JOHN383

The rear suspension in my car has never been rebuilt and it now has
an annoying squeak as I drive over bumps in the road. Its hard to isolate where the noise is coming from even when I bounce the car.
The noise is more pronounced as the the suspension warms up
(from adjacent exhaust pipes), after a short drive. I'm sure this
car has well over 100K miles on the frame.

Any suggestions what I should look for and replace?

Frankie the Fink

You could try jacking the car up, getting the weight off the wheels and then push up on the rear tires one at a time while you (or a friend) listens for the squeak. However, with the miles on the car you could easily have more than one problem area.

I just put new rear leaf springs in my car with all new rubber bushings. Up until then I had annoying squeak back there...mostly when backing up then hitting the brakes (car's weight shifting rearwards). Its gone now. I'm betting worn leaf spring bushings or radius rod bushings.

If you are INCREDIBLY lucky it could be a rear shock bushing so if they are old you can more easily try changing those out first.

There are also bushing on the anti-sway bar on the back you can quickly change but I'd be surprised if they make that much noise...worth a try...

JOHN383

How did you know that you needed new springs? Is it ok to rebuild them vs. buy new?

I did replace the shocks... was thinking of disconnecting the sway bar for squeak check.

Frankie the Fink

Its crazy but the car sat and rode ok....but when I had the car on a friend's lift I noticed the springs had only 3 leaves, were mis-matched, no liners, no "rebound clips" and weren't even close to being original. That was my impetus to change them for real, original C1 springs (nobody reproduces the correct springs BTW). If you have original C1 springs in decent shape you'd be crazy not to have them re-arched (if needed) and rebuilt. If your springs are non-original and worn out all the Corvette vendors sell service replacements - but they don't even look original...(e.g. no "groove" down the center of each spring). If you wind up taking the springs off there are some simple measurements to see if they need re-arched which we can go into later.

You can disconnect the sway bar in 10 minutes and take a test drive...you can even disconnect the radius arms and drive around a bit (carefully) to eliminate those. My money is on the leaf spring bushings -- which is a bit of a job to change them out.

JOHN383

I haven't heard the term "re-arch" in reference to springs. I assumed that these were
heat treated from the factory and that an eventual sag was inevitable and metal fatigue
or cracks would result after so many flex cycles. I recall seeing old Ford Mustangs back in the 60's with sagging rear ends ... a problem common to their leaf spring.

Is there a measurement that I should make on the leaf springs once they are out on the table? My vette appears level by eyesight front to rear and right to left.

Also, I do have four leaf springs per side with the groove down the middle... tried squirting
oil in the grooves to eliminate squeak... didn't work!

Frankie the Fink

Wow -- if you search some of my threads in the past 2-3 weeks you can read all about leaf spring replacement. First of all when you remove the leaf springs leave the 4 leaves assembled with the center bolt still through them. Set the springs on the floor so the springs look like an inverted letter "U". (e.g. with the "eyes" on each end on the ground. Measure vertically from an imaginary horizontal line drawn through the CENTER of the eye holes (NOT from the floor) up to the center bolt head on the longest spring -- this is "free arch". It should be between 5-1/2" to 5-3/4" to be within specifications. If both of these are in spec on both sides you are OK...if not then they can be rearched. Here is a "How To" on the measurement: http://www.eatonsprings.com/measuring.htm


Springs do have a service life -- which is why I was glad the C1 set that I found had been in storage for 35 years ! There are two approaches to rearching...one involves literally "beating" them back into shape with a mallet -- I have an article on how to do that. The other (expensive) is to send them off to Eaton spring co. (the original manufacturer of our C1 springs) and they will rearch, reheat and anneal the springs as original and do everything but paint them....that'll be about $600 for the pair !

If the spring "liners" (the fiber board inserts between the springs) are worn out you could very well get a squeak in that area...

JOHN383

Great info... looks like you've done your homework. I'll use your 5 1/2" - 5 3/4" measurement as a guide and pick up the rebuild kit. Thanks very much!

Frankie the Fink

If you really want the correct stuff then Paragon has the rebuild kit (about $144 for both sides): part number: SU-1070. Their liners are the correct paraffin-soaked fiberboard with the center bolt hole already punched, metal end caps, muslin-wrapped at the ends and with the four little metal "slugs" already installed around the center bolt hole. They also include the correct "bands" and clips for a complete rebuild in this same kit.

JOHN383

Just finished taking both sides apart. Frt hanger brackets were bad (somebody welded the pins to the bracket) ... had to torch the bracket to free the spring. Both pins were undersize from corrosion. I usually get my parts from Corvette America. Do you know if their kit is the same as Paragon? Also, is a special tool required to tighten the bands or will pliers work?

Both sets of springs are the same profile (height) and are around the 5 1/2" center height measurement which you indicated.

Frankie the Fink

That front "box" that houses the front eye on the springs is notorious for having bolts rusted in place and the zany "pin bolts" with the big head can be a PITA. I knocked mine loose with a mallet and then used a tie rod "pickle fork" under the knurled head to drive it the rest of the way out. They DO make those front "boxes" reproduction...Corvette Central has them for $55 EACH. I have two brand new pin bolts (with lock washers and nuts) I'll sell you for a decent price if you need them...the old ones on my car were actually OK so I just reused them.

Can't say on other vendor's (e.g. Corvette America) products but the kit from Paragon was first rate...don't think its worth the gamble to go elsewhere. Look at the quality of the liners in the first picture - near factory perfect.

You really should use a crimping tool on the bands...the original tool produced a single notch crimp...the one I used produces a double notch crimp but works fine (see second picture). If you're not getting your car judged then this tool that I used worked fine: http://www.ebay.com/itm/230495775266?ssPageName=STRK:MEWNX:IT&_t rksid=p3984.m1439.l2649