Bilstein clunking noise

[Arde]

Have a clunk on the right side suspension since putting the Bilsteins. The ride is firm, and the clunk happens mostly on potholes rather thn bumps. That is when the suspension extends first rather than compress. Nothing looks loose from the outside when checked and manipulated on the lift.

Any likely culprit? Any simple methods for finding it?

[decoupe]

Possibility is the inner/outer CV joint. Dropping into the pothole wold probably put it into the extreme range of articulation and would show up as clunking (mine did anyway).

The attached is from Malc as to checking the CV

Suggestion
Get the rear end up on ramps, so the load is still on the suspension, but you can get underneath. handbrake on! chock those wheels!
Grab each shaft in turn and apply a twist, see if there is play at either side. by trying to turn the prop shaft aback and forth you should be able to work out which one is worn.

Getting the shafts out is relatively easy, undo the Hex head bolts at either end so you could just take them off for a closer inspection...

While your at it repack both CV's on each shaft with grease and change the boots (rubber covers) at the same time, remember they are pretty old!

HTH
Malc

Or it could be something else entirely in which case good luck.

Doug

[Malc]

Arde,
A "clunk" from the suspension could be as doug has suggested, but the other thing to look for is worn:
trailing arm bushes
worn shock absorber bushes (I doubt this if they are new)
Main rear subframe bushes (either end)

If you have access to a ramp see if you can lever the subframe and or trailing arm bushes around, plus the diff mount.
HTH
Malc

[velocewest]

Do you have stock springs or shorter sport springs? In my car, the short ST springs will leave the perch when the car is jacked up. I've never had a problem with it while driving.

[Arde]

The clunk is around the front right strut. Springs are stock. The clunking started when the Bilsteins were installed so that should exonerate other parts of the suspension as they were fine before.

[Malc]

Arde,
Sorry was assuming the rear suspension. With stiffer fronts then other stuff may be moving under sudden load...

If you have access to a lift like before ....
Get the car is up and take the the load off the front suspension and see if anything is slack etc
Other stuff could be engine mounts, exhaust hangers etc so look for signs of the exhaust banging on the body.

However that said I had a brand new rental car recently which crashed and banged over rough roads.... VW polo
Malc

[Arde]

Thanks Malc. Will try on the lift now that I know nothing is exonerated.

[Bill Riblett]

If it is not tight, the shock body will move in the strut and you will get a clunk.

Unfortunately, this means taking the spring out to check it.

[Honolulu]

well, in coupes as in life, there are lots of things that go bump in the night (or day)

Here's the lsit that comes to my mind:

The radius rods from the front of the subframe have bushings at either end, check 'em.
The sway bar links have bushings, check that they are snug.
The upper strut bearing is secured by thre bolts through the inner fender, make sure these are snug.
The strut insert is secured by a big nut in the center of the strut bearing, make sure this is snugged up.
When in doubt, look at the last thing you messed with. thus, check all fasteners you messed with, whether you undid them or not. This is also whty, when I reassemble, it all goes back together real clean. Makes f*ck-ups easier to see and a little less unpleasant to go after.
The lower control arm has a bushing at it's inner end, Jack up the car, put up the jackstands, and shake that control arm.
Heck it could even be in your steering: inner and outer tie rods, center track rod, idler arm bushing, and set the steering box adjustment stud-and-nut..

See? lots of little things to revisit under there.

Have fun, be safe.

[Ed Giguere]

I also hear a very loud "clunk" from my front end when I hit potholes and this has just started to occur since I changed the worn out springs on my '74 for the Red ones Carl sells. The coupe drives much better and handles like a dream, but it is quite an un-nerving experience when I hit a pothole and hear that "clunk". It is a very harsh sound.

I have checked all my suspension components and can not figure it out as everything seems fine.

?

I guess I will just have to try to avoid those damn potholes!

Cheers,
Ed

[KirkT]

Also, keep in mind:

The term "new bushings" is relative for OEM. Buying new bushings and having them wear quickly may not be that odd. Lemforder hasn't made a new batch of these bushing in over 7 years and their useful life-span in only 10 when on the car.

I'm not suggesting that they are all bad, just that it isn't that far fetched to assume a "new"bushing may be at fault.

[corsachili]

There are a lot of potential culprits as the esteemed members of this board have discussed. One possible answer is that the clunk is not necessarily due to anything being loose, it's just a by-product of the stiffer suspension. I have not driven another Bilstein, uprated spring equipped car to compare, but my CSL did the same thing, and every single piece of suspension equipment in the front was brand new, properly tightened, and adjusted. I always thought that it felt like there was something loose too, but I'll be damned if I could find it. The only thing left to check is the actual insert as it sits in the strut. It's possible that the insert is loose in the strut and that the big collar nut is not as tight as it could be. If you have oil in the strut (as called for), which doesn't compress, you might have a situation in which the insert is not completely tight in the strut itself. Just a thought................

[Arde]

Bill was right. Finally had Harold put it on the lift and take it apart. A spacer/shim at the bottom took care of things and now it rides quietly over any surface at any speed. Thanks to all for the checklist.

[coupe74]

I had a brand new Bilstein fail. Mechanic said it was the first he had ever seen. Caused a clunk.