop: 29”


At as much compression as I could manage: 30 ¼”


My compression number was obtained by disconnecting the shackles and then jacking the axle up as far as I could until I was lifting the body off the stands. I expect there will be a bit more travel, but I don’t expect the numbers to be dramatically different. As it stands I am willing to operate on the idea that I will have ¾” of driveshaft compression at full suspension droop and ¾” of driveshaft expansion at full suspension compression.


The shaft measured 30 ¾” to start and I had it shortened to 29 ¾”. Cut & weld, straighten and balance was $140.


That done, I still may have to go back and redo the driveshaft situation because of the new pinion angle. By the book I should be running a double cardan up at the T-case. My pinion currently points directly at the T-case. There is virtually no angle on that joint. At the T-case there is a bit of an angle, but not dramatic. How much of a problem is this likely to be? And what kind of failure can I expect? If it means I am going to wear out U-joints in 50,000 miles rather than 75,000 miles, well, no big deal. If it means the T-case U-joint will suddenly grenade and take out the backs of those in the front seats and the legs of those in the back seats, well, that might require some more careful consideration of the situation. Any experienced input would be appreciated, extra credibility given to those who have been placed in wheelchairs by exploding U-joints.


Here is how it currently sits:




And:

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

I kept putting off the brakes until last. Drum brakes are just an annoying juggling act with springs. No big deal, and I have been doing them for several decades. There shouldn’t be any issue here. Buy parts for the application. Assemble parts. Done. Yeah. Right.



I bought new slave cylinders, springs/hardware, shoes and drums from Rock Auto. All looked fine and all went together fine until I attempted to put on the new drums. Not going in. No way, no how.


I could get the drums started with the shoes angled inward, but that would only allow things to go so far.




And yes, I had the adjusters all the way in, the parking brake off and there was no pressure from the slave cylinders (line not even connected—didn’t want to accidentally press the brake pedal and blow out the little pistons. Don’t ask me how I know about this particular mistake.).



So I got to thinking, maybe the drums are not turned far enough, or maybe the shoes are slightly too thick.


I had the old drums that came with the free axle and tried installing them. No go.


I then decided to see about having the old drums turned. Yes, they still had enough material in them to turn them. I had to wait most of a day because they were busy. Finished product was within 1 mm of minimum diameter.



Well, I got those on, but darn they were stiff. One side had to be driven on with a mallet.


With the rear on jack stands I started it up and put it in gear and let it run for a couple of minutes, but that didn’t seem to be reducing any particular high spots and suddenly solving the problem.


I am thinking those shoes are oversized.

I did some research online and found a handful of potential solutions. The ideal answer is re-arcing, but good luck finding someone who can do that. OSHA shut that down sometime in the ‘70s. I found some discussion of lining a drum with sandpaper and using that to reduce the shoes, but that sounds like a painful way to waste a day. I found some folks solved this problem by grinding back their spreader bars and adjusters. I didn’t really care for that idea, largely because the spreader bars were one of the few brake pieces I had to reuse out of the old hardware. I don’t know what it takes to find new spreader bars, so I would prefer not to start messing those up.


However, that did give me some food for thought. Since the shoes are the source of my problem and the most likely solution would be to take them back and get another set (except that purchased these online and shipping would kill any savings), and the shoes are the consumable in this picture…I went to town on the shoes with a file. It really wasn’t much work with a file. The work was in removing the shoes and reinstalling them yet again. But that solved the problem.


I suspect the problem is cheap chi-com manufacturing not putting any effort into maintaining their stamping dies. Take a look at this picture and notice how far from square that profile is:




In a perfect world that angle which is visible at the top of that circled section should be a ninety degree angle. But stamped parts don’t work that way. One side will be crisp, but the other side is pillowed. Look at most any stamped washer and you can see this effect, but not generally so dramatically. This represents some pretty sloppy tolerances.


So I filed down the three inside contact areas on my shoes. This would be the places where the adjusters, spreader bars and top rests (round post) are located. I didn’t worry about the slave cylinders because I figure that one pretty much resolves itself. All I did was file these places to the point that I got a full contact pattern square across the stamping. IOW, I took out that angle. I went from this:




To this:




That solved the problem. It took me much longer to find the solution than it did to execute it. Hopefully this will help someone else out down the line. I doubt the chi-coms are going to substantially alter their practices.


At this point, the only thing left to do was to change out the speedometer gear to match the new gears. Thanks to ThatGrimmJeeper for this chart:




Thread here:
http://www.naxja.org/forum/showthread.php?t=1135317

The important thing to note here is to match up the new gear with the numbers on the side of the sensor housing.


I also need to figure out who makes this plug:




Someone wasn’t particularly gentle with mine. I would rather replace the housing than splice the wires. I just need to know what tools are needed to take those housings apart and release the pins. I have the tools to do it on Weatherpak plugs, but this is not the same. If anyone knows the right keywords for searching out the tools for this plug I would appreciate it.


And how could I forget shock absorbers? Oh well, I will leave them here at the end in hopes I can get some suggestions on the best solutions for this detail as it is probably the most pressing item to resolve. My shock absorbers are now much too short. By about four inches on the left side, and perhaps two inches on the right side:




And




[FONT=&quot]I am thinking that welding on some of the JKS mounts is probably my best bet, but I would appreciate any insights on this. [/FONT]

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

You need to lose the rear sway-bar and prepare for some new springs!

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Ah yes. Springs.

That was another item I meant to bring up.

With the new shackles the various curves of my springs are now quite evident. The classic "U" shape is evolving into a more complex shape, more along the lines of a "W".




But I don't really want a bunch more lift.

I know. Heresy.

But this is a DD.

My current measurement from hub C/L to bottom of fender flare is 19 3/4". That is pretty close to my 3" target. (My understanding is that the factory height was 17", and yes, I still have the original, uncut flares).

From what I have been able to find out about springs a new set will give me a lift now, but then will settle. And I have not found that anyone is raving about the great quality of factory replacement springs.

And of course, if I change the rear springs the front is going to be too low, so I will need to do something up there too.

And the situation with the shock absorbers will get even worse.

And the driveshaft angles will change yet again.

This sounds like deja vu all over again.

But yes, I am interested in suggestions for a stock height rear leaf spring that will not adopt all these interesting curves.

:wow:

And we will see what else I may have forgotten. I only took about 250 pictures. :looney:

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Your springs are completely wasted.



After all that work.............

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

It also appears that your pinion angle is wrong......probably on account of your springs.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

They were completely wasted before that work too.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Agreed, pinion is too high.

Also, Valley Brake in Ontario still arcs shoes.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

What problems will I have with the pinion being too high?

Will springs correct the pinion?

And what is a good quality spring that will not put me over 3.5" total lift?

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Anak said:

What problems will I have with the pinion being too high?

Will springs correct the pinion?

And what is a good quality spring that will not put me over 3.5" total lift?

Click to expand...

Pinion relative to the tail shaft at the trans.....should be parallel. Vibes and ujoint failure.

Stock Dorman springs, $108 to your door. Looks like you can get that 3.5 at the shackle. Or, check out OME rear springs, Or, contact General Spring.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

Your very likely to have draft issues since you have a late model TC! Should probably be prepared for a SYE kit!

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

I would buy junkyard springs before I bought anything from dorman. And if you're going to do springs, I'd wait to address the pinion angle until that. On that connector, the red part should pry out and then you can use a needle to release the pins. Works good for me at work. When I swapped my 8.8 in, I used the ruff stuff shock mounts that come with the kit and mounted the bottom of the shock in about the middle of the axle tube. It's worked well so far and now nothing is hanging low.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

I have several sets of good stock springs, we can build you a very good bastard pack for the cost of center pins and alignment clamps.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

https://goo.gl/images/23G8OG

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

My xj came with a brand new set of dorman 929-301 leafs new in the package.
I installed them with the shackle relocators and extended shackles.
They did fine for a little while.
After 1 trail ride, they were ruined.
They have about 150 miles on then and are permanently bent on each end.

Re: Project Scope Creep: Rear Axle Swap turned into Shackles & Relocation Brackets

JohnX said:

I have several sets of good stock springs, we can build you a very good bastard pack for the cost of center pins and alignment clamps.

Click to expand...

I am all ears.

5/16" center pins?

Four 2 1/2" sets of clamps?

It looks like no problems getting the clamps quickly from Amazon, but the only pins I can find with Prime are 3/8". A quick search tells me I need 5/16". How much of a pain is it to open up each leaf to 3/8"?