Nicole

Rob: I think it was wise to get the Brembo kits. They include new pistons, and you know they are made for the Porsche/Brembo calipers.

Are you also planning to refinish the exterior of the calipers? If so, you need some stencils to repaint the PORSCHE logo on them. The stencils that are widely available are too large for the rear calipers. I'm planning to have smaller ones made - PM, if you need any!

Larry928GTS

I'm sure some will be absolutely shocked at just the thought of this, but has anyone tried the rebuilt calipers from Rockauto? They list the rebuilt front calipers for the S4 at $136.79 each, and the rebuilt ones for the GTS at $90.79 each, with a $50 core charge for either type.

Rob Edwards

Nicole-

I bought some 3 x 0.21 inch decals from xenonmods.com last May (someone mentioned them) for the rears (6 of them for $9), I was going to use the G2 Black epoxy paint, then put down the decals and clear over them. We'll see if that works.

Nicole

Measure the lenght of the decals before you rely on them. They might be too long for the area they are meant for. The original Porsche lettering that's there is a different font that is higher and shorter.

See below: rear, front, and front with new decal that doesn't fit rear.

Nicholbry

First, Colin (Lizard931), thanks for giving a write up regarding the procedure. I have read, basically, the same procedure on-line and even viewed a video from YouTube that helped a bit, though it was not for our specific calipers. Thanks for your input.

Greg Brown, thanks for the heads up regarding prices and piston sizes. I looked (casually) online and found the front caliper rebuild kit for $25 (assumed it was per piston), and $34 per for the rear. Until now, I thought this was to rebuild 1 complete caliper instead of per piston. Funny me thinking I was actually going to spend less than $200 for parts. Though a bit more expensive, it might be best to hold out for some new GTS calipers per Nicole & Roger's recommendation.

Mark K., I'm not altogether certain I need a caliper rebuild. I just know that the rest of the car was service-neglected; hence a new engine/torque tube/PSD rebuild/etc.; compliments of Greg Brown this year. First off, the brakes squeal when I apply them. I realize this isn't necessarily caliper related, but worth mentioning. Mostly though, the brakes make a loud growling friction sound that resonates through the car when I'm backing the car out of the driveway or going at parking lot speeds. When the auto transmission engages, the shifting force (i.e. from Reverse-to-Drive) even makes the brakes growl loudly...as if the calipers aren't compressing sufficiently and allowing a small amount of travel of the rotor. Also, when in motion (again at parking lot speeds) I can roll down my window and hear a little friction in the back. Aside from the fronts making the squealing noise, they don't make the same growl that the rears do. I hope this was a little more helpful in understanding where I'm at. Now that I've got a new engine, etc I figured it would only be fitting to refurbish brakes that are surely overdue for some attention.

Dwayne, no I'm not anxious to get started right away on this project as I am working on replacing rear springs, shocks, rotors, brake pads on my Saab at the moment (daily driver). I need that up and going first to keep the miles off my Porsche. So, if you're only going to be about a month or so, I might let you pave the path for me. Without a good tutorial complete with detail instructions, step-by-steps, pics, etc. I easily get lost in the details and likely make a potentially fatal mistake. I'm not very mechanically inclined you see.

Worf928, thanks for the heads up on the "H-shaped" pad guides. Although I'm mechanically challenged, I try my best to do things the proper way when I do them (taking no short cuts and asking plenty of questions before hand). Your tip will be helpful when I tear things down.

Rob Edwards, was that $328 for the entire car? If so, that's a deal. I pray the piston sizes are correct for you. Do report back with your findings...

Larry, I thought about RockAuto.com, but I'm just so darned paranoid that someone is going to hastily put things back together and screw things up. Aside from my experience with Greg Brown, I've had the worst luck relying on others to repair things properly. It would bother me to no end wondering if they cleaned the parts up properly, or torqued everything down to spec. If it's within my abilities (and it may not be) I prefer to do as much service on my own as I can. Your recommendation, however, may be worth investigating further. Anyone had experience with their caliper rebuilds from RockAuto?

I thank everyone for chiming in and trying to clear up this subject of caliper rebuilding. I would very much like to be like one of you guys who posts one of those all-too-helpful threads that shows every step to a procedure (timing belt, torque tube replacement, etc). My luck, however, I would go through all the trouble sorting piston sizes, cleaning, re-sealing everything...and have someone say (after it was all complete)...."but you forgot to put _____ back on in the correct position" or something crushing like that. The crazy hospital would probably have to take me away in restraints.

Charley B

This description sounds very similar to the way mine acted when the e-brake was adjusted too tightly.

GregBBRD

[QUOTE=Rob Edwards;6112362]This is a very timely thread, as one of my holiday To-Do's is to rebuild the stock calipers on my '90. I was going to pull all 4 and do them all at once, but perhaps that's not such a good idea? (And why don't the new brakes on all new cars suck, then?)

Regarding parts, after a bunch of reading, trying to understand PET and searching archives, I came up with the following parts list. Each kit contains a new piston, seal, and dust seal:[QUOTE]

You can rebuild all the calipers at the same time....if you use the special Brembo/Porsche lubricant on the pistons and the seals. This will allow the seals and pistons to move in relationship to each other, properly. The caliper repair kits used to come with a small package of this special lubricant. If they no longer do, you can get the proper stuff, from Porsche, using part number 000 043 117 00. The use of the proper lubricant will make the brakes work perfectly, right out of the gate and eliminate the "break-in" that someone mentioned.

If you use brake fluid, or any other lubricant, all bets are off.

Nicholbry

That will be the first thing I inspect then when I tear things down. How does one go about checking/adjusting it? Never mind...I'll search it...I'm sure it's on here somewhere. I've got the WSM on CD too, I'm sure it's there. Thanks for your input.

Nicholbry

Good tip Greg.
The devil's always in the details, isn't it?

GregBBRD

Nicole:

Figured the calipers were on right, but had to ask....I've had many that were not!

Sounds like the pedal is not actually sinking.

Here's the next test. Don't start car. Pump brake pedal a dozen times. The last time, keep steady pressure on the brake pedal (don't let up.) Reach over and start the car.

This will check the booster. If the pedal sinks slightly, when you start the car, that is the booster starting to work.

What year is the car, BTW?

GregBBRD

Any air would be a constant. Pumping the pedal doesn't get rid of the air. Pumping the pedal and releasing doesn't compress the air any more. Therefore, if there is a change in the height of the pedal from pumping, it has to be caused by something other any air that might be in the system.

Nicole

I'm not overly surprised to hear that.

Not beyond a certain point.

Just did the test, and it did exactly what you expected: After pumping 12 times and starting the engine, the pedal became soft and sunk.

1991, VIN 0102

Nicole

As I said, the change from pumping is minimal at best.

GregBBRD

Nicole:

How did the brakes work before the caliper rebuild? Why did they get rebuilt?

mark kibort

sounds like a pad or rear brake issue. there are parts that can break back in the e-brake drum that can cause some nice grinding noise. did you notice to be a periodic noise? (does it have a frequency when you drive or is it just constant?) pads always drag ever so slightly on the rotor, if you had a caliper issue, it probably would be generating some heat in the rotors and the car would be hard to roll by pushing it over a flat surface. Pads and rotors can groove and cause these kinds of noises. Are the rotors grooved? How do the pads look. what kind and how much pad is left?

Pull a caliper and push the pistons in by hand one at a time. Pushing on one, and the other one should go out.

mk