Clark W

Ok, I'm at my wits end on trying to get the squeals and chirps out of my rear brakes. Chamfering the pads, turning the rotors, checking the run out, adjusting the parking brake, applying anti squeal snake oil, slamming on the brakes while going downhill in reverse have all accomplished nothing. And yes, I have the vibe pucks installed.

My last resort is the calipers. By chance I just R&R'd the rear cylinders on my '78 Celica and was AMAZED at the crap that had accumulated inside them. I know some of you have gone through the rebuild process, but what did you find and, when completed, did it make a difference? My nightmare scenario is to tear the caliper down and find everything in pristine condition.

thanks for any help. -clark

austin944

I don't understand how rebuilding the caliper is going to fix your problem. If there's a lot of crud in the lines it can lead to leaks or sticking calipers, but I don't see how it could cause squealing brakes. Maybe if the fluid is leaking out and getting on the pads, but then I'd think you'd know that by now.

I would make sure that the caliper is sliding freely in the frame, and I would try replacing the pads.

Mighty Shilling

rebuilding the calipers MIGHT help squeal, but it's doubtful. First, look at your pad compound... if it's at all any sort of performance pad, they'll yell at ya. Second, do what I do, and realize that braking is friction of metal on metalish things... and it's wierd that they normally DON'T squeak...

But, if the squeals are there all the time, yeah. definatley rebuild... And rebuilding them couldn't hurt much at all... and it's very easy to do... do you have a turbo? then it's a little tougher... but still very possible.. just pop out the pistons using compressed air, remove the dust boots and pistons, remove the seal on the inside, clean the bores, put the new seals in, grease it up, put the pistons back in (PERFECTLY VERTICAL as to not damage the walls), and put the dust boots back in... they'll be like new...

Check for rust and stuff while you're in there... that'll kill em.. if there is rust, try getting it off LIGHTLY with steel wool... the finest you can find. don't apply much pressure. then continue with replace the seals and grease it up, etc.

Best o luck to you!

if it's an NA, it'll take you 15 minutes once you get the calipers off the car... REALLY easy to rebuild...

Clark W

I've got an s2 so I'm dealing with four piston calipers. No leaks and I've replaced the pads. Pads and rotors are Porsche parts which I've always used and never had a problem with.

Like I said, I'm running out of options and am convinced, based on 15 years of NO PROBLEMS, that somethings amiss. I can only guess that I might be getting uneven pad pressure from the pistions due to sticking, blockage or crud build-up.

I'm resigned to tearing at least one of the calipers apart, I was just hoping that someone could relate to me an experience where in doing so they actually discovered something that might cause what I'm describing here.

-clark

Clark W

Geoff, Thanks for the info. Sounds like I can tackle this in in an afternoon.

What convinces me somethings not right is that I'm only getting it from the left rear and at very slow speeds - literally the last 20 feet before coming to a complete stop. And it's REALLY loud.

As much as I enjoy bleeding the brakes, I'm hopeful I find something to justify the 2nd fluid change in as many months.

-clark

KuHL 951

I'm not sure if this will help but I did pads on the 951 last Summer and I too had a loud noise from one of the rear wheels at the very end of braking. When I pulled the outer pad the leading edge was worn at least 3/16" more than the trailing edge and the inner edge was more worn than the top. It appeared they weren't binding or anything. When I pushed in the pistons for the new pads, the rear piston was sort of tight and then suddenly went in smoothly. I have a feeling that water might have got past the boot and corroded just one area of the piston. I've rechecked that caliper and pad after 5K miles and the wear pattern is uniform with no squealing yet.

Mighty Shilling

Yeah, Clark, rebuilding em isn't that tough... you could knock it out in an afternoon.

Have you sprayed between the pads and rotors with a pressure washer? sometimes mine get dirty... I flush em like that, and no more squeals (from the back... I've racing pads up front... they squeal a lot... I can deafen dogs from like, 3 miles, and I make children cry when I brake...)

Clark W

Ok, So now you've got me thinking. When I replaced the pads I had to use a C clamp to push the pistons back into the caliper EVEN THOUGH I had the bleeder screw opened to allow fluid to escape. Sounds like my pistons are binding.

Thanks man, it would be sweet to see this little annoyance gone for good.

Mighty Shilling

Yes.. it does sound as such. make sure you get some REALLY fine steel wool before you do the rebuild...