I have a 2007 MCS w/ the sport suspension. I have about 43,000 miles. Half of them driven in NYC. I'm starting to hear a thunk from the rear that I think is related to the suspension. I'm not bouncing over bumps but definitely solid thunking. Any advice? Is it the shock or strut or both? What do I need to buy? What is good step up from the OEM sport suspension?

Thanks in advance!

 

OK, first things first: even if you could self-diagnose the issues, do you have the tools and a place to wrench on the car? If not, take it to a competent independent (no need to subsidize half-competent dealers out of warranty).

If you are ready to DIY, can you describe the clunk?
When does it usually occur? Suspension compressing into a put hole? Rebound? - Right or rear corner?

The usual suspects would be the rear shocks and the sway bar links.
It's not unheard of to have an OEM shock fail (my right front seized at ~40K NYC miles). The roads a crap around here, so suspension takes a beating.

Assuming it is the strut, replacing with a set of Koni's all around (Sport/Yellow = single adjustables, or FSD = street friendly) is a good start.
Google or check Amazon for pricing:
http://www.waymotorworks.com/07-10-c...sion/coilover/


Or, depending on your budget and ambition, you can spend a LOT of money on suspension. However, if you mostly drive around NYC streets, I would stay away from lowering the car or stiffening the suspension any further.

HTH,
a

P.S.: Has anything been done recently to the car (break job, etc)?

 

Thunking is coming from a rear and usual with sudden drops, like potholes. No recent work done. I didn't know the sway bar links are a weak point. Thanks for your help!

 

The only way to know is to get it on jack stands and start checking every piece of your suspension. Don't just start throwing parts at an unknown problem.

 

Agreed. I'm having the suspension checked by a professional.

I however have been eyeing new shocks for a while. Any advise on what is good 'cup' shocks which can be used for the track. I don't want anything too harsh or too much drop.

 

From what you are saying here:
I'd check the rules where you are to make sure they're allowed but I would suggest you look at the KONI Sport Yellows as a good starting place. I had a similar case as you with the thunking in the rear at like 40k so I replaced the stock struts and shocks with the KONI FSDs. I also installed a set of Ireland Eng. fixed camber plates. The best move I ever made! Car is completely different in a very good way. The ride is much better and the handling is greatly improved. You can't use the FSD System with lowered springs but you can with the Yellows. The yellows are also adjustable where the FSD's are not. That's my 2cents!