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Okay gang I just finished doing the entire suspension in the car. It has new poly bushings all the way around, along with new shocks. The only thing I did not change was the rear outer tie rods. I just took the car for a drive hoping the suspension would settle in. It definitely rides better than it did before. However, after I returned I couldn't help but notice that the rear sits much higher than what it did before. I did have to replace my rear leaf spring. I don't know if my old one was just that bad or not. I took measurements so that when I put everything back together the alignment would be as close as possible to what it was. The rear end sitting up this high is going to drive me nuts. Does anybody have a clue as to why it might be sitting this high now? Was my rear leaf spring really that bad? And to fix this am I going to have to just get longer bolts for the rear leaf spring to lower it?
I have replaced the spring on a C3 and they clearly "settle" after a couple months especially with new bushings. If you used the same hardware (bolts) you should get it close.
A dealer one time replaced an 8" bolt with a 6 " bolt and that really messed up the height if the rear of the car, it looked like it had been "Jacked Up". After wearing out a set of Half Shafts due to the extreme angle the former owner of VBB in Florida told me what was wrong with my rear and sold me a 8" and 10" set of bolts that go through the ends of the spring.
There are a "bunch of bushings" on the C4 and that alone is a major project but well worth the effort when you are done. I have done one C3 and one C4 and I am not doing that any more!
You don't mention whether the replacement spring was new or used and whether it's the same part number or not. If it's used and was off the donor car a while it might have taken a set.
A little story, part of which may apply to yours. I have a T-Bird that had to have all the springs replaced due to cracks (don't ask, the wife had been driving it). Springs and alignment was done and after that it was so twitchy it was dangerous to drive and the body was higher than it was before. 3 trips back to the dealer and every time they claimed it was 100% correct and live with it. I took it to a shop that specialized in race cars and as soon as I mentioned the model car and having the springs replaced the tech asked if it was doing this, this and this, which it was. They tweaked the alignment a little and this is where it got interesting. It was fall and the tech said to put a sandbag on each corner of the car as close to the spring as possible for the whole winter. Come spring when I took it out of storage the height was right on and drove like a dream.
Maybe consider adding a couple of sandbags for a while over the rear wheels and see if it levels it out for now. Hopefully it will help set the spring given a little time. If it doesn't then look into lowering bolts but that would not be my first choice.
You don't mention whether the replacement spring was new or used and whether it's the same part number or not. If it's used and was off the donor car a while it might have taken a set.
A little story, part of which may apply to yours. I have a T-Bird that had to have all the springs replaced due to cracks (don't ask, the wife had been driving it). Springs and alignment was done and after that it was so twitchy it was dangerous to drive and the body was higher than it was before. 3 trips back to the dealer and every time they claimed it was 100% correct and live with it. I took it to a shop that specialized in race cars and as soon as I mentioned the model car and having the springs replaced the tech asked if it was doing this, this and this, which it was. They tweaked the alignment a little and this is where it got interesting. It was fall and the tech said to put a sandbag on each corner of the car as close to the spring as possible for the whole winter. Come spring when I took it out of storage the height was right on and drove like a dream.
Maybe consider adding a couple of sandbags for a while over the rear wheels and see if it levels it out for now. Hopefully it will help set the spring given a little time. If it doesn't then look into lowering bolts but that would not be my first choice.
It is a used spring. Same part number as the one that was in the car previously. I figured it is probably the fact that the spring has been out of the donor car for who knows how long. It most likely has decompressed. I figure it will settle after awhile.
If it makes you feel any better, I left my cars front end on jackstands with the passenger side hub off all winter and now the passenger front wheel has positive camber and huge wheel gap from the spring decompressing.
I was not aware that you used a previously "used" Spring on your car. You might check the bolts at the ends to be sure that you put the right length bolts back in that location. With a used spring the car should be sitting lower in the rear. If you installed the wrong length bolts that would clearly make it sit up too high. If it is "too high" the half shafts might start to bind a bit and that is not good, trust me on that one. When my rear was up too high the Corvette road like a "Buck-Board" and the shocks were not doing much as they too were stretched out.
On my C3 it was a "new" spring and it was for a Big Block car and it took a couple months to get settled in. A used spring should be at the optimal point almost immediately. Did you use any lubricant on your new bushings? If not it might take longer to settle down. I installed Poly Urethane bushings back in the early 1990's and those things had no built in lubrication so I spray them down once a year sometimes twice to keep them quiet. I have used liquid graphite and dry lubricants that you can spray on that quiets them down and unless I drive in a driving rainstorm I can get away with annual lubrication of the poly bushings. They claim the newer Poly urethane bushings have lubricants built in to prevent the obnoxious squeaking that Poly urethane bushing were known for.
You might try spraying some lubricant on the bushings and see if that helps it settle sooner. I do all the front A-Arm bushings and the entire rear set of bushings, be liberal with the lubricant as it will help IF it can get into the bushing. If you installed it, squirt it with a good lubricant to ensure it settles down.
I hope that this helps a bit. We all want you to get that Corvette back on the road quietly..with no bushing squeaks.
I left my cars front end on jackstands with the passenger side hub off all winter and now the passenger front wheel has positive camber and huge wheel gap from the spring decompressing.
Ha ha ha...I don't think so. Something else is causing that, and hasn't been identified yet.
OP, try just lowering the rear with the stock bolts. See if that gets you where you want it to be. Otherwise, Spend a few bucks and get longer bolts. No need for sand bags and waiting months and months to get your ride height where you want it.
I was not aware that you used a previously "used" Spring on your car. You might check the bolts at the ends to be sure that you put the right length bolts back in that location. With a used spring the car should be sitting lower in the rear. If you installed the wrong length bolts that would clearly make it sit up too high. If it is "too high" the half shafts might start to bind a bit and that is not good, trust me on that one. When my rear was up too high the Corvette road like a "Buck-Board" and the shocks were not doing much as they too were stretched out.
On my C3 it was a "new" spring and it was for a Big Block car and it took a couple months to get settled in. A used spring should be at the optimal point almost immediately. Did you use any lubricant on your new bushings? If not it might take longer to settle down. I installed Poly Urethane bushings back in the early 1990's and those things had no built in lubrication so I spray them down once a year sometimes twice to keep them quiet. I have used liquid graphite and dry lubricants that you can spray on that quiets them down and unless I drive in a driving rainstorm I can get away with annual lubrication of the poly bushings. They claim the newer Poly urethane bushings have lubricants built in to prevent the obnoxious squeaking that Poly urethane bushing were known for.
You might try spraying some lubricant on the bushings and see if that helps it settle sooner. I do all the front A-Arm bushings and the entire rear set of bushings, be liberal with the lubricant as it will help IF it can get into the bushing. If you installed it, squirt it with a good lubricant to ensure it settles down.
I hope that this helps a bit. We all want you to get that Corvette back on the road quietly..with no bushing squeaks.
Best Regards,
Chris
The bolts are the very same that came out during disassembly. I used the super grease that came with the bushings and I even ordered extra. The bushings have plenty of lube.
Originally Posted by ChumpVette
Check to make sure you didn’t install the sway bar upside down.
The sway bar was never removed from the car. Still waiting on the bushings to arrive for that.
Originally Posted by Tom400CFI
Ha ha ha...I don't think so. Something else is causing that, and hasn't been identified yet.
OP, try just lowering the rear with the stock bolts. See if that gets you where you want it to be. Otherwise, Spend a few bucks and get longer bolts. No need for sand bags and waiting months and months to get your ride height where you want it.
I think that may be my solution. I thought maybe I tightened things too tight but I double checked and everything is to specs. Maybe it's because everything is "new" and it just needs some time. I will give it a bit but I may just go the longer bolt route.
I didn't see this addressed in earlier posts: did you check and make absolutely sure that the spacers and insulators in the center spring clamps are in the same order as they were when you took them out? If you got that wrong such that the spring is sitting lower in the clamps, then it would raise the car.
Originally Posted by AudioObsessions
The bolts are the very same that came out during disassembly.
I think that may be my solution. I thought maybe I tightened things too tight but I double checked and everything is to specs. Maybe it's because everything is "new" and it just needs some time. I will give it a bit but I may just go the longer bolt route.
Just to make sure, the nuts on the outer bolts aren't tightened to a torque spec - instead they should be threaded on "until the slot in the nut aligns with the hole in the bolt, and then install the cotter pin" (quote from FSM). I'm just making sure that you didn't tighten the nuts down against the end of the threaded section, because that would probably set the rear ride height well above stock spec.
I didn't see this addressed in earlier posts: did you check and make absolutely sure that the spacers and insulators in the center spring clamps are in the same order as they were when you took them out? If you got that wrong such that the spring is sitting lower in the clamps, then it would raise the car.
Just to make sure, the nuts on the outer bolts aren't tightened to a torque spec - instead they should be threaded on "until the slot in the nut aligns with the hole in the bolt, and then install the cotter pin" (quote from FSM). I'm just making sure that you didn't tighten the nuts down against the end of the threaded section, because that would probably set the rear ride height well above stock spec.
Yeah, the spacers are in the same order, I took pics of everything before disassembly for reference. As for the outer bolts the nut is only screwed on to where the cotter pin goes in. I talked to a GM Tech today that specializes in Corvette and he stated that most likely because the poly bushings are so new they are much stiffer than the original bushings. He said that it may take a while for things to settle in. He also confirmed my theory that the spring after being out of another car for a while would have decompressed. He suggested getting the lowering bolts and getting a 4 wheel alignment done, and then in a year if I want I can switch back to the original spring bolts and get another 4 wheel alignment done.
I talked to a GM Tech today that specializes in Corvette and he stated that most likely because the poly bushings are so new they are much stiffer than the original bushings. He said that it may take a while for things to settle in. He also confirmed my theory that the spring after being out of another car for a while would have decompressed. He suggested getting the lowering bolts and getting a 4 wheel alignment done, and then in a year if I want I can switch back to the original spring bolts and get another 4 wheel alignment done.
Man, you're getting a lot of BS, unfortunately.
1. The GM Tech doesn't "Get it", how poly bushings work. Rubber bushings are bonded to the inner steel sleeve, and the outer steel ring. The outer ring is pressed into each arm and the inner sleeve is clamped by the suspension bolt. SO, the rubber acts slightly like a torsion spring. If you tightened all the bolts with the suspension in full droop/rebound (wheels hanging) then rubber bushings would contribute to a slightly higher ride height.
BUT, you're using poly which doesn't function that way at all; the bushing is lubricated in and out. Therefore it is free to slide/rotate about the inner steel sleeve and w/in the outer rod end. Doesn't matter if it's new, old or in between, the poly bushing should allow very low effort pivoting of each suspension point.
2. The springs doesn't "Decompress". That don't happen. If it did, we'd see two things: First, all NEW 'Vettes would drive around, looking like 4x4's. You know...until they "settle in for a few months". But we don't see that, do we? The second thing we'd see is that all old 'Vettes would be riding on their suspension stops. We don't see that, either. Additionally everyone who jacks and stores their 'Vettes for the winter, wheels hanging, would have "4x4's" again in the spring...but that doesn't happen. Why? The spring doesn't change in that manner, unless it starts to crack/break...in which case, no amount of time "un sprung" is going to help it "decompress". Why do people spread **** like this?
3. If you get longer bolts, you don't need to swap back to the shorter bolts if the car does somehow, end up "settling over a year". You can simply crank up the nuts on the longer bolts to get the rear ride height where you want it.
FYI, I simply bought some inexpensive threaded rod and made my own "longer bolts" for my 'Vette Kart. Simple, cheap, easy, totally adjustable. I never drilled holes for a cotter pin....I just double nut'ed them.
You can see the "bolts" that I made, here....
Last edited by Tom400CFI; May 10, 2019 at 11:58 AM.
1. The GM Tech doesn't "Get it", how poly bushings work. Rubber bushings are bonded to the inner steel sleeve, and the outer steel ring. The outer ring is pressed into each arm and the inner sleeve is clamped by the suspension bolt. SO, the rubber acts slightly like a torsion spring. If you tightened all the bolts with the suspension in full droop/rebound (wheels hanging) then rubber bushings would contribute to a slightly higher ride height.
BUT, you're using poly which doesn't function that way at all; the bushing is lubricated in and out. Therefore it is free to slide/rotate about the inner steel sleeve and w/in the outer rod end. Doesn't matter if it's new, old or in between, the poly bushing should allow very low effort pivoting of each suspension point.
I assume he meant the leaf spring bushings that go on the bolts at the ends of the springs. If the lower ones of those were squashed/flattened with age, then putting in new poly bushings could raise the rear ride height back to stock. But the ride height in the pics sure look higher than stock, so I doubt that even this would explain the situation. I agree with all the rest of what you wrote, though.
Suspension Question
