Thread: Clutch Master Cylinder question

Originally Posted by gromit

I'm trying to get my Series 2 mobile (so I can park it somewhere that SWMBO can't see it) and I'm not sure whether a seal is missing from the clutch master cylinder kit I've got.
There is a deep groove at one end of the piston and there was the remains of a seal in it when it was taken apart. The seal remains were soft and squidgy as though it had been softened by the brake fluid.

The kit I have included all the seals except this one, it also included a large rubber washer I assume is for the master cylinder cap. Have I got the kit for a Series 3 rather than Series 2 or are they the same ?

Attached picture shows the new seals in place and the groove in the piston.


Colin

I have not seen one with the extra groove, and looking at cross section in the manual, the only function the extra seal would have is as a backup to the main seal. The large seal has no place in this cylinder, but remember the kit will be to fit several different cylinders.

Series 2 and 3 are identical except that the ones with vacuum assisted dual circuit brakes are fitted with a clutch master cylinder with integral reservoir. But the guts are identical.

Brake fluid does not make seals soft and squidgy - contamination with oil or grease does. I would be inclined to thoroughly bleed the system and consider doing the slave cylinder as well. Make sure that you use rubber grease in the the boot not ordinary grease.

Hope this helps,

John

Thanks John,

I looked at a .pdf of the Series 3 manual last night and couldn't see a groove in the piston there either.
Maybe someone had lubricated the push-rod end with grease which had transferred to this seal to make it soft ? Anyway it's going back on with an empty groove, slave cylinder is on the bench ready to re-seal....

Thanks again,

Colin

here are the photos of my kit when i did mine about 3 months ago.

more photos here :
.Mac Web Gallery

page 3 has the clutch master cyl rebuild...

must take more photos of the project...

Steve

Steve,

Picture IMGP9070 in your gallery shows the clutch master cylinder piston (with no groove), I think the picture you attached may be the seals for the brake master cylinder ?

Colin