924Board.org

[toolbox1211]

Hello, just wondering if anyone has figured out a rebuild seal kit for the brake master cylinder PT# 477611017 for the 1980 924 turbo or any alternatives that are more affordable or possibly swapping in a 944 one and using a brake switch on the pedal.
just wondering what others have done that has worked. thanks
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1980 924 turbo m471

[chuck21401]

I replaced the brake master cylinder in my car recently. I didn't rebuild it, I bought one from FCP Euro. Not inexpensive but it worked as expected.

https://www.fcpeuro.com/products/porsche-brake-master-cylinder-924-53743003237

One thing to mention, be sure to check booster for brake fluid. That's where the fluid went when the seals in my brake master cylinder went bad.

Old


Old and new


New installed

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1981 Porsche 931 w/S1 engine & euro g31 transaxle. Water-cooled intercooler

[toolbox1211]

I saw new master is available a couple places. but if I can avoid spending that asking price and rebuild it, I would much rather do that.

I don't actually know that my current one is blown, purchased car with a blown rear line. I just assume its blown because the car was last driven in 2001 so why wouldn't it be.

the cheaper option never pans out to be an option with this car.

worst-case ill purchase new but figured I would see if anybody had found an alternative method before I finish my brake lines and start messing with the master
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1980 924 turbo m471

[924RACR]

I found an eBay NOS replacement for mine ('81 931) when it went out a couple years ago. But I haven't been enthralled by the pedal since the replacement. Maybe some day I'll get back to it and try another bench bleed and/or some more bleeding. Bigger fish to fry for now.

But I did also keep the original, as a core for a future rebuild... maybe one of these days when prices on a rebuild kit are good...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Beartooth]

I looked around for a kit when I was working on getting my car going, but ended up buying the same one as Chuck. That was partly because there was some pitting in the bore of the old master cylinder, so rebuilding it may have been a waste of time. I know rebuild kits used to be sold, but they're long out of production as far as I can tell. I suppose if the bore of your current master cylinder is clean, it's worth digging around ebay and calling some parts specialists (Einmalig, maybe?), but you may be stuck buying a new one in the end anyway. I kept my old one too; you just never know. It'd probably take some machine work to bore it and put some kind of sleeve in, but I worry that some day that kind of thing will be the only option.
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1980 931 diamond in the rough