Click/clatter noise

Opelotus · Opelotus's Garage

Recently, my car has developed an unknown clicking/clattering noise which seems to be coming from the passenger side rear area. I hear it mostly when going over speed bumps at ~5mph, any slower and I don't hear it, nor do I hear it when hitting bumps during normal driving (may be too much road/wind noise at these speeds). It sounds metallic, I think it is somehow related to suspension travel (speed bumps). Any ideas as to what I should check?

Landseer · 09-22-2010, 04:39 PM

First check the bolts that connect the drop links to the sway bars, front and back.

They need to be tight and not have play from the bolt wearing.

More of a clunk than a clatter for me, but I've experienced it on a couple cars.
On one, the noise sounded like it was coming from the rear.
Instead it was the right front.

There are other possibilities, too, like heat shields and rotor shield loose / broken.

Hard to say for sure.

Anthony10370 · Anthony10370's Garage

my friend has a 944 with a similar noise; it happened to be the wheel bearing. Jack the passenger rear tire up and rock it back and forth/top to bottom with the parking brake off (NOT applied), if you feel any movement other than wheel rotation, or any clunking there is a good chance its the wheel bearing. There also should not be any in/out play on the wheel. If there is movement it could also be what Landseer suggested so double check the cause before taking any action.

Opelotus · Opelotus's Garage

Landseer - I replaced the bolts for the drop links about 5 months ago, but I double checked them today and they do not appear to be loose at all. As for heat shields, I had the right rear brake assembly apart last week for some cleanup, no change in the noise, everything is/was tight. The clatter sounds more like something large/important is loose/broken because the noise is loud and clear. My friend followed me out of the parking lot in his car today and he could clearly hear it too. I am quite sure it is coming from the rear as I don't hear it until the rear wheels hit the speed bump. On a side note, the right rear plastic washer/spacer thing which goes around the shock rod under the boot has broken (looks like failure due to age). Noticed it while I was doing the brakes, it split clean in two pieces, which then somehow became stacked one on the other. Not sure of the function of this piece.

Anthony10370 - checked the wheel bearings today as well, no play whatsoever up/down and side/side, will have to check for play in/out again.
Is there any chance it could be CV shafts? Both rear outer shaft boots split wide open since I last checked them 2 weeks ago, pretty sure they are original units.

Landseer · 09-22-2010, 05:51 PM

Well, when the boots crack you need take action. Either exchange yours for rebuilt, or clean, repack and reboot them yourself.

My CV's failed with a clicking noise that varied with car speed and axle position.

Mrmerlin · 09-23-2010, 05:19 AM

repack the CV joints and replace the boots on both inner and outer while you have them out.
Use the WSM to verify CV rebuild as it has to go together a certain way pay attention to the groove in the CV housing take pictures first.
If you want just flush the CV joints out with brake cleaner then replace the boots and grease dont take the balls out of the joints

MPDano · MPDano's Garage

Like Merlin says except I must add, "lots" of brake cleaner. Also, if he has the earlier CV's, wouldn't he have to take one of the CV sides off anyways?

Also, my newly rebuilt CV's (early), the large clamp already fell off and the boot moved off again. I heard better luck with the OEM Porsche Clamp, rather than the screw to tighten clamp included in the kit.

Landseer · 09-23-2010, 05:50 AM

I'm using zip ties on the boots.

Dwayne has a great pictorial write-up on rebuilding a set from his 84.

Let us know if you want a link.

Opelotus · Opelotus's Garage

Thanks for all the tips, I called CarQuest today, they do not sell rebuilt 928 CV shafts. However they have boot kits for $15 each. My question now is whether or not the inner/outer boots are the same, as CarQuest only lists the inners. I plan on completely disassembling/reassembling both shafts myself.

Landseer · 09-23-2010, 07:56 PM

Get them from one of the 928-specific suppliers.

For 84 MY each kit will do one axle. Two boots, two crimp clamps (I don't have crimpers, so I used zip ties), and sticky-faced gaskets for the inner and outer surfaces of the inner CV. It may also have a new metal cap for the inside of the inner CV (against which the bolt heads are tightened). Four packets of grease (2 for the inside CV, 2 for the outside). I've rebuilt 5 or 6 sets now. Not a big deal, just messy.