mgg

I am curious if anyone out there has removed a shim or two from the rear spring where it is bolted to the diff. Will doing this negatively affect the angle of the halve shalfs. After using the longer bolts to lower the rear of my car, the right side is still significantly higher than the left and I have used the entire length of the bolt. I would like to lower the car approx another 3/4" on the right side but do not have enough bolt as I am at the end of the bolt right now. The left side which is lower still has at least 1" of bolt left to use. I was wondering if removing a shim or two would help this situation but I do not want to stress the half shafts as a result. The only other solution is longer bolts. I would appreciate your thoughts. ( I know coilover would correct this and I have them on my race car but do not want to go that route)
mgg

Aurora40

Hey Mike,

In thinking about it, I believe the shims would only move the spring down, in much the same way as longer bolts. I can only wonder if GM used the shims to set the ride height since the stock springs have a castlenut and are therefore not really adjustable.

They would affect the 1/2 shaft angle in the same way as any lowering, which is to say they would go from less like this: /^\ to more like this -^-

I don't think it would help with the side-to-side variation though, and would make the currently lower side lower still.

You might try talking to Jim, I know he tried several things when trying to level Scott's car. I don't recall if it was successful or not? You could also try posting in C4 tech, as the rear spring isn't ZR-1 specific, it might be some other folks have tried that.

zr1fred

I'm assuming you are talking about moving the shims top to bottom. The bracket would have to be shaved to remove them. It sounds like your spring or shock is bad, or you have a bind to get that much variance.

QB93Z

I agree with Bob. Trying to adjust side-to-side rear end ride height variation with the rear spring shims doesnot work. We tried it on a 1991 ZR-1 that had about 7/8" left to right variation at the rear end. It didn't correct the difference. I also recommend against trying to correct your side-to-side height difference by using "lowering" bolts.

After many hours working on the 1991 car's ride height problem with several of the WAZOO guys, I suspect that the problem starts from the front suspension. In four different sessions, we adjusted every rear end suspension component and did not correct the difference.

If you are interested in having us take a look at your car, please contact me and I will set up a Westminster Maintenance Day. I would like to look at your car and see if there is any comparison to the 1991 we worked on.

My other suggestion is to take the car to a collision repair shop that can do frame straightening and get them to do a 4 wheel alignment and height adjustment.

Good luck,

Jim

ZR-1DUDE

Sounds like something is hammered in there.

I had to put new springs on my ZR-1 after I got it. They had shaved the spring center mount down to lower the car. It was way too low for me. I put i back to stock ride height.

There certainly are ride height variance between the cars. I will have to dig up some pics from back in the day when we were comparing it. I believe we called USA_Won's ZR-1 the 4x4.... :-)

D.

mgg

Thanks for the comments guys. I lowered the front of the car with the wedges as well as the rear of the car with the bolts. The original configuration ( ride height ) was fairly square. I have done this before with my original car and had no problems. We were very careful when reinstalling the springs and double checked everything. I was really surprised to see the difference on the rear spring bolts. I was also quite suprised at the arch in the springs compared to the 1990 Z51 springs. Very little arch in those. The Zr-1 springs lookeded like a rainbow compared to the much flatter and stiffer Z-51 spring. I appreciate all the help and I will try and figure out what is going on. It is not a bad situation just one that bothers me and makes no sense.
I havehad the car aligned at a friend of mines shop who is very good and has excellent equipment. I guess we will proceed to the next step and see what happens.
Thanks again for all of your input.
mgg

MRDZR1

I've inverted the order of those rubber shim to help lowered mine even with the longer bolts. I'm not the only one doing it and I had no issue with the car since doing it.

LT5corsa

Mike,


Why don't you just call out "WAZOO" and schedule an appointment!!!! Looks like we might get together Mid January.

How is that black 90 of yours????


Hope you and your wife are well.




David

ZR WON

I think my car was a trash truck, Hal's 94 was the 4x4....

Brian A.
90 ZR-1
12.09@118
01 Z06
not quite stock

ZR-1DUDE

It was you, me, and Mason.

It was either you or Mason. I thought yours was the 4x4 and the Mopar thing I beat at Beech Bend was the trash truck.

D.

jaymitchell01

Sounds like your spring needs replacing if you haven't done that yet. They tire over the years, and the drivers side always sags first because of the driver weight I imagine. I just replaced mine for that reason.