drscottsmith

Hello all -

does anyone have the measurement for the largest and smallest points (diameter) of the cylinder inside the clutch master? This is for a 1983 model.

I have a theory I need to test.

thanks in advance.

-Scott

Michael Benno

I dont have the diameter but i have all the other measurements

jcorenman

I don't understand the largest/smallest question, but the ID of the clutch master is 19.05 mm (i.e. 0.750 in). That was measured with telescoping gauges and a micrometer.

drscottsmith

So my clutch master has apparently been leaking for a LONG time - the pad under the carpet is literally soaked. Ugh.

started looking at options. Apparently there is no current rebuild kit right now.

so I got to nosing around and found this online that strongly resembles the innards of the MC. It is for a BMW 3-series. Ordered it for $20. Here are some pics side by side. The piston length and diameter are the same as the original piston for the 928 (minus the little appendage on the end). What is different is the length of the cylinder between the seals. Spring is also obviously a different length.

so in a best case scenario I would just use the BMW piston with the Porsche spring. Worst case, I could use the BMW seals to replace on the Porsche piston.

thoughts?

I am hoping to provide an alternative to new MCs - but I need someone much smarter than I to do a little analysis.

thanks all -

Michael Benno

this may be helpful: https://rennlist.com/forums/928-foru...n-the-car.html

jschiller

You can get an FTE master for under $100 from here:
https://www.partsgeek.com/catalog/19..._cylinder.html
I used this master on my 89 with no issues.

drscottsmith

Early success reported. I believe that the issue with my car was a "mis-adjusted" new piston for the MC - probably been leaking fluid since near day 1 and just got bad enough recently to cause the warning light to come on. There is a LOT of fluid to be cleaned up for sure.

So - I was able to lengthen the shaft and then recut it to the appropriate length as specified by Rob and Stan. I can also confirm that the seals in the BMW kit I purchased seem to be working just fine (went ahead and replaced them while the cylinder was apart). So - from the kit linked below, I believe one can use the piston seals (x2 - but note they are slightly different), the e-clip, and the rubber boot for the operating shaft. Not bad for the price.

Hope this does help someone. Vendors, any chance of finding these seals from suppliers and recreating a clutch master reseal kit? Search FTE-RK19771.
Thanks -

Shirah

Thank you for this, JS
I am buying this today

skpyle

Good Job, Scott!