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Correcting Rear End Angle

6K views 33 replies 11 participants last post by  DirtyDog 
#1 ·
Installed a set of pro comp leaf spings on the front and back of my stock Jeep 1988 YJ only to find that my rear end is now sitting at too much of an angle.

I am told I am needing a part that corrects this angle so my drive line straightens out again and so my Jeep doesn't vibrate.

Can someone give me a link to the product I need to correct this problem at Quadratec, Amazon, or some other website?

I am told it is called a shim, but all I am finding is shims for leaf springs and nothing to correct the angle of the rear end.

The Pro Comp Springs I installed are these:
http://www.amazon.com/s/ref=nb_sb_n...omp+51423+Black+Powdercoated+Lift+Leaf+Spring
 
#2 ·
When you say the rear end are you talking about the differential? because yes, the shims under the leafs change the angle of the diff. If you're saying your rear end as in back of Jeep sits higher than front, that's a whole other story
 
#3 ·
Yes, it is the rear differential. Sorry for not being clearer.

The U joint is really at an angle now as a result of the lift which I hadn't counted on.

Also, I can't get my track bar to bolt back into the bracket because all of the angles are out of whack.
 
#4 ·
Yes, it is the rear differential. Sorry for not being clearer.

The U joint is really at an angle now as a result of the lift which I hadn't counted on.

Also, I can't get my track bar to bolt back into the bracket because all of the angles are out of whack.
The shim types you're looking for are like this:
http://www.quadratec.com/products/16311_512X_PG.htm

You'll probably need a few to correct driveline angle depending on your lift and such. They get stacked and bolted through your spring perch pin. Use clamps to hold the leafs together when you unbolt it to put the shims in. There is plenty of threads on here that show the correct way to figure out the correct angle your rear axle should be sitting at for your specific Jeep.
 
#6 ·
I am not sure how much of a lift I got, but I' am certian it isn't over 3.5".

I had a stock YJ with four old worn out leaf springs and all I did was order some Pro Comp replacement leaf springs for the front and back.

These are what I ordered for the rear:

http://www.amazon.com/Explorer-Pro-Comp-51423-Powdercoated/dp/B000CNIO7G

All of this started because I hit a big rock on my passenger side and bent up my leaf spring, and my YJ was pulling to the right badly.

To fix the problem, I ordered replacement leaf springs for the front and ended up getting a lift I hadn't bargained for. The Jeep looked really high up front and low in the rear so I ordered two replacements for the back to even it out.

Don't get me wrong, the Jeep looks nice, but now I am having this pinion angle problem and am having to buy new shocks too.

I still haven't figured out which shocks I need for sure and now my Jeep is out of comission. It has been my daily driver since 2004 and I don't know what to do to get it fixed.

Does anybody have some stock leaf springs I could buy so I could maybe get back to stock and fix this problem?

I use the Jeep for highway driving quite a bit too, and I am not sure what negative impacts this lift is going to have for cross country trips and such on the highway.
 
#7 ·
I am not sure how much of a lift I got, but I' am certian it isn't over 3.5".

I had a stock YJ with four old worn out leaf springs and all I did was order some Pro Comp replacement leaf springs for the front and back.

These are what I ordered for the rear:

http://www.amazon.com/Explorer-Pro-Comp-51423-Powdercoated/dp/B000CNIO7G

All of this started because I hit a big rock on my passenger side and bent up my leaf spring, and my YJ was pulling to the right badly.

To fix the problem, I ordered replacement leaf springs for the front and ended up getting a lift I hadn't bargained for. The Jeep looked really high up front and low in the rear so I ordered two replacements for the back to even it out.

Don't get me wrong, the Jeep looks nice, but now I am having this pinion angle problem and am having to buy new shocks too.

I still haven't figured out which shocks I need for sure and now my Jeep is out of comission. It has been my daily driver since 2004 and I don't know what to do to get it fixed.

Does anybody have some stock leaf springs I could buy so I could maybe get back to stock and fix this problem?

I use the Jeep for highway driving quite a bit too, and I am not sure what negative impacts this lift is going to have for cross country trips and such on the highway.
If you have over a 3" lift the transfer case drop 1" is a must. I also heard that motor mount lift 1" will have the same effect. Those are the cheap ways of fixing driveline issues and the tcase drop is pretty simple to do in my opinion.
 
#8 ·
It would be nice to install a sye in your transfer case and then run a cv type driveshaft. If you don't change to a cv type driveshaft than your pinion angle should be closer to parallel to your transfer case output maybe up a couple of degrees but very little. If you switch to an sye and cv shaft then point you pinion strait at your transfer case yoke. The sure and cv is not the cheapest option but is good for long term otherwise a tease drop is in order but don't change your pinion angle to much or you will eat up your u joints. Try some ubolts on your pinion yoke instead of the u joint straps. For some people that has helped with vibes. Make sure your slip yoke doesn't fall out hehe
 
#10 ·
Okay, I am going to put on order the T-Case drop and get the rear differential angle fixed.

I will need 4 new shocks too. Any recommendations?

Is there anything else I will absolutely need besides these things to get back on the road?

At this point, I just want the Jeep driveable again while saving as much time/money as possible. It is my only vehicle for my job which involves alot of travel both on and off road.

I have ended up doing a lift unintentionally by ordering the wrong replacement leaf springs from the start, but since I have already started down this road, I think it will be more expensive for me to back out now and buy a whole new set of OEM leaf springs. Especially considering that all the new leaf springs are already installed.

Is there any type of relocation bracket I will need for the shocks?

I ended up using my existing U bolts and everything seems okay, but I noticed the lift kits have a whole bunch of stuff I don't currently have.

Thanks for all the help thus far.
 
#12 ·
Those springs weren't very informative of how much of a lift they are, " 1"-6" depending on application" is vary vague. To determine the right shocks you figure out the right height of the Jeep now: http://www.jeepforum.com/forum/f12/how-do-i-find-out-what-size-lift-my-yj-has-1091241/ that is a good thread to figure out unknown lifts for YJ's. Then use something like this to get an idea of what shocks will fit your new ride height: http://www.quadratec.com/advisor/jeep_shocks/choose_height.php?year=1988&vn=Jeep+Wrangler. Skyjacker, OME, Fox, Bilstein, Fabtech are all good brands, sure there are more brands as well though. Make sure you get the right ones though because the front shocks are set up for a post at the top and eye at the bottom and the rear shocks are double eye. You can run double eye in the front, but only with additional hardware. I personally run Fox shocks, but my lift kit came with it. Get rid of the track bars because they were set up for your old ride height and will most likely cause issues if you try to keep them in. The leaf springs will have no issues keeping your axles firmly centered under the rig. Also if you are at 3.5" by chance after you measure, you'll be on the cusp of needing a pitarm drop: http://www.quadratec.com/products/1...oglemerchant&gclid=CJGi06ih2bYCFUWo4AodJiYASg so just keep an eye on steering issues.
 
#13 ·
Alright, I took some pictures of the driveline, but I keep getting an error when trying to post them.

Either way, I went ahead and bought a T Case Drop kit today, and the sales person at the shop said that 99% of the time, this fixes my problem. My cost was about $43. Based on the part number for the leaf springs I purchased, the associate at the off road parts shop told me I have a 4" lift. I was dead wrong thinking I only had a 3.5" lift.

I also put a Drop Pitman Arm on order from Quadratec because they didn't have one in stock at the shop. Anyone know the difference between all of the name brands on these drop pitman arms?

The Rugged ridge one is like $20 more than the one I ordered which is Crown brand, but they both say they work with a 4" lift. The all look like a standard piece of steel to me so I tried to budget a little bit on this. Hope I don't regret it later.

Also, I found Ashland's thread where he says you can use 1997 Ford F-150 Rear Shocks to mount on the front of the YJ with a 4" lift and the 1974 Ford F250 rear shocks to mount on the rear.

I am going go this route and see how this works for me.

Thanks to all for the help and suggestions.
 
#14 ·
If you have a pick and pull in your area you can grab a pitman arm from a Grand Cherokee.
They have the same drop as you need and are alot cheaper than the aftermarket drop pitman arms.
 
#15 ·
Just wanted to let everyone know the transfer case drop worked like a charm and eliminated all my vibration problems. I haven't felt any problems with bump steer yet so I plan on holding off on the drop pitman arm installation.

Thanks all for your help.
 
#16 ·
Well, I guess I spoke too soon about the T-Case Drop working like a charm.

I have been having some vibrations the past few days, especially when decelerating.

When I finally got under the Jeep to check, my U Joint nearest the rear axle is completely shot.

Obviously, the bad U Joint is causing my vibration problem. I guess the change in the drive line angle was too much for my U-Joint to handle.

I have ordered two new U-Joints and some Warrior 6 degree steel shims to put under my leaf springs in the hope this will correct my angle problem.

Has anyone out there done a 4" pro comp lift on a YJ before and been able to correct their vibration problems with just a T-Case drop and some shims, or am I destined to have to spend another $600 for the SYE?
 
#17 ·
Well, I guess I spoke too soon about the T-Case Drop working like a charm.

I have been having some vibrations the past few days, especially when decelerating.

When I finally got under the Jeep to check, my U Joint nearest the rear axle is completely shot.

Obviously, the bad U Joint is causing my vibration problem. I guess the change in the drive line angle was too much for my U-Joint to handle.

I have ordered two new U-Joints and some Warrior 6 degree steel shims to put under my leaf springs in the hope this will correct my angle problem.

Has anyone out there done a 4" pro comp lift on a YJ before and been able to correct their vibration problems with just a T-Case drop and some shims, or am I destined to have to spend another $600 for the SYE?
My YJ had a 4" Superlift when I got it with a tcase drop and leaf spring shims without the SYE installed with no vibe issues. I don't have that lift anymore but it worked just fine without the SYE for me.
 
#20 ·
I had a CJ7 with 4" leaf spring lift, 2" shackle lift, and a 1" body lift. The angle was a real problem for me so I did a 1" tcase drop. Instead of shims I removed the spring perches and re welded new ones with the pinion turned up. I can't remember the degree of angle I used on the pinion but it was supposed to be the max before having problems. I had zero vibration problems. I think the shackle lift created a bump steer death trap problem so I shimmed the front axle. I could not turn the pinion on it because the front axle was from a Scout D44 and the spring sat on the edge of the pumpkin which had been professionally milled and I didnt want to mess it up. I have been told shimming the front is a no-no, but it did help the death steer.
 
#21 ·
I have taken some pictures of my drive line and uploaded them to imageshack.

Would you guys take a look and tell me what you think about my angles?

Again, the U-Joint that went bad is the one closest to the rear axle, not the one near the transfer case. If you look closely, the top snapped off.

These are taken from the passenger side of the Jeep.

http://imageshack.com/my/images

The shims that I ordered are 6 degree shims from Warrior, but I don't want to put them in and mess something else up if all I need is new u joints.
 
#23 ·
Based on those photos the axle could be positioned better through a 2 or 4, depending, but a 6 seems too much. I had a 6 on my 6" lift before my 8.8 swap and a 6 would be too much, in my opinion, for a 4". If the vibes only started a few days ago after working for awhile, I would just fix the broken parts and ride that. If the vibes are still there then worry shimming the axle at that point.
 
#24 ·
I believe that with the rear axle dropped 4 inches lower, you will need an angled shim to bring the pinion up a bit even with a TC drop. I dont know if 6 degrees is correct though, it may be. You did right by ordering steel shims, the aluminum ones crack and break apart, then get spit out. My first lift came with aluminum shims, they did not last. When I put my current lift on (3.5 inch) I made some steel shims, they are still intact after lots of hard use.
 
#25 ·
Thanks for the input thus far.

I would hold off on the shims, but I don't want to risk messing up U joints again.

I imagine I will need longer centering pins as a result of having to install shims. Anyone know what length pins I will need?

I am thinking of getting some 4 degree shims as a middle of the road option between the 2 degree and 6 degree.
 
#26 ·
I started a thread recently in the drivetrain section titled need driveline help. I have a 4" procomp lift and had to remove my shims to get everything right. There are before and after pics. My solution might not apply for your problem because I'm running a Chevy 350. You can also check out the billavista tech pages on pirate 4x4. There is some good info there. Sorry I don't know how to post links from the IPod with the jeepforum app

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#29 ·
The way i understood it if your not running a double cardin the pinion shaft and the transfer case shaft should be at the same angle. The transfer case will be higher than the pinion. As long as the drive shaft angle doesnt excede the limits of the u joint throught its travel it will be ok. Someone please correct me if im wrong.

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#31 ·
Thanks Siva for the link but a lot of it was too technical and advanced for me. I did read it though.

I had the damaged U Joint changed today like you suggested without shimming, and I didn't feel any vibrations driving around town.

I am going to run it by the offroad shop tomorrow and have one of the guys take a look and let me know what they think.
 
#32 ·
Thanks Siva for the link but a lot of it was too technical and advanced for me. I did read it though.

I had the damaged U Joint changed today like you suggested without shimming, and I didn't feel any vibrations driving around town.

I am going to run it by the offroad shop tomorrow and have one of the guys take a look and let me know what they think.
That's s good plan. Double check what the shop with is jere on the forum to be sure though

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