Clutch master cylinder

[rjo64]

Hi Guys. Has any one had to change the clutch master cylinder. I have a problem with the clutch and hope this is the problem after reading a previous thread. I have not lost any fluid so hope it is not the slave. Does any one have a part number and is it a straight swap? Thanks

[XLRONYX]

It's a standard 3/4" bore Girling part that we in the US can buy from racer supply stores such as this one:

https://www.pegasusautoracing.com/productselection...

I replaced mine with a 5/8" bore version when I installed a near-clone of AndyGTT's triple disk clutch.



Jeff

[Blu3R]

Jeff,
How would changing to the larger unit affect a standard setup? Would it make the pedal lighter? Any other side effects?

[XLRONYX]

Blu3R said:

Jeff,
How would changing to the larger unit affect a standard setup? Would it make the pedal lighter? Any other side effects?

I don't think that's a good idea unless you also limit pedal travel. The larger master will move the slave proportionally farther for each cm of pedal travel. The clutch will be "faster", and a little harder to modulate (also will make the pedal heavier, not lighter), but my worry is that you could cause too much travel in the slave, or the pressure plate, or both.

Using a smaller master would make the pedal lighter because the slave would move less per cm of pedal travel, but the clutch might not completely disengage.

Jeff

[Scooby P1]

Not sure about any of that....but have been reliably informed i need to change my slave cylinder at some point - which is not so easy!

[Zoobeef]

Scooby P1 said:

Not sure about any of that....but have been reliably informed i need to change my slave cylinder at some point - which is not so easy!

It is easy.......once the box is on the workbench

[Scooby P1]

Excellent news.
Only takes 5 mins to get the 'box out surely?

[Gadgeroonie]

is there a replacement for the slave ? they seem to fail a bit

[andygtt]

Gadgeroonie said:

is there a replacement for the slave ? they seem to fail a bit

It might fail because it is spring loaded so runs on the clutch all the time... the noble bearing is simply the ford bearing with a steel sleeve pressed on the face... I wonder if this extra distance and weight of the sleeve puts more strain on the bearing causing failures?

I use the same bearing but because of my clutch design I removed the spring and now it only runs on the clutch when the pedal is depressed which will significant increase its life.

[Gadgeroonie]

it is the seal that leaks letting clutch fluid into the gearbox

i suspect the stock one can not cope with the stronger pressure plate a Noble has

[TuxMan]

There is a good chance the slave cylinder in Lawrence's car is 8 years old so I suspect it's failure is due to old age rather than design issues .

Tux

[Scooby P1]

Agree Tux, that's probably right.

But the one in my Subaru must be 10 years old, as are the water pipes, pulley bearings etc etc....and none of them break!!

Not going to make Sunday disappointingly as am playing in a tennis tournament which starts at 10.30. Have fun without me, say hi to the gang.

Cheers

[ken7258]

I'm a little confused. It sounds like XLR says the standard size is 3/4" and he put in a 5/8" one. Blu3r asks how does the larger 5/8" one work. 5/8" is not bigger then the stock 3/4" one. Am I missing something here? I'm going to order one and it seems the 3/4 or .75" one is the correct size. Thank you.

[andygtt]

Buy the same size that is on your car.