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T-Series 74 MG Clutch

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mirceme

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The clutch on my wife's '74 MGB just quit working.. no warning, just doesn't disengage the gears. I'm guessing that the master cylinder is low on hydraulic fluid. I have my handy Haynes repair manual which provides real nice exploded view of the whole system. My problem... I have no idea where to look for the master cylinder and slave cylinder and reservoir... /ubbthreads/images/graemlins/shocked.gif

I think I'm looking at the reservoir next to the brake hydraulic fluid reservoir /ubbthreads/images/graemlins/confused.gif is this right?

If that is the starting point, how do I find the slave cylinder?

Based on other postings and the manual, it would appear to be prudent to drain the old fluid, fill and bleed.

Advice to a true neophyite is appreciated.
 
[ QUOTE ]
I think I'm looking at the reservoir next to the brake hydraulic fluid reservoir /ubbthreads/images/graemlins/confused.gif is this right?

If that is the starting point, how do I find the slave cylinder?

[/ QUOTE ]

I believe you found the master cylinder. How's the fluid level there?

If you follow the pipe from the master cylinder down to the transmission, you'll see it connected via a hose to the slave cylinder, which is mounted down there. Check for leaks throughout.

It does sound like a hydraulic problem. Good luck, and let us know what you find.
 
Filled the reservoir and bled the system (I think) Clutch now works and I was able to take a quick run around the area.

The transmission shifts smoothly but I have to let the clutch out much further than previously before the gears engage. Can anyone tell me if this means there is still air in the system or if I am facing other problems.

By the way, I traced the system and wasn't able to find any indication of a leak. I bought this car in spring rather inexpensively but don't really have any sort of mechanical history on it. I never checked the fluid level in the clutch and I suspect that it has been neglected for a while.

Thanks in advance

Tom
 
I usually carry my MG guide around with me but not today. Anyway, if the 74 is set up like the later models, The Lockheed clutch Master will be found under the hood on the drivers side firewall. Mine has a plastic type cap on the cylinder reservoir (unscrew the cap to check for proper servicing).There is a significantly sized brass looking housing attached to the reservoir. The cylinder itself is located near these parts and is a series of rubber cups and a spring type setup. You can either rebuild the Master Cylinder with a kit or purchase a cylinder if that is required.
If you are low on clutch (actually-Brake fluid-DOT 4 or better) my experience has been that there should be some leakage. I have even had it leaking inside of the car over the clutch pedal in severe cases.

The slave cylinder is located underneath the car near the transmission on the drivers side, it should be visible from the underside (you may want to get the auto on Jack stands of some type for ease of access and can be identified as it has a rubber fluid type hose and there should be a bleeder screw (nipple) which may have a small rubber cap on it. Again there is a kit to rebuild the slave cylinder or a replacement won't set you back much.

If it were me I'd check the fluid level first, then drag the wife out to depress the clutch while somebody loosens the bleed screw to bleed any possible air out of the system. This may take a few clutch pedal depressions to accomplish. it will also allow you to observe the color of the fluid to look for possible contamination. The fluid should be a light straw color and be fairly clear (not cloudy) in appearance. If it does appear possibly contaminated a drain, purge, and fill is probably necessary.
Don't forget to top up the reservoir when bleeding is complete.
there is a (one person) bleeder kit available at most Auto Part stores.

It is a bit unusual for the clutch to suddenly quit shifting a clutch ususally wears out over time.

Good Luck
 
The extra travel in the clutch pedal is a result of your fine effort to service the system. By bleeding and removing the air the fluid is actually compressing properly and giving you a truer clutch pedal travel. In time you (or the wife) will get used to that effect. And in the future if the travel seems to weaken ever again you may suspect it's time to check for fluid servicing. Nice job on the fix!!!!!!!!
 
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