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MG MGB Technical - Clutch stopped working

I was drving along and tried to change gear and the clutch didnt appear to be working. I stopped and after a few minutes managed to get it into gear and get home. Anyway there was no clutch pressure. Not knowing waht to do I bled the system and topped it up. Now it still doesnt work and the clutch is really hard to push and then looses all pressure. When you pumpo it it gets really hard again and so on. It appears to be leaking now down at the bottom unit where the bleeding bolt is but not out of there. Anyway thoughts ?
Peter

When you top it up and bleed it, does the slave cylinder pushrod move at all? Have a helper push the clutch pedal while you watch the slave cylinder. The pushrod and the clutch fork lever should move 1/2 to 5/8 inch. If the pedal is hard and the pushrod is not moving, it is something "upstream".

One of the "usual suspects" with any sudden clutch failure is the hose. Its made of rubber, so it deteriorates over the years. It can fail internally and cause a blockage, while showing no external signs of failure. If you haven't replaced it in a few years, or if you don't know when the PO replaced it, go ahead and replace it. They're not expensive or particularly hard to replace and they *do* fail. Its like a fan belt: it should be replaced every few years, anyway.

Any signs of a crimped hard clutch hydraulic line in the engine bay?

Lastly, there is the clutch master cylinder.

My guess is that its either the hose of the slave cylinder, or both.

While you're at it, check the pushrod. The hole, where it attaches to the clutch fork can become quite oval-shaped. This will cause problems. Simply replace the pushrod and the clevis pin that attaches it to the fork.
Paul Noble

This thread was discussed on 08/04/2003

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