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I have a 1985 with the Z51 option. I have the suspension disassembled and was thinking of changing the shim position to lower the car about 3/4".
The rear seems simple, just move the shims from top to bottom and you're done.
I read that you can just remove the front shims. Does anyone here have experience with that?
Looking at the rubber shim assembly on the front leaf, it doesn't look like it was designed to be messed with or disassembled. It looks like it was put on the leaf as one unit, sliding from the end and then stuck in place.
Also, doesn't the spring need room to flex up and down in the crossmember. Would taking out the top shims affect that?
just take the steel shims out completely, the bushing that is clamped on the spring is tough enough to survive without it.
to get the rest of the lowering achieved in the front you will need to shave the end pads.
its a tricky job, I used a hacksaw blade.
if you look at the photo below (this is my Z51 BMB spring), the round mark is where the pad sits on the suspension arm.
just take the steel shims out completely, the bushing that is clamped on the spring is tough enough to survive without it.
to get the rest of the lowering achieved in the front you will need to shave the end pads.
its a tricky job, I used a hacksaw blade.
if you look at the photo below (this is my Z51 BMB spring), the round mark is where the pad sits on the suspension arm.
What year is yours?
http://www.mamotorworks.com/ has a front spring shim kit, and they state that for 84-87 you also need replacement brackets (Front Spring Outer Retainer Upgrade Kit, 1984-1987, 16 Pcs)to allow the shims to be used.
I guess I don't understand how you can remove the shims from the top without having the assembly become loose in the brackets. The brackets on my car 1985, have just enought space to hold the whole assembly tightly to the crossmember.
Edit:
Ok, I think I understand now, the 88+ have the cast aluminum retainer brackets. You have to shorten the brackets to keep the assembly tight when assembled. The stock 84-87 steel stamped brackets aren't modifiable.
Last edited by BlueTwoToneCorvette; Mar 8, 2016 at 06:19 PM.
http://www.mamotorworks.com/ has a front spring shim kit, and they state that for 84-87 you also need replacement brackets (Front Spring Outer Retainer Upgrade Kit, 1984-1987, 16 Pcs)to allow the shims to be used.
I guess I don't understand how you can remove the shims from the top without having the assembly become loose in the brackets. The brackets on my car 1985, have just enought space to hold the whole assembly tightly to the crossmember.
Edit:
Ok, I think I understand now, the 88+ have the cast aluminum retainer brackets. You have to shorten the brackets to keep the assembly tight when assembled. The stock 84-87 steel stamped brackets aren't modifiable.
mine is '85.
they are just trying to sell you stuff you dont need if yours is early 84 -87
The bolts that hold the spring bracket on go through the chassis, so if you take the 1/2" spacer out, then you just end up with 1/2" more thread going thru the top.
The shim stack is exactly .75". The spring end pad is .5" thick. So you have max 1.25" to work with.
I don't think you have a stock clamp?
Taking out the shims would make the spring loose in the clamp, and as you can see you cant chop the ends to make it tighter like the pics I see of the 88+ aluminum clamp. I think that's why they say you need the 88+ style clamp.
One thing I hadn't considered is that if you replace the stock shims with nothing, then the spring top would be jammed flat against the cross member from clamp to clamp. I would think this would greatly increase the spring rate as well as force the spring ends up, effectively lowering the car even more. Maybe good for racing, but I want a decent street car. The stock shims are actually a two piece pivot and allow the spring center to flex up and down in the cross member tube.
I see poly wedges for sale that look about .25"-.5" tall that would allow the spring to flex more like it was designed to.
how you've got it in the first pic is how it bolts back in,
here is a pic of my spring, the steel shim is sitting on the spring behind it, did you have that type of shim on the rubber/steel part that goes around the spring ?
Im pretty sure they used the shims on the softer springs to maintain ride height, so if your car was an original z51 probably didnt have them.
the cheapest option now is to shave the end rubbers.
otherwise you will have to go down the lowering kit route and gluing new rubbers on the top of the spring.
Ok so here is a different lowering question, since you have already worked with this.
It sounds like I can't lower the front any more without cutting the rubber end pads. I didn't measure overall car level front to back before disassembling the suspension. The rear spring shims were all on top of the spring, putting rear height at max. That's two fat aluminum shims plus 2 of the thinner brown composite shims on each bolt assembly. Maybe that's needed for the thicker, flatter Z51 rear springs?
you can experiment with the rear shims,
but its probably easier and you will get a wider range of adjustment if you just put the longer bolts in the rear.
I installed the longer bolts in the rear, and I switched one of the fat shims back there to the bottom of the spring.
I installed the poly wedges up front, along with the aluminum replacement retaining brackets.
I am hoping this will drop the front an inch, then I can adjust the rear bolts to match. Unfortunately I don't have the engine in the car so there is no way to see what the drop is going to be yet.
***Big tip on aligning the front spring left/right on re-installing is to use the old stamped stamped steel retaining brackets to start the install. The old brackets lock solidly into the bottom rubber blocks, where the new ones don't. More importantly, the old bolts allow both brackets to be installed loosely with the spring so you can adjust it left/right before tightening. The new brackets/bolts will not allow you to do this as the bolts are too short and lock the spring against the crossmember before you have a chance to adjust left/right perfectly when putting the end pads into the lower a-arms. When you have the car on the front suspension, just unbolt the old retainers and replace with the new ones
(trimmed to fit of course).
Last edited by BlueTwoToneCorvette; Apr 18, 2016 at 08:05 PM.
Interesting there's another topic on this. Since the last one I bought 4 bilsteins thinkin replacing the kyb shocks would cure my height issue. I put one on the driver side just to test it out and saw no change in height. I can still fit four fingers in between the tire and hood. Aftermarket lowering wedges, cut brackets and lowering bolts and shaved pads contacting the lower a arm. I'm fresh out of ideas at this point other than switching to a z51 spring setup. I'm baffled. I have 6 inches of ground clearance after all the loading "mods"....
Interesting there's another topic on this. Since the last one I bought 4 bilsteins thinkin replacing the kyb shocks would cure my height issue. I put one on the driver side just to test it out and saw no change in height. I can still fit four fingers in between the tire and hood. Aftermarket lowering wedges, cut brackets and lowering bolts and shaved pads contacting the lower a arm. I'm fresh out of ideas at this point other than switching to a z51 spring setup. I'm baffled. I have 6 inches of ground clearance after all the loading "mods"....
Still on stock rubber bushings? They twist tight and hold the suspension up. You don't need to buy lowering wedges just belt sand the rubber. Also those rubber parts pictured above, covering the spring ends, I leave them off completely.
Still on stock rubber bushings? They twist tight and hold the suspension up. You don't need to buy lowering wedges just belt sand the rubber. Also those rubber parts pictured above, covering the spring ends, I leave them off completely.
She sits on urethane bushing all the way around. The rubber pads at the ends of the spring are all gone except for a thin layer to contact the a arm. The only thing I can think of is the new c4 brackets I have need to be cut down even more and the lowering wedges I epoxied on need to be cut down super thin. I don't need it slammed as I've got a canton oil pan a good 3/4" peeking past the engine cradle.
Car is fairly lighter compared to how it was originally. I wonder if that is adding to it.
Lowering 1985 with shims
