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#1 Clutch master cylinder problem

Posted: Tue May 28, 2019 1:05 pm
by Jagman42
I have just had replaced my clutch master cylinder on my S2 which was leaking from the seal. Rather than try a repair kit i foolishly bought a new one and was assured that it would fit. The pedal now seems much weaker in pushdown than it did before fitting and the take up of the clutch is just a few inches from the floor.It was not like this previously. Also after driving a few miles it is difficult to get into reverse and almost as if the clutch is actually only working to halfway capacity. There is no fluid leak and it was all bled correctly they tell me.
I did NOT take a look at the replacement cylinder but was told that it had" 5/8 inch" stamped onto it. Presumably piston size of the cylinder?

Also am i correct that the right master should be part no C27186?
If so I think that the one fitted is incorrect for my car and the pushrod is not long enough to operate the system?
Any thoughts please

#2 Re: Clutch master cylinder problem

Posted: Tue May 28, 2019 2:07 pm
by johnetype
The behaviour you describe is correct if you've fitted a master cylinder with a 5/8th (.625) bore.

The standard E type clutch master cylinder has a 3/4 inch bore and often has 075 or 75 cast on it.

The design of the master cylinder is very common and widely used across lots of cars and also for hydraulic handbrakes hence a variety of sizes are readily available (at varying qualities) from motorsport outlets and eBay.

As you go smaller in master cylinder bore size the easier the clutch is to operate but the longer the travel is needed to engage/disengage - as you've found.

Before you tear it all apart I'd suggest paying careful attention to the adjustment of the slave cylinder pushrod. You should find that it's possible to adjust the pushrod so that the release bearing isn't pressing on the pressure plate with your foot off the clutch pedal but with enough travel to disengage the clutch with the pedal to the floor so you can engage reverse.

Enjoy the lighter clutch action!

#3 Re: Clutch master cylinder problem

Posted: Tue May 28, 2019 3:56 pm
by mgcjag
Hi.....the part number you quote is correct.. https://www.sngbarratt.com/uk/#!/Englis ... f9826cd4e2

#4 Re: Clutch master cylinder problem

Posted: Tue May 28, 2019 8:04 pm
by cactusman
But extremely important that it is not so adjusted such that the release bearing does release completely if the clutch is not depressed. They are carbon and will rapidly wear away.