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Replaced my broken leaf spring yesterday and installed new bushings,bolts etc. Pretty straightforward. I used the stock size bolts and rear is much higher- too high so I need to adjust. My issue is the stance- From the rear- the car looks bow legged! Can I adjust the camber myself or do I need a shop to do it and until then is it ok to drive the car? If I can adjust myself,can anyone point me to a link to do it? Car is a 92 coupe One more thing- by adjusting the nylon nut( I assume loosening) how much thread is enough showing? Its over 1 inch right now Thanks for any help Paul
It would better at alignment shop. If you just replaced spring and didn't take any of the arms loose it could be ok. Once you set ride height, use an inclinometer to check camber. There is a app. To adjust camber there are cam bolts at bat wing. Toe will change as camber is adjusted. Since you just got car. I would have 4 wheel alignment done. So I know it's right,
First question you say you replaced the Spring and bolts is it a Direct fit Spring (Same as old broken Spring)Did you put the Shim Pack in the way it came out? Is the replacement bolts the same Length, The Question is not the Number of threads but the rough Measurement between the Bushing Mounts (space of Exposed Bolt) if the bolts are the same Length and you still have the old ones just measure the location of the cotter Pin hole (Distance between Head and Hole) and you should you be able to judge from there for a close enough. Your Ride Height may have changed compared to the old to the old probably Nasty played out Bushings you had.
As mentioned before any change to the cams will effect the Toe and the car Should get a 4 wheel alignment
First question you say you replaced the Spring and bolts is it a Direct fit Spring (Same as old broken Spring)Did you put the Shim Pack in the way it came out? Is the replacement bolts the same Length, The Question is not the Number of threads but the rough Measurement between the Bushing Mounts (space of Exposed Bolt) if the bolts are the same Length and you still have the old ones just measure the location of the cotter Pin hole (Distance between Head and Hole) and you should you be able to judge from there for a close enough. Your Ride Height may have changed compared to the old to the old probably Nasty played out Bushings you had.
As mentioned before any change to the cams will effect the Toe and the car Should get a 4 wheel alignment
Set up for 4 wheel alignment next week Tom Tepe Chevrolet $89 quote Matched the cotter pin holes with new same size bolts and nuts are in same position Rear came down nicely Thanks everyone
I'm going to assume you're talking about rear camber here.
Measuring the camber is relatively simple. Camber angle is basically how the wheel tilts either in or out at the top (vs. the bottom). All you need is a level place to park, and a digital level. With the wheels on the car - you want to measure off the "flat" on the wheel just "under" the lip (think of the surface that the tire bead actually seats against). You typically need a couple of equal length spacers, and a nice straight constant thickness board (a piece of aluminum extrustion would be preferred - but is a bit harder to come by). Put the spacers on the wheel at 6 & 12 O'clock, push the wood against them - put the level against the wood, and then measure the angle. (I believe there are angle measurement apps for cell phones - but don't know how accurate they are).
The adjustment is made by loosening the bolt, and turning the "cam" on the lower rods that extend off the lower sides of the diff. Make sure you have the car at the correct ride height when doing this, and make sure the weight is on the tires when taking the measurement.
It's not really that hard to do - and if your alignment is WAY off (after say a bushing replacement) - roughing int he alignment before driving to an alignment shop has some real advantages. But - you need to decide if you really want to do this one yourself.
If the ride height is higher than it used to be and the new bushings you installed are rubber, please make sure that you didn't tighten the control arm bolts (camber rod or trailing arms) until the car was sitting on its tires again. The rubber bushings are captured by the bolts, and the rubber itself moves when the arms move up and down. If you tightened them all while the car was still on jackstands, then they have preload that is raising the ride height.
Either way, you need to get the ride height you want before you take it in for the alignment. If you get it aligned and then lower the ride height, the camber will change again.
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Originally Posted by MatthewMiller
If the ride height is higher than it used to be and the new bushings you installed are rubber, please make sure that you didn't tighten the control arm bolts (camber rod or trailing arms) until the car was sitting on its tires again. The rubber bushings are captured by the bolts, and the rubber itself moves when the arms move up and down. If you tightened them all while the car was still on jackstands, then they have preload that is raising the ride height.
Either way, you need to get the ride height you want before you take it in for the alignment. If you get it aligned and then lower the ride height, the camber will change again.
Of course Matt, his height will be higher than a broken spring. But, your point is something I might have read (yet didn't consider during my own rear bushing rebuild).
From what I remember/saw, the mounting points for arms/rods consists of removable "pins" where the part rotates around them. IOW, none of the removable bolts -- to r/r the t-arm/c-rod assemblies -- rotate when installed. That tells me the arms rotate on/around those rubber/poly "isolated" pins.
I can't see I understand how rubber/poly could be "cinched" into a pre-load....with the POSSIBLE exception of the camber adjustment point. (Of course, during an "on-the-ground" alignment, it would be released).
pnewt, there IS a thread showing how to use string/levels on a level surface to align your car. It's a good thread...with nice instruction. Like you, I opted for a local $89 alignment hoping a laser machine would be better. Plus, the price isn't that bad when you're looking for ANY type of rubber "longevity" on these cars!
(Yeah...who worries about that right-foot rubber-saver! )
Anyway, the shop doing MY alignment insisted those bushings experienced compression loads vs rotational articulation. Personally, I thought their "expert" was F.O.S. There HAS to be rotational articulation for the camber to "flex" and for the rear "axles" to move up/down, right? That said, I also understand how shock can be absorbed through the bushings REDUCING the amount of rotational articulation "required" to handle bumps in the road.
I still don't see how any "preload" would be possible (that would affect ride height). How that's possible would be of interest to me.
pnewt: I just remembered you asked about my sidepipe clearance. I just measured it. It's parked on a fairly level surface but not perfect. My DS measure 3 1/2" while the PS is only 3" off the ground. (This is from the VERY bottom of the fiberglass cover "outlets".) OTOH, I remember measuring 27 1/2" to the apex of the fender well on the alignment machine (presumably level in that scenario).
I am not able to measure the clearance (especially DS) while in the SEAT. We HAVE to assume it drops and likely drops more in the DS. Could the PS rise and the DS dips? Seems possible/likely.
My conclusion is you should shoot for 3 1/4" minimum clearance in your cover outlets. At one point, I remember you saying you'd ordered longer bolts for the springs. I don't know if my measurements would help you decide if those were useable? If this is your first C4 with fiberglass sidepipes/covers, I'm gonna say you're better off NOT flirting with lowest-possible ground clearance (e.g., lowering).
Before I raise my DS rear spring, I cracked that outlet several times. Luckily, I got a gas-station to reimburse me (for my work) when needing to repair the DS cover when contacting one of those fill covers in their station. Also "luckily", I know enough about fiberglass repair that I've done the repairs myself (about 4 times in 10 years). I've always been able to repair/spray the bottom without the rattle-can paint showing.
The covers COULD be reinforced/thickened below the outlets but I've avoided that. I feel it best to let the "non-visible" portion of the outlet flex (or break) when necessary. Better it break UNDER the cover versus where you could potentially SEE a repair.
Of course Matt, his height will be higher than a broken spring.
Well, he said it sits too high now, which I took to mean higher than its original, correct rear ride height.
From what I remember/saw, the mounting points for arms/rods consists of removable "pins" where the part rotates around them. IOW, none of the removable bolts -- to r/r the t-arm/c-rod assemblies -- rotate when installed. That tells me the arms rotate on/around those rubber/poly "isolated" pins.
I can't see I understand how rubber/poly could be "cinched" into a pre-load....with the POSSIBLE exception of the camber adjustment point. (Of course, during an "on-the-ground" alignment, it would be released).
...Anyway, the shop doing MY alignment insisted those bushings experienced compression loads vs rotational articulation. Personally, I thought their "expert" was F.O.S. There HAS to be rotational articulation for the camber to "flex" and for the rear "axles" to move up/down, right? ...I still don't see how any "preload" would be possible (that would affect ride height). How that's possible would be of interest to me.
Okay, let's look at bushing anatomy and installation. Here is a picture of typical control arm rubber bushings:
We've all seen these, and they have three parts: 1) outer metal sleeve/shell, 2) the rubber bushing piece, and 3) the inner bolt sleeve. The key point that you have to understand is that those three pieces are bonded to each other. The rubber cannot turn inside the outer sleeve/shell, and the inner sleeve cannot turn inside the rubber. When the bushing is pressed into the control arm, the outer sleeve/shell cannot turn inside the control arm boss. And when the arm is bolted to its frame bracket, the bolt/nut clamps the bracket onto the inner sleeve so that the inner sleeve cannot rotate in the bracket.
So there are no points in this bushing setup where any piece turns within another part of it - no surfaces slipping on one another and creating any kind of friction. When the control arm rotates around the bolt that forms its axis, the bushing allows that rotation by having the rubber itself twist torsionally within the two sleeves. Imagine the rubber being wrung like a wet towel. The twisting of the rubber itself is the only articulation in these bushings.
If you understand that, then you will understand that the rubber functions as a partially damped torsion spring, and will always want to return to its least "twisted" position. That position is determined by the arm's position when the bolt was tightened (i.e., where the inner sleeve was "clocked" when it was captured by the bracket tension). At any other positive above or below that, the rubber bushing will be creating wheel rate. That's why we want the car at ride height when we tighten the control arm bolts: we want there to be zero preload at ride height. If the car is on jackstands and the arms are at full droop when you tighten the bushing bolts, then the rubber in the bushings will resist the suspension's movement as the suspension gets compressed back toward static ride height. The resulting preload will cause the ride height to be higher.
Note that this is not an issue with bushings made of poly, delrin, or rod ends. In those first two bushings, the inner sleeve actually does rotate within the poly/delrin; and the rod ends have low-friction sliding of the ball within the housing. The have mechanical articulation, rather than articulation through flexure of a material. They add no wheel rate of their own. So with those bushings/joints, you can tighten the control arm bolt with the control arms at any position and it doesn't matter.
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Originally Posted by MatthewMiller
Well, he said it sits too high now, which I took to mean higher than its original, correct rear ride height.
Okay, let's look at bushing anatomy and installation. Here is a picture of typical control arm rubber bushings:
We've all seen these, and they have three parts: 1) outer metal sleeve/shell, 2) the rubber bushing piece, and 3) the inner bolt sleeve. The key point that you have to understand is that those three pieces are bonded to each other. The rubber cannot turn inside the outer sleeve/shell, and the inner sleeve cannot turn inside the rubber. When the bushing is pressed into the control arm, the outer sleeve/shell cannot turn inside the control arm boss. And when the arm is bolted to its frame bracket, the bolt/nut clamps the bracket onto the inner sleeve so that the inner sleeve cannot rotate in the bracket.
So there are no points in this bushing setup where any piece turns within another part of it - no surfaces slipping on one another and creating any kind of friction. When the control arm rotates around the bolt that forms its axis, the bushing allows that rotation by having the rubber itself twist torsionally within the two sleeves. Imagine the rubber being wrung like a wet towel.
My first point of confusion is the necessity for lube choice...like marine lube or "factory" lube. Why lube ANYTHING AT ALL when installing [poly] bushings -- like I did?
My perception is that the inner sleeve (cylinder) is locked into place via mounting bolts. At least, that's how I saw it when rebuilding the rear control arms. I didn't see anything that would prevent the flange-clamped bushing from rotating around that inner sleeve.
So...I don't know that I follow you.
Plus, E.S. even recommends putting lube on the outer surface of the bushings which implies SOME movement is possible between the rods and the bushings.
If it's NOT lube -- to facilitate rotation in/around the metal sleeve/arms, why not call it "glue"? Why not USE glue?
My first point of confusion is the necessity for lube choice...like marine lube or "factory" lube. Why lube ANYTHING AT ALL when installing [poly] bushings -- like I did?
Again, poly bushings DO slip around the inner sleeve, and do not build up preload. That's why you use lube on the inner sleeve. Delrin is the same except it provides its own lubrication, so you don't add any. Rubber bushings are different: no lube, no slipping, and plenty of preload. I'm ***-uming that the OP still has stock-style rubber bushings in his car. But that could be wrong!
My perception is that the inner sleeve (cylinder) is locked into place via mounting bolts.
Yes, it is, regardless of bushing material.
I didn't see anything that would prevent the flange-clamped bushing from rotating around that inner sleeve.
In poly or Delrin, nothing does prevent it (other than some amount of stiction, which minimal). If you have the control arm detached from the upright with poly bushings, you can (hopefully!) move it through its range of travel very easily. If you lift the end up and let go, it may even fall to full droop under its own weight.
Rubber bushings aren't like that at all. The thing that prevents the rubber from rotating around the inner sleeve is that it's actually bonded to the inner sleeve. Notice that rubber bushings never come disassembled, but rather are always assembled units? That's because they are bonded together. If you have rubber bushings and have the arm/balljoint off the upright, you will find increasing resistance as you try to move the arm either in bump or droop from its preferred resting point. That's because the rubber comprises a torsion spring. Also, you'll notice you never use lube on a rubber bushing? Same reason.
Plus, E.S. even recommends putting lube on the outer surface of the bushings which implies SOME movement is possible between the rods and the bushings.
That is almost certainly just to make assembly into the outer sleeve easier. The poly pieces are not meant to rotate inside the outer sleeves - only around the inner sleeve. And because there is so much more surface area around the outer surface of the poly pieces, they won't rotate in the sleeves, even with lube in there. They should always rotate around the inner sleeves.
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Thanks for the clarification. When "knocking/pressing" out the old rubber, it did seem pretty tight/old...I didn't consider it was "fused" though. I drove out the inner metal sleeves using a socket, then I cut off the rubber "flanges" use a sharp sturdy knife. (And, only tried to cut off ONE finger tip! ) I bought a piece of PVC to "press" out the remaining rubber bushings.
After polishing the arms/rods, I inserted my pre-coated poly into the arms. They actually would rotate quite easily. They were a BIT tighter the next day (after the lube "setup") but I wondered why they rotated IN THE RODS/ARMS.
It's interesting that rubber vs poly swaps from twisting to turning. Considering the weight of the car, I'm guessing harder poly is better....though I don't know what EA measures for hardness.
Like I mentioned recently, I do like the result though.
My fronts were rebuilt about 3 yrs ago. A shop did them FOR me in conjunction with an insurance claim. HOWEVER they installed them w/o lube, realized it when they set it on the ground...and had to do it OVER. At least they performed an r/r and added the lube.
Now, I'm left wondering if my mild FRONT (cold) squeaks are a result of that OR... if it's because the sway bar bushings are still original. Guess I'll do those next summer. Can't leave ANYTHING unturned ya know!
Originally Posted by MatthewMiller
If the ride height is higher than it used to be and the new bushings you installed are rubber, please make sure that you didn't tighten the control arm bolts (camber rod or trailing arms) until the car was sitting on its tires again.
We had this discussion in a thread recently. Can't remember if you contributed there. I don't know of any replacement rubber bushings for camber/trailing arms. Sway bars, yes....Spring cushions too....But not the bushings you are talking about. I noticed at least one website lacked clarity on the material (which MIGHT imply rubber was being purchased) though the link was to Energy Suspension (poly).
In short, it's actually almost impossible to replace BUSHING with rubber. That, of course, excludes purchases of NOS arms that still come with rubber.
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Originally Posted by MatthewMiller
That is almost certainly just to make assembly into the outer sleeve easier. The poly pieces are not meant to rotate inside the outer sleeves - only around the inner sleeve. And because there is so much more surface area around the outer surface of the poly pieces, they won't rotate in the sleeves, even with lube in there. They should always rotate around the inner sleeves.
Even WITHOUT lube, the poly bushings SLID right into the arms/rods. I could even rotate them by hand -- which isn't to say they weren't the correct diameter. (There was no "gap")
I DID clean the crap out of the parts -- including running a polishing buff inside the arm/rod eyelets -- to remove micro-scratching from old bushing removal. I was considering (due to the requirement of inner/outer surface lubrication) that surface rotation could occur ANYWHERE. And, as such, I wanted to be certain of a smooth surface that would NOT cause abrasion -- or premature wear.
When you remove old bushings, things aren't very "pretty" in the eyelets. I tried to make them "like new" again before installing the new bushings. Actually, that may have contributed to rods/arms to rotate on occasion? Heck, I even lubed the flanges of the bushings to help insure no squeaking.
FWIW, the front has squeaked since I bought it in 1999 (with 14k miles. During my first CHEVY service, they said it was the front sway bushings. They sprayed them and made it stop....so I believed them. Of course it didn't last (quiet) forever.
So if the poly bushings can easily rotate by hand inside the outer sleeves, I'd probably consider drilling a small hole and threading a sheet metal screw in to pin the pushing in place. I don't think they're supposed to be that easy to turn in the outer sleeve. Or honestly, maybe some type of mild adhesive (maybe pliable RTV?) would be useful there. They should only rotate around the inner sleeve. Lube on the flanges is fine - it would help keep them from squeaking on the tabs of the brackets that hold them in.
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Originally Posted by MatthewMiller
So if the poly bushings can easily rotate by hand inside the outer sleeves, I'd probably consider drilling a small hole and threading a sheet metal screw in to pin the pushing in place. I don't think they're supposed to be that easy to turn in the outer sleeve. Or honestly, maybe some type of mild adhesive (maybe pliable RTV?) would be useful there. They should only rotate around the inner sleeve. Lube on the flanges is fine - it would help keep them from squeaking on the tabs of the brackets that hold them in.
I did call Energy Suspension with the same question before installation. Their desk jockey said coat all sides and run it. THEIR lube is an interesting "hybrid" of some type of silicone anyway. Once I opened/applied it, I felt better it's potential ability to resist modest rotation while also "lubricating" it. Even more so, it's ability to LAST over time.
In fact, when I asked how it could "last for the life of the bushing", he added that the lube "dries" to a form that's very long-lasting. The call was before opening tubes of their lube. MAN THAT STUFF IS STICKY. If you've ever worked with silicone RTV, you have the idea. It sticks to your hands, the vice, the tools, etc... M-E-S-S-Y!!!
Anyway, I don't like the idea of a screw. EPOXY might have been good -- on the outer surface! Unless you wanted to get it back out some day! (OK, OK, I know you can heat to 200-deg to melt it).
Long story short, they've been in the car for several weeks. No complaints so they're not coming back out until/unless I have a problem.
No squeaks in the rear! And....Like I posted recently, I like the improved isolation vs the 28-yr-old original rubber.
Great info everyone. I really appreciate all of your experience and advice. 4 wheel alignment is Thursday so I should be good. I measured the fender opening and is correct now Just seems much higher based on broken spring previously. The service guy at Tepe is a Corvette guy- used to work for Keen Parts in Cincinnati so I am comfortable with his advice also. I had concerns over lift needed and brought car to him yesterday and no problem Again Thanks to all
Had the 4 wheel alignment done this morning at Tom Tepe Chev in Milan Indiana about 4 miles from the house. the before measurements were LF-0.11 toe and the rears were LR 0.9 camber and right rear 1.0 camber and 0.12 toe Everything is within specs now so I am good to go. Only problem I had was the mechanics falling all over themselves looking at the 725 hp supercharged 383!!!!!!! Very enjoyable Thanks for all input on this thread
11-21-2017, 08:59 AM
camber adjustment
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Also "luckily", I know enough about fiberglass repair that I've done the repairs myself (about 4 times in 10 years). I've always been able to repair/spray the bottom without the rattle-can paint showing. 
