Clutching Problem

Octagon Newsletter June 1985

By Phil McOrmond

The Midget is now back on the road and all is right with the world even my wife is now talking to me.

A couple of weeks ago, I decided that it was time to put the MG back on the road for the summer. The car was exactly where I had left it in late October and it was running fine when I shut it off. I had no reason to believe that it would not fire up right away. I had, of course, fired it up periodically throughout the winter to ensure lubrication (and for the reassuring feeling of things mechanical around me) but I had not moved it: specifically, I had not used the clutch.

I started the engine, ensured that there was 85 lbs of oil pressure and allowed it to warm up a few minutes at idle. Upon pushing in the clutch, I found it rather easy to do too easy in fact. Since I may have forgotten the amount of pressure needed, I tried to get first gear. No luck it was not about to go. I tried turning off the engine and starting it up in gear it's a good thing I was some distance from the green-house as the car took a rather substantial leap forward.

No harm done, but the idea began to dawn on me that I had no clutch.

The most likely reason was air in the line. I reasoned that clutches don't fail for mechanical reasons while sitting in a driveway. Well they might, but it seemed like rather a strange coincidence. There was no sense of panic at this point as bleeding the clutch system was within my capabilities.

I borrowed my wife and instructed her in the details of pushing in the clutch while I buried myself down the passenger's foot-well through the access hole by the slave cylinder. I did not use the rubber tube into a glass jar, as is specified by the manual, but rather relied upon instructing my assistant (wife) on when to push. We recently had our second child via the La Maze method so there was no problem getting this straight! After a few minutes I was convinced that the problem was solved, but still no clutch! This was getting serious. I decided that there was some more serious problem with the hydraulics than just a little air in the system.

Now there was a decision to be made which end to do: slave cylinder or master cylinder? I felt that there were a couple of things to consider: first, that water runs down hill and second, that the more difficult cylinder to get at was the slave cylinder. Because of this I believed that water had entered the system and run down the line to the slave corroding it. This had caused it to leak air into the system or, alternately to break the seal inside, preventing the required pressure build up. What I didn't know was that slave cylinders leak where they do because there is only one seal and nowhere for the fluid to flow except past the seal. So I had ignored the first sign of a problem with a slave cylinder.

I obtained a rebuild kit and rebuilt the slave cylinder. Fortunately, no major corrosion was present (in fact the seal looked pretty good). The kit went in well with a good fit. Upon re-installation and bleeding no clutch! The situation and my mood, were deteriorating rapidly. What was left.

At the April meeting I talked to Bob Hughes about my problem. He suggested that it sounded like the master cylinder and pointed out that the slave cylinder was an unlikely choice. He also suggested the Repco kits were a lot cheaper than the BL parts.

I bought a Repco kit (not at Sports Car Classics) for the year and make and discovered that it wasn't even close to fitting the internals to my master cylinder. Off to Sports Car Classics with pieces in hand ... no way was I going to get the wrong parts this time and I resolved to spend the extra money for the other kit. I discovered an interesting thing my car is a 1969, but I have 1974 pieces inside my master cylinder quite a different type of kit but this was remedied and all pieces were installed without a hitch. If anything, the master cylinder was in better shape than the slave cylinder, so I was somewhat doubtful that it would make any difference and I was right NO CLUTCH!!

I was really worried now, wondering how to solve the problem. I considered taking out the engine but I reserved this as a last resort after all else had failed but I didn't know where to go. I definitely needed help!

I phoned the Pickerings and sought the advice of John and Mark. After listening to my tale of woe, John thought that I had checked everything and was as puzzled as myself as to why there was no hydraulic action.

I started a little detective work where was there pressure and where was there not? The system had to be isolated perhaps I had put the seals in backwards in one of the cylinders how to check without disassembly? To check the master cylinder, I put a bolt into the outlet to seal it completely the result was a rock hard clutch pedal, no give at all, therefore the master cylinder must have been 'OK'. (A bolt that fits the outlet hole in the MG is the same size as the ones used to plug the pollution holes in the head, so most new cars have a ready supply of appropriate bolts.)

The slave cylinder was then removed, plugged (with the same bolt) and put in a vice with a rod placed to push in the cylinder. Again pressure was very good. Upon re-installation of all the pieces NO CLUTCH !!!

Now what? Sell the car for scrap? Commit suicide? Take two weeks holidays and try to sort it out? Take out the engine? Call Bob Hughes? Definitely. I called Bob. I explained what I had done and he thought that it still sounded like the master cylinder. To back it up he kindly lent me a used cylinder to put in (which of course had worked when he took it out). I felt this would confirm one thing at least that the master cylinder was 'OK'. The result of putting in the master cylinder Bob had lent me resulted in NO CLUTCH! Obviously, the master cylinder I had rebuilt was 'OK' and I thought perhaps the slave was also 'OK' as it didn't leak and had checked out in the vice.

The only thing left was the line connecting the two cylinders. I had a spare flexible hose for the lower part, so I used it and capped off the line just before the slave cylinder. The result of this was no pressure at all with the clutch pedal.

The line must have been the problem all along perhaps a bad fitting was allowing air to enter. I didn't know but I thought it would be a cheap fix. Was I wrong twenty-five dollars to have 55 inches of clutch line made up. Because of this I wondered if perhaps reversing the line would help. I reversed the line and in so doing I bent it quite considerably, taking a large hump out where the line passed over the heater. Perhaps this high hump would not clear of air? In any event, after the switch the clutch had pressure. Eureka!!! almost!

After starting the car, the clutch still wouldn't disengage. Now what? In reading the manual there was a note about rust on the spline shaft. How to get it off?

The answer was to put the rear axle up in the air and to run the engine in gear while working the clutch.

So, finally after about three weeks, the Midget is ready for the road. Many thanks to Bob, John and Chris for listening to my sad tale and in helping me work through this clutching problem. What's a club for anyway?

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