I was having a problem with brake fluid loss a while back. I changed the master cylinder (for one which had been rebuilt a couple of years back) because it was depositing drips of brake fluid into the footwell. Then I could not get a hard pedal, and the fluid is still going somewhere. Also there is fluid appearing in the pedal box under the master cylinders. Then one morning there is a pool of brake fluid under the drivers side rear wheel. Ok, so I change the rear calliper for one I have lying about. Bleed the brakes, no hard pedal, no real change. Then while trying to fix an earth problem I ended up pulling off the vacuum to the servo. The servo (although apparently working fine) is full of fluid, so off that comes to be replaced by a length of brake pipe. It looks like the clutch master cylinder is porous and dripping fluid into the top of the pedal box. There is no other way it can get there is there? Assuming the pipe union is not leaking, which it seems not to be.
I did not notice at the time but the brake master cylinder that I put on the car has a 5/8 bore. Has anyone here run a plus 2 with that bore and no servo? I do have another one marked "75" but that would give increased pedal pressure would it not? I looked back through the archive and some say that greenstuff pads have a higher friction coefficient than standard pads. I do have a set that I can put on the car if it will make a difference. I have not had a chance to do a test drive because it is not driveable at the moment while I have it apart trying to fix the windows (and other niggles).
As for the clutch master cylinder the one that I think is porous is a 5/8 unit. I have another 5/8 unit, and one that says .70 on it from my yellow plus 2. That always had a really hard switch like clutch. I guess that I will recondition the 5/8 unit. Were .70 cylinders ever used?
And I though that by buying a "rebuilt" car I was going to avoid all of this. Right!
- Third Gear
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- Joined: 10 Mar 2004
- Location: Beckenham Kent
Brake master cylinder 0.7"
clutch master cylinder 0.6252 (5/8th inch)
clutch slave cylinder 0.875 (7/8th inch)
- Coveted Fifth Gear
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It takes a lot for a caliper to leak and I wouldn't expect a m/cyl to become porous. So apart from the leaky servo your problems will be just (hopfully) leaky joints. Check the 3 way by the diff. wipe all the joint dry with paper and be happy that there is no leaks then put some pressure in to the system and recheck.
- Fourth Gear
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The seal kit for +2 (0.70") brake master cyl is Girling SP2431. I may have a spare kit here somewhere if you need one. Rgds jon
- Second Gear
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