I'm trying to determine if I should replace my clutch slave cylinder. There is slight surface scoring on the piston and some corrosion of the bore near the lip. I'm not sure if the corrosion is far enough in to allow fluid to leak around the seal, however.

(click for bigger)

This is the slave cylinder bore with the piston removed but the seal in place.


This is the slave cylinder piston.



The master cylinder is in a similar state, but the piston is in much better condition.

I've got photos of the ongoing project here: http://antichipotle.com/clutch.

The fluid itself was an awful greenish color, with some particulate deposits junking things up.

Delicious DOT 3 on the left, and something that looks like brackish coffee and antifreeze on the right!

I would probably rebuild the slave cyl since if it looses a bit of fluid you can change it with almost no bleeding. Just put a thin plastic bag over the master cyl cap and do a quick change of the cylinder. Then do a bleed back by pushing the piston back into the slave cylinder and close the bleeder. As far as the master i would only rebuild what appears to be a perfect bore. They are a pain to change and fluid loss in that area will affect painted surfaces. Bob

I'm guessing that brackish looking brake fluid was in your master cylinder? If so, you need to drain & flush everything until you've got clear brake fluid running to all the wheels.

If it's in your clutch, same thing - drain the system until you see clear.

I don't mess with rebuilding slave cylinders - for what little they cost (around $50.00), its not worth my time....but, if you want to rebuild it, so long as there are no pits in the cylinder, go for it.

I'm curious as to why you have a cup of DOT 3 standing there. You do know that you should only be using DOT 4 fluid, right? It is possible that a DOT 3 fluid will work if all of the original seals, etc have been replaced in your hydraulic system, but personally I wouldn't chance it and the DOT 4 is better anyway. DOT 3 fluid will destroy the original-type seals in british automobiles.

I use DOT 4 on my Healey, since I'm not certain all the seals in the brake and clutch system have been replaced, but I use DOT 3 on this car. I've rebuilt the brakes, replaced all the hoses, and had it on good authority that the clutch hydraulic system was also rebuilt; it seems it hasn't. Still, I don't think it was a failure of a seal. I'll replace/rebuild the cylinders while I have them out.

The linkage between the clutch pedal and the clutch master cyl. push rod has wallowed out, however. I can replace the push rod, but what do I do about the clutch pedal?

Here's what I mean:

Get a good used one.

Hmm, thanks. Ebay time.

I tried rebuilding the clutch MS and it didn't take. Big problem with an MG is that it is right over your feet. Yes I got a bath. I'd just save yourself time and money and replace. If you replace a MS it's a good idea to replace the salve cylander too. Or at least rebuild the slave cylander.

PS I use DOR 3 in my clutch system and it work fines but I'm very easy on a clutch.