dmjames

1984 NA I bought a few months back had some shuddering when braking that I confirmed to be coming from the left rear brake. (Jack up the rear end, spin the wheels, feel the 'pulsing' resistance as the wheel goes around; no similar resistance from any other wheels) So, about 2 weeks ago, I replaced pads and rotors on the rear axle. Calipers looked good, and I cleaned everything up while I was there.

After replacement, the car doesn't have the shudder when stopping, but has in the past week started up with a bit of a pulsating squeak that seems to be about the same frequency as the shudder used to be. What are the next things I should be looking at? The car tracks fine (though I haven't had it aligned), and there doesn't seem to be any play from worn suspension components that I can tell from the standard 'does the wheel wobble when you pull on it' test either.

It does seem like the car may have suffered a hit to the left rear corner at some point- there's some questionably-repaired bodywork there that I'm less and less happy about the more I investigate, but it all looks to have been superficial damage, at least to my relatively untrained eye. Any likely candidates for casualties of that kind of a crash that I should look at as well?

V2Rocket

its getting colder...
squeaky wheel bearing?
my subaru would squeak its RF bearing on cold mornings for the first 1/4 mile until it warmed up and just thumped instead lol

dmjames

Would a squeaking wheel bearing get louder when braking, though? I guess I might have left that out- the squeak is when braking, and at very low speeds, though I think those might be different squeaks.

I'm starting to suspect that my parking brakes are set too tight. I may have gotten a bit overzealous about actually having a car with a working parking brake for the first time in a decade... Will try loosening them a little and see what happens, as I think that might be the source of the non-pulsing squeak at low speeds.

odonnell

If you drive it on the highway for a couple minutes without really braking and pull over, are the calipers warm to the touch?

gtroth

+1
If the caliper is hanging, disk and caliper will get real hot, and disk will warp a little until it cools.

dmjames

Loosened up the parking brakes a touch, and now the more constant squeak at low speeds is gone, but the intermittent one is still there. Haven't had the chance to check for a dragging caliper, but will try to get to that here in the next couple days. I can't remember if I re-greased the slides when I replaced the rear brakes, so I might pull things back apart just to make sure that's done right, too.

Flammulator

I've been having a similar issue on my 83... I chocked it up to the rotors not having been bedded in properly. The previous owner replaced them within the last year, and there's a calliper shaped dark spot on the rear left caliper, right where the brake grabs if you rotate the wheel by hand, just like you described. I've been debating getting the rotor ground down a bit, but have had other priorities.

Not a terribly helpful post, I know, but I'm curious to hear how your issue gets resolved.

dmjames

No, it's good to know it's not just me!

I'm going to try re-bedding things here on my way home from work (if I can find an empty enough chunk of road to work with), and will also be trying the 'is stuff sticking' check probably tomorrow.

As a sidenote, I've been absolutely astonished at how *fast* these cars stop when you really lay into the brakes. It's enough to damned near give yourself whiplash...

Flammulator

I know exactly what you mean about quick stopping. For the first few weeks after having test driven a 944 for the first time, I became concerned that the brakes on every other car I drove were somehow defective. There's something really comforting about the long play and linear control of the 944's brakes. I have yet to drive anything else (save maybe for a Cayman S, but I didn't have a good excuse to slam on the brakes) that feels as controlled under braking.

dmjames

Tried re-bedding the pads, which didn't seem to do much to help. Also confirmed that I'm getting some kind of scrubbing on that left-rear caliper using the 'see if it's hot' strategy. Everything else was cool except for the left rear rotor, which was pretty warm.

Going to re-grease the pins and check parking brake adjustment tonight. Fingers crossed it actually fixes the problem, because otherwise I'm looking at a lot of questions and a lot of obnoxious pieces to replace in figuring it out...

mikey_audiogeek

How much is your rotor runout (measured with a dial gauge)?

dmjames

Not sure, but the rotors were replaced about a month ago, meaning they only have maybe 500 or so miles at this point. I'd have to take the rotor in someplace to get it tested or come up with a gauge to get that figured out.

Seeming like that might be worth the effort, though.

porscharu

This is worth a read. If that rotor is heating up to the point of transfer temp for the brake pad. Every time you stop with your foot on the brake you will be getting deposits which may be why bedding isn't solving the problem. Wheel bearing?

marc abrams

If you do find the caliper hanging, don't overlook the brake hose.

Personally I disagree with the concept of "bedding in" of the brake pads. I feel that a semi metallic, non-racing type of brake pad should broken in with easy driving.

thomasmryan

or the silly parking brake holder spring thingy popping out and letting a shoe or two run amuck.

zero love for those things