LT1, Please help my ignorance. Telling me it's unsafe, and not giving me the WHY doesn't inform me on the hazards of shimming the front. I read your previous post on the spring pins possible failure, is that the only problem? If so, is there some way to fix it/strenghten it?
My issue is/was a 3" lift, with some Currie greaseable shackles (1/2" longer than stock). That threw/rotated my C's froward, ie caster off, and pinion angle off. To rotate everything back I opted for shims.
So, should I cut off my spring perches, and reweld them back? or something else. Again, just looking for options. I like safety first.
First, Please list your alignment specs,
Then I can better lead you into the right direction.
An alignment is the only correct way to determine correct specifications.
I could tell you it's unsafe to jump off a bridge,
but you would still like the specific reason why it's unsafe.
The reason not to shim the front end is simple.
It's unsafe, It's not the proper way to fix it, It's illegal !!!
Your not only risking your life, But everyone else out driving your roads.
What makes them so bad?
Your Jeep creates a certain amount of rolling momentum. Whenever the brakes are applied, roughly 70 percent of the vehicle's weight is transferred to the front axle. This pitching action causes the front axle to roll forward, thus applying extreme pressure on the front U-bolts and springs. When you add a block shim into the equation it elevates the leverage point on the front axle, causing the axle roll to become even more dramatic. Enough force or pressure can be applied to shoot the front block shim out from between the axle and the spring. This will result in loss of steering, braking and front end control.
Also as mentioned, the pin can shear off, or since the shim has now sucked up length of the pin it is easily possible for the axle to slide off the spring pin due to the lacking depth of the pin.
Well I've been working now on a 1974 Renegade I picked up fro about 2 weeks. It was a struggle to drive with multiple problems. I just discovered the main reason mine wouldn't go straight...........Besides loose U bolts (very loose, nuts came off by HAND!), sloppy springs, a botched add a lift, and worn tie rod ends...the list goes on....... but the killer.......... (cue music)
The rear axle was perched on the pins into the 'other' holes in the perch, instead of the center, on the driver side, pitching the whole axle into pushing the Jeep right all the time....Gotta love POs.!
On the shimming, I am replacing the alum ones for the rear with much thinner machined steel ones. The alumn ones have to be so thick where the steel are thinner and stronger for the back pinion angle, since rewelding axles isn't an option for me right now.
If you are going to use shims at all, use steel ones. It isn't the best to use them front or back really, but if you do, use steel, the alumn ones have to be much thicker for the same angle and still crack/shear, break in half, shear out, kill the pin.
Good machines ones will have a thinner profile to do the same job, have a machined spot to keep the center pin screw shaft straight and take up less in the spring stack. I will agree with all the above posters correcting these things at the axles for pinions /balljoints for caster IS the best way.
Edit: oops, I guess this isn't stickied though the first post says it should be Mea culpa.
I really don't understand why a post is stickied, which implies that it contains the best advice, when the truth is that shimming your front end is not only the wrong way to do things, but is also quite dangerous.
Sure, it's easier to stick a shim on the axle to give you "safer" caster, but overall you are making your vehicle less safe. The right way to do things isn't as easy, but it might save your life, or the lives of your loved ones.
How great would I feel if my cheap-o quick fix was the cause of my kid being hurt? I might never be able to forgive myself.
I apologize if this question repeats any listed above. I bought my '93 cherokee in June. It came with a 3-inch lift on it. My steering was working perfectly until about November, when it started feeling like it slipped a little as I turned the wheel. It's gotten worse since then, but it is a sporadic problem that never seems to act up when someone else goes to look at it. Today when I started driving it, I could turn the wheel about half a turn before anything affected the direction the car was going. All the parts seem to be in working order, and the power steering fluid is normal. Any suggestions about what might be causing this? We hypothesized about the weather (the car used to live on the coast of California, and now lives in Flagstaff with me, where it's around 0 at night) but it seems to do it anywhere. Any help would be much appreciated!
I welded my shims on my front spring perches. They won't be moving around on me. It's basically the same thing as remounting your spring perches to achieve the correct caster angle.
Another thing. If you measure the degree of the slope your vehicle is sitting on before you measure your caster angle, then subtract it or add it (depending if you're facing up hill or down hill) you will come out with the correct angle measurement. As long as you have a solid reference ( and know a little math), you can work around just about anything in the construction world.
I guess I can't tell which are stickied in these forums. The ones I administer, the stickies stay at the top of the forum.
Some folks complained about the number of stickies, so the 'master' sticky was created with links to the formerly stickied threads.
'86 CJ-7 Laredo: 4.2,T-999,D300,D30/D44,'94 YJ tub, full cage, Shrockworks rockers, OYR corners, AC,cruise,restored seats,3 tops,2.5" Superlift,F-T shackle reversal, RS9000x's,35" Dunlop Mud Rovers.
'83 Scrambler: time & money pit under construction with parts from CJ's,YJ's,TJ's,FSJ's,GM,Ford,IH,Honda,Toyota and a whole lotta aftermarket & custom stuff. http://www.jeepskate.net