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So the master cylinder is leaking into the booster. Yippee. Called a place in Santa Ana and they might be able to rebuild it for $150-200 but need to see if they have the seals. What's the easiest way to take the time hardened plastic inlet pipes out of the top
of the master? Also how do i cycle the ABS when bleeding the system? On my BMW I just use software in my laptop but the Porsche scan tool doesn't seem to have that functionality.
You can use my abs tester to run the abs pump. I've done so successfully.
Good you found the leak. If the mc can't be rebuilt or find another at reasonable cost I'd go 993.
993 master cylinder - 99335591000
993 brake booster - 99335502310
993 master cylinder support bracket - 99335516303
993 booster gasket - 99335530100
BMW brake lines 10mm to 12mm, bend to fit 2x BMW #34326752405
A rebuild it isn't commercially available that I have found but I cant imagine a company that rebuilds them for a living cant find the parts. O-rings and seals come in standard sizes. There is just not a large market for a company to package the proper seals in a kit and sell them. These master cylinders were only used for a short time unlike a GM 1 1/8" master cylinder that was used for over 30 years in 10's of applications.
Thanks Spyerx for the offer. I have your number still and will get in touch when I get it all sorted out. I did find a complete used 993 assembly- brake booster, master, and brackets for super cheap but wonder if ill be going through this same exercise again a few years with a used part. Is the pedal feel that much better for someone who doesn't plan to drive on the track or upgrade to Big Reds.
Ill give it a think and figure it out this week what Im gonna do.
Can you find the Girling part number on the master cylinder? Or measure the bore size? There seems to be plenty of rebuild kits available, just not from Porsche.
Last edited by JasonAndreas; 10-25-2016 at 11:58 AM.
Reason: missed the obvious
Can you find the Girling part number on the master cylinder? Or measure the bore size? There seems to be plenty of rebuild kits available, just not from Porsche.
We know the bore size is 20.64mm or .8125" or 13/16ths. The larger bore 993 is 23.80mm or .9375" or 15/16ths. These are all standard sizes that should be available.
So my buddy is picking this up for me today. Getting a great deal on it. Looks to be in decent shape and from a 993. Do I just swap out the booster (replacing gasket) and the master? Ive read a few posts on here about pushrod length being incorrect for the 964 and having to grind some things. Did any of you have those issues? Going to try to order the BMW brake lines tomorrow.
At a min you need the booster gasket master and bracket.
You will also need to address fact the hard lines are 12mm. Not 10mm. Hence the BMW part numbers above. Right length. 10 to 12 mm. Bend to fit.
I called Porterfield in Costa Mesa today and they said they can cut off the old 10mm fitting and install/flare the 12mm fitting onto the old lines. I see that the bracket for the 993 master cylinder is much shorter, so I assume the master cylinder sticks out of the brake booster further. If I did replace the fittings on the stock lines with minimal cutting, would they still be long enough to reach the new fitting location? I would mock it up but I dont pick up the booster/ms assembly until tomorrow.
Awesome. Never thought to use porter field for that! Good to know since they're local
Yes, the entire assembly is a bit longer, hence the bracket difference
However, I'm not exactly sure of the location of lines relative to stock
That said the soft feed lines do fit ok... so it can't be much movement.
Regardless if it is if they have the stock it's not hard to make new lines.
The BMW lines just happen to be perfect length and size for the job and I think I paid less than $10'ea for them
So I found where all the brake fluid went....As I took the old booster off I took a nice brake fluid shower. There was so much in there I couldn't believe it .
I did get the booster and master cylinder in. OMG was it a pain to wrestle in there. The 993 bracket for the master fits a little snug as well as the booster overall. Having trouble getting the brake lines out of the bulkhead firings by myself. I'll need to get some help for that tomorrow. I hooked the brake pedal up and it doesn't seem to return to the full height of the clutch pedal. Maybe the clutch pedal is out of adjustment or something is fishy with the booster. It's hooked into the bellcrank assembly properly and the booster drew onto the aluminum mounting tube fine with the nuts. Any hints for getting the brake lines loose? Any ideas about why the pedal doesn't come up high enough? The hook on the rod comes about 3/4" short of the metal hoop. Time to clean up now. Also need to stop using my iPhone as a droplight
Looks like he had the same issue with the pedal. I used the existing 964 aluminum mounting tube instead of the 993 one because it was difficult to take out. Also the rod that attaches the bellcrank to the booster, the 993 part had a 964 part number on it. The rubber dust boot also had a 964 number. Just confirmed in PET that the pushrod off the pedal is the same for both cars. The bellcrank and the aluminum bearing bracket aka aluminum mounting tube have unique 993 and 964 numbers in PET.
Looks like ViperBob had the same issue with the rod not being long enough. Secondly my aluminum bracket didn't need to be ground down or at least I don't think it did. I guess Ill just lengthen the brake linkage.
I had Porterfield fab up the brake lines for me. Just needed to provide the 12mm fittings. I had them add 1.5" in both x and y directions. Pick them up at lunch and will try to get them installed tonight.
10-24-2016, 10:36 PM
