Rebuilt the Front Brakes - Nasty Grime Inside! (pics)

[exitwound]

I spent the day cleaning and rebuilding the front brakes. I'll tell you, when the boots are ripped and the calipers are covered in dirt, it's guaranteed that the cylinder itself will be just as gross. And I was right.





They're shiny and clean now!

I want to give thanks to Scott Harvey over at Rennlist for writing up a nice rebuild article with plenty of pictures to guide me through this. I've done all four wheels now and he was very helpful.

[Arizona_928]

wow.. how long did it take?

[exitwound]

Took about 3 hours to do both, maybe 4. This includes the bleeding too. I'm sure the next time I do it, it'll take 1/2 that as this was my first time doing it alone. The longest part of the process was trying to reassemble the 3 parts of the caliper. It can be a really tight fit.

[Slam]

Mine weren't quite that bad, but close. Did you have much trouble getting the pistons out? One of mine hung up and was a pin to get out.

Any pics of after the refit?

[John_AZ]

Originally Posted by exitwound

Took about 3 hours to do both, maybe 4. This includes the bleeding too. I'm sure the next time I do it, it'll take 1/2 that as this was my first time doing it alone. The longest part of the process was trying to reassemble the 3 parts of the caliper. It can be a really tight fit.

Mine have cuts also. Do you have a link for the rebuild info? What type of brake fluid did you go with? Thanks.

John_AZ
1988 924S + 1987 924S

[exitwound]

I don't have compressed air at the house here so getting the pistons out that way wasn't an option. The piston on the driver's side came out a little when i pulled it with my fingers, but not all the way. What I had to do was reconnect the caliper and have a buddy slowly press on the pedal a few times until it moved far enough out that I could pull it the rest of the way out. Pulled out rather easily with both the bleeder valve and the hose fitting open. Was a little stuck though due to the dirt.

I went with DOT4 brake fluid just to be safe. I had done the clutch with DOT4 last time too. Not that I expect any temperatures near boiling on the brakes as this is an N/A and a daily (city) driver.

I didn't take any pics after the rebuild, sorry. I plan on reshining and/or painting the calipers next time I'm in there and have a free weekend. The pistons didnt' come 100% clean, but they were smooth. There was still a red/brown film over its surface but slid into the caliper fine. It was good enough for a used caliper. If I ever have them fail, i'll end up replacing with new bores.

I'll try to attach the .doc file that Scott Harvey sent me last year regarding the rebuilds. He wrote it and took the pictures. THey're not 944 calipers in the article, but the principles are the same.

The file is 2.2MB and can be found by clicking here.

[John_AZ]

Great brake write up file!

John_AZ

[trentwat]

I was recently working on the frontend and ended up having to crack open the caliper (one side only) to get it off the strut (bronken mounting bolt). This wasn't in the original plan.

I am being told that this project (at least on the side of the creacked open caliper) will need addt'l work around the four O-rings (?). I have the parts for two rebuilds and the addt'l O-rings for the side with the F-up.

After reading the Rebuild Doc in this thread, I still can't seem to find where the O-rings come in to play. Any ideas? Should I do the O-ring thing on both sides? What have I gotten myself into?