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Francesco
September 5th, 2017, 08:05
Hello all,
I'm in the process of shortening a Dana 44 for the front of my MJ, and I had a curious question about the brackets. Instead of running drop brackets, would it be possible to LIFT the axle side of the brackets ~ 2 inches, to compensate for the lift, or would that cause issues? I realize there could be oil pan clearance issues, but if there were room, would this mess with geometry at all? Logic is telling me know but I figured I'd double check.
Thanks,
Francesco

Francesco
September 6th, 2017, 18:09
The way I see this, is it's the same thing as a drop bracket, it just doesn't hang super low like they would, no?

RCP Phx
September 6th, 2017, 18:26
I tried to raise mine when I was doing new axles for the 95. I did achieve some but the stock spring pockets severely limited the amount they could be raised.

Francesco
September 6th, 2017, 18:33
Thanks for the reply.
My plan was to leave the spring perches at their stock location, however lift the lower control arm mounts about 2" up, so they would be very planed with the axle housing, and do the same for the uppers. This should, in my mind, be almost like the opposite of drop brackets, and would return the control arm angle to stock, while leaving the geometry the same, and would as a benefit, make your ground clearance better as well. Where is there contact exactly?

RCP Phx
September 6th, 2017, 18:40
Your idea is somewhat valid but hard to accomplish w/o redoing everything. Somewhere I not only have my templates(inside and outside are not the same), plus if I looked really hard, I cut 2 sets (chromoly) when I did mine and they're still around somewhere! Worth about 1" gain. Plus I added skids which take up another 1/4" !

Francesco
September 6th, 2017, 18:41
Well I have all new brackets essentially, and figured what's the harm of welding them 1 inch or two inches up? I have a completely stripped axle right now.

RCP Phx
September 6th, 2017, 18:50
There is a down side though to raising them a lot, you need to consider that it affects the torque transfer on the axle. You should visit some of the 4-link calculator sites to see the all what it's characteristics would be.
The factory body mounts are un-equal in length plus they're not parallel.

TRCM
September 6th, 2017, 19:44
No.................... (also do as RCP Phx said above while I was typing and making diagrams I now can't use...LOL)

While it will accomplish what you want, it will give you some weird steering & handling quirks at best. Be undriveable at worst.

1) There has to be a certain amount of separation vertically between the upper & lower mounts on the axle
2) There has to be a certain amount of vertical separation between the upper & lower mounts @ the frame
3) There has to be a certain ratio of the vertical separation of the axle & frame mounts and it is affected by many other factors
4) There has to be a certain amount of distance front to rear between the axle centerline & the mount centerline for both the upper & lower mounts @ the axle
5) There has to be a certain distance between the axle & frame mounts (think control arm length), and that length is related to the separation of the axle & frame side mounts AS WELL as the location of the axle & frame side mounts with respect to the vehicles center of gravity AND the axle centerline

These are all very interrelated, and can be changed and still work well, but it requires a lot of calculation and almost ALL parameters will have to change, not just the location of the 2 mounts to keep it safe. You can fudge a little here & there as RCP Phx said, but the amount you can safely 'fudge' is in % of total, not in inches.


If you change these, you can end up with an undriveable vehicle, as in acceleration can cause the axle to unload, or the suspension to compress, or braking can cause the same things.


Think of it this way.,...you have a lug wrench and you want to loosen a lug nut....what is easier......a 4 way with equal lengths (8") on both side of the center cross, or an 8" breaker bar so both hands are on the same side, or a 2' long breaker bar, but you can only put your hands right side by side up against the socket on the breaker bar.


Let's look at the axle side mounts you want to move...

Right now, stock, the lowers are below the axle centerline a few inches, and the uppers are above by a good amount. For example, lets say the lowers are 3" below and the uppers are 6" above. This does several things, but the main one is braking and acceleration both keep the axle in it's place since the mounts are on opposite sides of the centerline, which give counteractive forces to each (ie 1 in compression and 1 in tension at the same time).

Now, move the lowers up to the axle centerline like you want, and the uppers up to 9" above. You still have the 9" separation, but the axle centerline is now at the lower mount. This is not good in that a panic stop the force won't be applied between the mounts, but all @ 1 or even worse, all on 1 side of both of them.

Putting the mounts where you say you want to will let the front axle dive under acceleration, and lift under braking, which is almost the exact opposite of what you want.

Moving the mounts will almost double to force on the upper mount & arm, which are the weaker ones to begin with. Any rotational force in the stock config is split between the upper & lower mounts, but moving them like you want to do, any rotational force will be almost ALL on the upper mount.

Or try this......or just think about it..........

You have a triangular piece of wood (which simulates the upper, lower & body mount points as viewed from the side), and you want to push it with your finger so that it moves like a boat hull or rocket....1 point leading the way, and the other two following.

Is it easier to do that by pushing on the middle of 1 side, or by pushing on only 1 point ??

Now think of your finger as the force from the axle on the mount points (or triangle points). If you push on 1 point, the triangle spins and doesn't move forward. If you push on a side, the triangle moves basically in the direction you want instead of spinning. This is kinda what will happen to the axle if you put the mounts where you want to.

I hope you can understand what I am trying to say....basically there is a lot of work to get a 4 link to act right & SAFELY under all conditions, you can't just go moving them around. The drop bracket still maintain all of the relationships I mention at the beginning, but moving the axle side mounts won't.

I was gonna put up some diagrams, but there is no way to do so directly from my computer that I see.



.

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Francesco
September 6th, 2017, 21:35
That is exactly what I needed to hear, thank you.

GroversXJ
September 6th, 2017, 22:49
Well, I did exactly what your suggesting. I put in a waggy D44 and welded on my own truss, coil buckets, and mounts but moves them up about 3 inches for the upper mounts and 2.5 for the lower and it worked great. Steers and handles fine, just have the small dead spot in the steering from the inverted T setup I built. Couldn't move the lower mounts up as much due to center section stiffening ribs in the way.
A 4 bar linkage is a 4 bar linkage even if you mount it higher up on the axle. You'll end up with more load on your pivot points for the control arms and the power applied by the drive shaft will put more torque on the housing mounts (longer lever arm) but it works fine.

Sent from my VS810PP using Tapatalk

Francesco
September 7th, 2017, 10:44
Well shoot, there goes my initial thought, as I didn't think that the housing height made a difference. I guess I'll go play around with the calculator to find out

TRCM
September 7th, 2017, 16:08
Well you asked.....1 person said they did it and it works, but also conceded it has issues (like more force on pivot points etc). That person also added trusses and other components that help to strengthen the axle to handle the additional forces that you won't. that may be why his works.

Anyway..............You may do it & get lucky, or you may do it and get hurt.

It's up to you. You'll always find people who say yes and who say no on here. It's up to you to decide.

I simply tried to give you the facts & reasons why. If you still want to do it, it's on you, and good luck.

You need to be sure on this, as if you build an ill-handling vehicle, it can not only hurt you, but others as well if you lose control.




Just like a d35...95% of those on here say not to put a locker in it, you'll break it....well I did, and haven't broken one yet, and I've been driving one for close to 20 yrs total between my 2 cherokees, and do chirp/spin the tires way more than I should.

Francesco
September 7th, 2017, 16:46
No I see where youre coming from 100%. Safety is always first priority, especially because this is street driven, and that is why I'm checking the calculator and asking questions on the forum before blindly doing things. Don't think that I'm disregarding your advice, because that I'm definitely not doing.

chasdb
September 16th, 2017, 20:13
I used the TNT truss with their raised lower control arm mounts for my HP44 swap. I did raise my upper to maintain separation (about 8") and it will push the front axle forward if using the same lower control arms. It was a bitch to get everything to fit with high steer lock to lock and getting the track bar parallel and the same length as the drag link. Since the axle is pushed foreword you need to move the coil buckets back. Lots of juggling, checking for bind at full droop and at bump. I don't think anything is close to stock dimensions anymore. My coils occasionally touch my Antirock but I do like the end product and it's performance.