Saturday, November 18, 2017

Clutch Master Cylinder

I've been dealing with various clutch related issues and the last (hopefully) being the replacement of a leaking clutch master cylinder. The old one was throwing fluid into the footwell every time the clutch was depressed.

The original Jaguar part number is C27186 and the part is still readily available from many of the usual suspects and costs anywhere between $50 to $100 (even for a genuine one).

I wanted a replacement quickly and that meant ordering it from XKs Unlimited. Being only a few hours away from me, shipping is very quick and cheap. Unfortunately XKs Unlimited doesn't sell a like-for-like C27186 replacement. Instead they sell a more universal part GR64068754 which was only $33.84. It is also sold under the more generic use part PMD239X.


Only issue (and the reason for this post), is that you need to transfer all the fittings, including the push rod over to the new one. And its not easy.

The easiest thing is the fluid inlet fitting. Its a straight swap. The new master cylinder comes with a fluid outlet fitting, but it needs to be removed as it doesn't fit the hard line on the car.

The complication arises when you need to swap over the push rod. Removing the old push rod is a bit difficult. There is a metal collar that holds the boot and obscures access to the circlip that first needs to be chiseled off. Once the push rod is removed, the trapped washer on it won't fit into the new master cylinder. It needs to be lightly sanded down around the edges. Make sure its loose enough to slide past the circlip recess in the new master cylinder.

Now the delicate part of transferring the new rubber boot. It slides off the new push rod easily as there are no restrictions but the old push rod has the integrated fork for the clutch pedal. I managed to push the old push rod through the new rubber boot, fork side first. It is possible but it can easily tear if you're not careful.

The new master cylinder also has a wide black rubber band over the boot to hold it down tightly. This band (as shown transferred over in the photo below), cannot be used and should not be trasnferred over as it will prevent you from installing the master cylinder into the car. Which I later discovered when trying to bolt it into the car.


Make sure to use new copper crush washers and clean up the sealing surfaces of any old parts being transferred over.