Diagnostic advice on squeaky rear suspension

[Asiah119]

I've noticed that whenever I'm driving down my street (brick paved) that I sound like some old hoopty squeaking with every bump. I'm lazy and didn't push on all 4 corners when the car was stopped, but the sound is coming from the RR and there is a squeak when I pull\push on the car at that wheel. Is it worth the time\money to just do a complete replace of all of the bushings back there, or to locate which is the offender and replace that one?

[Vas]

Could be your Rear shock mounts or other bushings. What is the mileage of the vehicle?

[Asiah119]

92k range.

[Whammy]

I've noticed that whenever I'm driving down my street (brick paved) that I sound like some old hoopty squeaking with every bump. I'm lazy and didn't push on all 4 corners when the car was stopped, but the sound is coming from the RR and there is a squeak when I pull\push on the car at that wheel. Is it worth the time\money to just do a complete replace of all of the bushings back there, or to locate which is the offender and replace that one?

Asiah,

Considering I have gone through this scenario on my scenario. Allow me to impart some advice/wisdom:

No suspension will last forever. At 100k, you should be start to consider replacing the suspension if you plan on keeping the car (which you should ;)). I wanted until 140,000 (I owned the car starting at 117,000; way overdue). My suspension install (minus labor) cost $1400 for springs, shocks, front/rear shock mounts and reinforcement plates. I used Bilstein and H&R for springs and shocks as well as the reinforcement kit Turner provided. BMW for shocks/struts alone wanted $1400.

However prior to that, take the time to look at a few things:
1.) Put the car either on jack stands, or if you have the option, on a car rack and look underneath. Besides the shocks and struts, bushings must be reviewed. Specifically the differential, subframe, and rear trailing arm bushing (RTAB). Look at the bushings to see if there are cracks. One of my differential bushings looked like this:
http://i81.photobucket.com/albums/j226/duraznostj/E46/IMG_20130812_190045_zpsa7d0b6c2.jpg

This is not good and should be addressed with new bushings. I would avoid polyurethane bushings because my belief is I would want the bushing to give/fail verus the subframe

2.) Especially considering you have a coupe, take a good look at your subframe, bushings, and any cracks. Pre-facelift coupes had subframe issues. This was fixed with the facelifted design, however I would always double check considering the age of the car. I would rather be safe rather than sorry. Even though I have a sedan, I will still look for this.

For springs/shocks, look at your options. For the value/cost, aftermarket is the way to go. Research what spring and shocks you want to go with. I went with H&R Sport Springs and Bilstein Sport Shocks. There is varying options on what shock/strut/ride height is perfer-able. I steered clear of coilover because of prior experience on my 325i.

Reinforcement Kit from Turner: http://www.turnermotorsport.com/p-11799-3-series-strutshock-mount-kit-e46-not-m3-not-xi.aspx

What you choose, I wish you the best of luck!

[BCS_ZHP]

Asiah,
I'm going to take a guess and suspect the squeaking at the right rear corner is the rubber spring pads, there's one on the top & bottom of each rear spring. These are relatively cheap ($10-ish) from the dealer and that should solve your immediate problem of squeaking.

On a refresh, it depends on what you want to do. There's stock, a cup kit, or the full coilover kit which can range from $1K to $3-4K depending upon what your goal is. I decided on a full stock refresh 2 years ago for our coupe (Boss Fane & some others helped with the install), it cost me a little over a grand because I replaced every component in the strut/shock/Spring assemblies except the springs themselves. The ride height is not adjustable and the car sat "stock" high but the ride was as tight, comfortable, and predictable as a new ZHP. We took that stock suspension set up off the car this past summer after only 10-11K miles and it now sits in my garage. Most days I think I'll keep this stock suspension in case we ever want to revert to stock, other days I think maybe I should sell it to someone who needs it, so for now it just sits there.

Feel free to PM me of you have any questions about a suspension refresh. With so many options it can sometimes seem a bit of an overwhelming decision.
Bruce

Bruce

[Asiah119]

Whammy and BCS thanks for the responses, once it gets dry I'll crank the car up and see what I can see.

When it comes up replacing parts, I, of course, want to make any steps up I can reasonably afford but also balance what is affordable and what needs to go and what might as well go while I'm 'in there'. I've started a habit of doing HPDE 2x a year, and will add in a third whenever I can. Part of me is tempted with a setup like the PSS10s and to upgrade the bushings to something stiffer to give less deflection while im on the track. I'm sure that theres a spring\shock setup that will give me the performance that I want and some of the adjustment but I really dont know enough about suspensions to make an informed decision.

[echo46]

Agree with the above advice. I would conjecture that the shocks, mounts and struts are toast by now. Also, RTABS and differential bushings are long in the tooth. I was going to say go OEM rubber bushings but if you are going to track it, AKG polys make a lot of sense. Let us know what is going on under there.