Putting in a 3" lift this weekend - JeepForum.com
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post #1 of 32 Old 08-25-2016, 11:11 PM Thread Starter
AlexThePhotoGuy
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Putting in a 3" lift this weekend

I'll keep everyone posted on progress, but I'm debating whether or not to put the front shims that came with the kit in...

My 1985 CJ7 is running with 33" tires and a stock suspension. I don't really off road with it, but wanted a little lift to clear the tires more. I went with a Trailmaster 2.5" lift and longer shackles (Warrior) to give it an 0.5" lift there. The kit from TM came with the front and rear shims (definitely plan to use the rear), but with a slight shackle lift, I'm thinking I might be okay without the shims...

Anyone have a similar setup or experience? My initial thinking is to go without, then see how it drives after install and see if I need to make a change. I just thought I'd throw the question out there.

Either way, I'm looking forward to getting rid of my almost flat leaf springs and the feeling of my bump stops and wheel wells being beaten every time the CJ even looks at a speed bump.

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post #2 of 32 Old 08-25-2016, 11:28 PM
y2k-fxst
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You will want an alignment after to check your caster. The shackle lift will reduce the amount that you already have. You should had between 6* and 8* negative caster for best road manors with 33" tires.

I own a Harley and a JEEP, still some people can't figure out why I'm broke!
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post #3 of 32 Old 08-26-2016, 04:45 AM
Matt1981CJ7
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Quote:
Originally Posted by y2k-fxst
You will want an alignment after to check your caster. The shackle lift will reduce the amount that you already have. You should had between 6* and 8* negative caster for best road manors with 33" tires.
Factory spec is 5-7* POSITIVE caster.

OP, you will most likely need the shims, especially with the longer shackles. Don't half-azz it. As stated, have the alignment checked and make the necessary corrections.

Matt


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post #4 of 32 Old 08-26-2016, 07:56 AM
Ken4444
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Quote:
Originally Posted by AlexThePhotoGuy View Post
...My 1985 CJ7 is running with 33" tires and a stock suspension.
Do you happen to know what differential gear ratio is in the axles?

"I give you a republic, if you can keep it." - Benjamin Franklin
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post #5 of 32 Old 08-26-2016, 12:55 PM
LumpyGrits
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OEM R&P for the late 6cyl '7' was either 2:73 or 3:31.
If those are still installed. Your're gonna hate those 33's.
X2 on put'n the shims in.
What tranny do you have?
Be helpful to all of us, if you would fill in your vehicle info.

LG

Have'n you along, is like loose'n 2 good men
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post #6 of 32 Old 08-27-2016, 12:41 AM
y2k-fxst
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Quote:
Originally Posted by Matt1981CJ7 View Post
Factory spec is 5-7* POSITIVE caster.

OP, you will most likely need the shims, especially with the longer shackles. Don't half-azz it. As stated, have the alignment checked and make the necessary corrections.

Matt
Oops, had that back-asward, should have been positive not negative caster. Knew what I wanted to say but, didn't!

Factory spec is 5-7* with stock tires and wheels. But, most find handling is better with larger tires if you go to 6-8* positive caster.

I own a Harley and a JEEP, still some people can't figure out why I'm broke!
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post #7 of 32 Old 08-27-2016, 08:09 AM Thread Starter
AlexThePhotoGuy
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Sorry for not having my profile more detailed. I just updated it. I have the amc 20 with 2.73 gear ratio... I don't do much off roading other than a very occasional trail ride. So far the 33s have been okay, but it's the first Jeep I've owned so I don't know any different!

I definitely plan to have an alignment done afterward and will report the caster number. From the opinions here it sounds like I'll be better off with the shims and taking them out if I need to after my alignment.

Thanks for all of the quick responses! You guys are awesome. In addition to the lift, I'm finally tackling a re-do of the bed liner (P.O. did a pretty crappy one coat job). Here are a couple of pics of the prep work!
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post #8 of 32 Old 08-27-2016, 09:40 AM
LumpyGrits
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2:73 w/33" tires is a poor choice, it also puts lots of torque load on that T5 tranny.
Then there's the deal of the 2-piece OEM rear axles......
LG
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post #9 of 32 Old 08-27-2016, 06:01 PM
y2k-fxst
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Quote:
Originally Posted by AlexThePhotoGuy View Post
I definitely plan to have an alignment done afterward and will report the caster number. From the opinions here it sounds like I'll be better off with the shims and taking them out if I need to after my alignment.
Don't forget the U-bolts are a one-time use only. The threads will distort after being torqued to the correct value. Once fully torqued they should never be re-used.

I own a Harley and a JEEP, still some people can't figure out why I'm broke!
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post #10 of 32 Old 08-27-2016, 08:35 PM Thread Starter
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Today went slow... I found out that the P.O. had removed one of the shackle hanger bolts in order to fit his bumper on. And the remaining single bolt holding it together on the passenger side was loose... so I guess I dodged a bullet doing this project before that bolt broke on the road. I had to grind off the bumper mount (though it's held on in 8 other places) which took a while. Now I can fit two new grade 8 bolts in the hanger holes. So far, I have everything off from the rear suspension and most of the leaf setup back on both sides. I need to attach the last part of the leaf, the U-bolts (I have new ones) and the new shocks. Then on to the front...

The shims are odd in that they are flat but the springs are obviously rounded leaving me very little of the guiding nub to fit into the hole on the axle. I'm guessing they form together once things are tightened a bit? Luckily I have a friend helping out that can work the jack while I work the axle.

Photos attached of that bumper/hanger setup, plus old and new.

As for the 33" tires... they came with the jeep when I bought it a few years back and haven't given me trouble thus far. I don't do any serious wheeling and probably only put 1,500 miles on the CJ a year. Down the road, yeah- re-gear and one piece axles, but at the moment this is the project I have chosen to tackle with my budget.
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post #11 of 32 Old 08-27-2016, 09:00 PM
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Quote:
Originally Posted by AlexThePhotoGuy View Post

The shims are odd in that they are flat but the springs are obviously rounded leaving me very little of the guiding nub to fit into the hole on the axle. I'm guessing they form together once things are tightened a bit? Luckily I have a friend helping out that can work the jack while I work the axle.
You need to remove the center bolt from the springs, and put it through the shims. Use it to bolt the shims to the springs. I have seen a few shims pop out that were just slipped in place.
You may need longer center bolts, depending on the thickness of the shims. As long as you can get a full nut on, you are good with what you have.
A C clamp or two on the springs before you remove the center bolt makes easy work of them.
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post #12 of 32 Old 08-28-2016, 08:45 AM Thread Starter
AlexThePhotoGuy
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Oh- interesting. I thought it just sandwiched between. Does anyone have a picture of that set up? The shim still goes on the top of the springs, right?
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post #13 of 32 Old 08-28-2016, 10:21 AM
LumpyGrits
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Would like to see a side picture of your shims. They should look like a wedge with their angle. Not flat.
LG

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post #14 of 32 Old 08-28-2016, 10:32 AM Thread Starter
AlexThePhotoGuy
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Here's what I've got on there. I still haven't attached anything other than the leafs to the CJ. These are pics of the rear suspension and the fat part of the shim is toward the front of the jeep.
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post #15 of 32 Old 08-28-2016, 01:59 PM
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I am in the process of reversing a install like this......where to start and stay on point.....


Those are aluminum shims, that do not bolt on........not good, as you see they have taken up almost all of the locator pin for the axle. Steel bolt on shims require you to take the center pin out of those springs and you bolt the steel shims to the spring.......that is once you determine what you need for castor and what you need for pinion angle....

I know you do not want to hear this, but I would not install ANY lift shackles as this rotates the axle and changes both castor and pinion angle.........things you might have to fight already just with the lift springs.

You might lucky and still be close enuf on both........you will soon know if you do not check both with a angle meter as it will wander/drift and shake.........and the front drive shaft will vibrate......

The covers some of what I have been correcting on mine from a lift kit and 1 inch lift shackles.......

You might also get by with the stock length brake lines up front.....maybe.

Then you have drag link steering geometry , bump steer etc etc etc in the front.


Out back is pretty straight forward.........brake line length, and pinion angle.......she will buck and vibrate if the angle is not correct.......lift springs might keep it close euff, but the lift shackles will change that more........


A 1/2 lift shackle might not be as bad as a 1 inch lift shackle.........but me and my jeep were both happy when I went back to the stock shackle length.

I would at the least check the castor angle with the aluminum shims so you can figure out which steel shims to get.....2 degree.....4 degree.....6 degree........8 degree............havine a 1/16th of inch of the spring locator pins in the axle flange is no good at all.

Also take note of the drag link angle from the pitman arm to the joint and watch how that moves with the lift and the shackles..........there is some play/forgivness with the ball joints for angle, but the more angle the more bump steer problems you will get, a long with increased wear on the front end components.

A drop pitman arm will correct most of a 2.5 inch lifts differences.


I wish you the best of luck........now is the time to get it right while you have it apart.

Think of a yard stick facing front to back under the jeep............imagine the fulcrum point in the center of the stick, as you add shims or lift shackles , raising or lowering the front of the stick, causes the back of the stick to raise and lower.....back being your pinion angle..........the pinion angle and castor angle are set/welded into the axle.

A movement in one gives the exact movement in the other........assuming the lift springs keep everything exactly the same...castor and pinion, the lift shackles will reduce your castor angle, thus increasing your pinion angle.......those 2 degree shims will rotate the axle to increase your castor , while at the sime time rotating the pinion angle towards the ground.


You have a approx 2 degree window in the castor for the spec......which may or may not give you good handling at either end of the spec.........I do not know the spec for pinion angle to front transfer case angle, but it has to be pretty much spot on with the same angle on both........I believe the rear is the same, as the pinion angle and the transfer case angle have to be spot on or bad things happen.


Castor angle is pretty straight forward ......pinion angles get more complicated.

There are some good youtube vids with mock drivelines set up and painted so you can see the effects of mismatched pinion to transfer case angles ......


I know the post is long.......but I am knee deep right now in correcting all of these things on my jeep.

I just wanted to give you a idea of what is happening with the different parts of a lift........it is changing geometry of all kinds of stuff, which may or may not be a problem and some of it is not just a simple fix as those nice little shims would have you think it is.....

Jeep...the first vehicle on the moon.....next trip we are bringing the tub!

It is gunna cost more and take longer than you thought...plan ahead!
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