Clutch master cylinder replacement

[xavier]

The wiki has an article on clutch slave cylinder replacement, but I cannot find one on replacing the master cylinder. I have been told its best to do both at once. Is there an article on replacing the master cylinder anywhere?

[pacerpete]

If your master cylinder is not leaking and works ok, leave it alone. When you change the slave , remove the reservoir and clean it out and bleed the slave through until clean fluid comes out and you should be fine.

[capri_rob]

Slave and master cylinders are both horrible fiddly jobs.

Should ideally be done in pairs as when one fails the other wont be far behind

Access on the bolts that hold the master in place is poor - you will be upside down with sweat dripping into your eyes swearing for what seems like eternity.

[G-Bear]

I think I got lucky on this job as my master came off and new one on quite easy. Drain the system of fluid. Disconnect the steel hose first that is attached to the end of the master cylinder poking out in the engine bay. Take out the housing under the steering wheel. Then squeeze yourself into the footwell with socket sets and a torch. From what I can remember there's 17mm bolt to take off that connects the clutch pedal to the master. Then undo the two 13mm (I think) bolts that hold the cylinder itself in place. These two are a touch fiddly. I think I used an extension bar and came at them from the far side of the steering columb. I think the tricky bit is having a socket thin enough to fit in amongst everything. Mine was a halfords advanced set which worked perfect. I also disconnected the throttle cable from the pedal as that got in the way too. Then I just pulled it out. Check in the hole of the bulkhead for rust too.. There was a tiny bit on mine that I treated.

I'm sure that's pretty much it.. As Rob said it still a nasty job..

[Brianmoooore]

When the slave cylinder fails, the master cylinder piston is pushed that little bit further down the bore than it usually goes, into the ring of crud and corrosion that will have formed there over the years. This damages the lip of the probably already fragile seal, and results in its total failure a couple of weeks later.
Also, it's fairly common to find the clutch fluid on RH drive E30s resembling tar, having missed its two year change interval for the last decade. The old seals can handle this thick stuff, but when it's replaced by nice thin clear new stuff, it leaks past them.