I just replace all of the rear suspension components in my 69 cutlass and now im getting a squeaking sound when i push down on the back bumper. It didnt happen right away, but after driving it for a few days, its starting to squeak. It has new shocks, springs, boxed lower control arms, and bushings. Everything is stock replacement parts and installed and torqued to spec. It looks and rides great but the squeaking in kind of getting annoying. How do I go about fixing this?

 

Well first you have to figure out which part is causing the squeak.

 

I think its coming from the bushings, but its kind of hard to tell.

 

You can spray them down with some silicone and see if the noise goes away. Are there insulators between the spring and upper pocket?

 

Yes i did replace the upper spring insolators. One thing i forgot to mention, i used wheel bearing grease on the bushings to help install the control arms on the car. I have been doing a little research and have heard that this may be the cause of my squeaking. Will i have to replace my bushings again or is there a way to fix this?

 

I'm not sure how grease would cause squeaking - seems it would have the opposite effect.

Did you use rubber bushings? If so, did you have the weight of the car on the suspension when you torqued the bolts to spec? As in, was the car sitting on the ground with the suspension loaded? Or was the axle hanging down with the body up on stands? The rubber bushings need to be torqued when they are in their "neutral" position, otherwise they may be in a bind.

 

I used rubber bushings and torqued all the bolts with the weight on the suspension. I have heard that petroleum based grease may cause rubber to swell and therfore cause a squeaking noisy. I really hope i dont have to take everything apart again becase it was a real PIA.

 

If you used a thin wipe of grease on the OUTSIDE of the metal shells of the bushings to install them, that is NOT the source of the squeak. Squeaking comes from parts rubbing. When properly installed and torqued, there is NO relative motion between any parts of the bushings and the frame or control arms. The only motion comes from deflections in the rubber parts of the bushings. Look for improperly torqued fasteners, or the shocks or springs. Also, look for worn U-joints that may be squeaking now that they were disturbed when you rebuilt the suspension.

 

Found the problem. Lower control arms are rubbing against the frame.

 

I wonder if the control arm was distorted when the bushings were pressed in or out.

 

Could be, but both arms are rubbing so i doubt it. Guess i have to take the arms off and do a little grinding.

 

Glad you found it. Did you box the lowers or were they like that before?

 

Step away from the grinder!

They didn't squeak from the factory, so why should you need to grind anything? Figure out what is assembled incorrectly and fix THAT.

 

Left arm on right, uppers or lowers? A combination of mixed match?
Grinding not good.

 

A-body cars use the same arms on both sides - there is no RH/LH distinction. If you can get the uppers and lowers reversed, you are the Incredible Hulk. There's about a 3:1 difference in length, not to mention that the uppers only have bushings in the front end, as they fit over the bushings pressed into the axle housing at the back end of the arms. The lowers have bushings in both ends of the arms.

 

Wasn't sure Joe, never had done any R/R on them. Just a thought
and good to know you can't screw them up unless you're the Z Hulk.