200q20v Digest, Vol 123, Issue 1

[Jay Kempf]

One thing I have done in the past for things you can't get or things you 
can't rebuild is to buy the nearest a new or rebuilt alternate and 
disassemble it to get the internal guts and rebuild the existing with 
those parts. These master cylinders are supposedly not rebuildable but I 
was able to get one apart and measure it to try to source new seals. So 
if your 4 port one has exactly the same guts you could just take the 
guts out and rebuild the one you have with it. The front snap ring can 
be cut and removed with a Dremel or die grinder with a thin cut off 
wheel. A standard snap ring can be put in it's place. I have done that 
part successfully.

Also, I have been resealing unsleeved aluminum brake and clutch cylinder 
housings for years, probably decades, on high end euro cars. Inspect the 
bore when you get it apart. If it is clean as most are, then reuse it 
with the new seals.

The Porsche 928 has a somewhat notoriously hard to get out clutch 
master. So many rebuild it from the pedal side with the guts of a new 
clutch master by just removing the pedal pushrod, boot and snap ring. 
Then pulling the guts out and putting the new guts in. Just one example 
(happens to be a cast iron housing) but I have done many other oddballs 
like that. Many where I have taken the seals to the seal supply place 
and just gotten the new lip seals (normally 4 for a two chamber master). 
Some master cylinders have different bore diameters for the two diagonal 
or front/rear circuits so disassembly to know what you have to go get is 
key.

Regards,

jfk


>>
>> According to an ATE cross-reference site, the internal specs are the same
>> in terms of bore.  Externally they appear identical save the two
>> additional ports.
>>
>> I have not fitted it yet in case I need to send it back.
>>
>> The question is has anyone used the unit for the standard 200 and capped
>> the two additional brake line feed holes with a threaded plug and then
>> successfully used that BMC in the TQ20V, or are there internal differences
>> that require the original 2 port version?
>>
>> If I can save $230 by altering the 4 port BMC to a 2 port, then I'll be
>> satisfied to drive around town.  No track time intended.
>>
>> Thanks,
>>
>>      - Steve Janesick
>> _______________________________________________
>>
>