Rear rattle/clunking over bumps

[notny41]

The car is a 1986 944 Turbo with 93k miles on it. Almost completely stock.

I have a very frustrating noise coming from the rear of my car whenever I go over bumps in the road - even the little ones.

It especially drives me nuts when I'm on a road that has cracks going across it every 20 feet. It's about enough to drive me crazy.

I think I know what it is, but wanted to find out if others have had this, and if so - what did it turn out to be?

I'm pretty sure that it has something to do with the rear brakes because the noise goes away when I put my foot on the brake pedal and apply even soft pressure to the brakes. Tonight as I was driving and coming to a stop, I pulsed the brakes with my foot and each time I applied pressure to the pedal, I could hear the clunk. Once I was at a stop and if I pulsed the brakes then, there didn't seem to be any noise.

I haven't pulled a wheel off to check and see if I can figure out what's going on yet. Just wondering if anyone else has experienced this and what the issue turned out to be. My guess is there is a spring either on the brake pads that is missing, or a spring on the parking brake shoes missing possibly.

Thanks

[johnb]

The car is a 1986 944 Turbo with 93k miles on it. Almost completely stock.

I have a very frustrating noise coming from the rear of my car whenever I go over bumps in the road - even the little ones.

It especially drives me nuts when I'm on a road that has cracks going across it every 20 feet. It's about enough to drive me crazy.

I think I know what it is, but wanted to find out if others have had this, and if so - what did it turn out to be?

I'm pretty sure that it has something to do with the rear brakes because the noise goes away when I put my foot on the brake pedal and apply even soft pressure to the brakes. Tonight as I was driving and coming to a stop, I pulsed the brakes with my foot and each time I applied pressure to the pedal, I could hear the clunk. Once I was at a stop and if I pulsed the brakes then, there didn't seem to be any noise.

I haven't pulled a wheel off to check and see if I can figure out what's going on yet. Just wondering if anyone else has experienced this and what the issue turned out to be. My guess is there is a spring either on the brake pads that is missing, or a spring on the parking brake shoes missing possibly.

Thanks

I'd say the obvious thing would be the caliper itself being loose. That would explain why it stops with brake pressure. I think it's unlikely to have anything to do with the pads, because there shouldn't be much space for them to move. If there was, that would mean the pistons were retracted a long way, and you'd have to pump the brakes quite a bit to get a solid pedal.

Maybe a loose wheel bearing, but again I'd expect this to give you a very strong signal in terms of feel before it's bad enough to hear anything. The caliper being a little loose wouldn't have any other side effects I can think of other than the noise. No other side effects short term, I mean

[Tom]

Some pads used to do that. If you go in reserve and brake then forward and brake, back and forth, does it clunk? That happens is the pads are shifting back and forth, and at some point they can get loose enough to clunk over bumps. If that's not it, then I'd check the emergency brakes to make sure nothing is loose or broken.

[notny41]

I guess I haven't heard the sound going from reverse to forward and vice versa. I could see it being calipers themselves being loose.

Thanks johnb and Tom for the suggestions. I'll pull the wheel and see what I can find.

[notny41]

The source of my rattling has been identified. I do have a new set of pads on order. Will they all do this or are some pads better than others?

[Tom]

In the old days, some pads were known for clanking like that, but it's been so long I don't know which brands might be good/bad for rattling these days.

But in the meantime, check to see if you have the damping pads in there, part number 928 352 096 11

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[notny41]

Thanks Tom, I’d be willing to bet those aren’t in there. I’ll have a look in a little bit.

Now I have a different problem. I’ve been wanting to bring the rear of the car up a little and I figured that while the wheel was off, I’d see if I could turn the eccentric bolt to give me just a bit more lift. I scribed a line before doing anything and then I used my electric impact wrench to loosen the nuts on both the pinch bolt and the eccentric. I figured that with the rear lifted, the weight of the suspension would move that spring plate in the direction I wanted it to go. instead, it went the opposite way and I think I have essentially lowered the car in the back on that side now. here’s a picture:

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I have a 36mm wrench but it is so long that there is no way I can get it in from the bottom to turn that eccentric bolt.

initially I had only one side jacked up and then thought that maybe since the sway bar kind of connects the two rear wheels together maybe lifting the other side up would help too, but that didn’t seem to help. would disconnecting the sway bar help me out?

Or maybe I need to disconnect the rear shock on that side? Could that be preventing the wishbone from going down further?

I’m not sure how to get that back to where it was before?

[Tom]

I'd start by getting the wrench on it, which probably means jacking the car higher....

[johnb]

You really can't get that much height adjustment from that anyway, maybe 1/2" or so, and it changes both camber and toe when you adjust it. In case you haven't seen it, this is pretty much the best explanation out there of the rear suspension:

[notny41]

yeah i’ve watched Van’s video quite a few times. I think he said in there that there was a different bolt for camber and toe has a separate tool to adjust.

I realize I’m not going to get much adjustment (1/2” maybe), but I don’t need a ton of adjustment.

I ordered a couple things off amazon (36mm crowfoot and a 36mm shallow socket). hopefully that will get me access to that eccentric bolt head. those will be a few days for shipping.

I pulled the brake pads out and there was no dampers in there anywhere.

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