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Hydraulic Problems

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M

mxp01

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In July I my car to a friend while I was on vacation. When I returned the car was backed in my driveway, as if it was unloaded from a tow truck. The hydraulics weren't working, so I couldn't shift gears. He never admitted to anything being wrong and I didn't press it, I figured I'd just fix the problem and move on.

I've been waiting for my tools to arrive from the US, but after 6 weeks of delays I attempted to bleed the system myself. I worked all 4 brakes and then went after the slave cylinder. I really couldn't get a good grip on the bleed screw for the slave, but I think I bled that out as well. I noticed when I got under the car that the dust cover on the slave was torn and essentially not covering anything, and the same can be said for the dust cover on the clutch fork.

After bleeding I tried to run the car, but it wouldn't shift into gear and both pedals felt pretty flat.

I bought a Mitivac, but didn't have much luck with that.

I'm looking for suggestions/input/etc.
 
Do a search on clutch bleeding. It's one of those things that comes up frequently, because it's so difficult to get it right.

One problem is that the clutch slave cylinders invariably have the bleed screw in the lower hole, as in the picture below. It helps enormously to put this in the upper hole and the hydraulic line in the lower one, if it's not that way already. (I don't know if the cars originally came from the factory this way, but it's an interesting question.) The holes are identical, so there's nothing wrong with doing this. If you make the switch, you'll have to make a rather tight bend in the line, probably tighter than you can do with a bender, so this requires some care to prevent kinking the line. You may have to reroute the line a little, as the bend will take up some length.

Even then, the cylinder, in its normal position, is slightly tilted, with the bleed-screw end lower! Raising the front of the car might be enough to compensate for this, but I have always just removed the cylinder mounting bolts and made sure it was tilted so the bleed end was up.

I've always bled the clutch the old fashioned way: open the screw, push on the clutch pedal, close the screw, release the pedal. You can do this with one person if you access the bleed screw from the hole in the passenger side of the transmission tunnel.

If you've removed the cylinder for bleeding, be sure to put a clamp or something on the cylinder to prevent blowing the piston out. Some cylinders have a lock ring that does this.
 

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When I bought my five speed from Paul A. he sold me a flexible hose line for the slave. With it, I just held the slave above the m/c and the bleeding was quick and easy.
 
My bleed screw is in the top hole on my car.

I used speed-bleeders when I rebuilt all my hydraulics and I'm a fan now. The only issue I ran into with them was that I had to switch back to the original bleed screws to to the initial pull of fresh fluid through the lines. Once that was done, I put in the speed bleeders and was able to get a good pedal for the brakes and clutch with minimal fuss.

https://cgi.ebay.com/ebaymotors/MG-Midget...s#ht_1756wt_910

Bought mine off eBay -- not sure how hard they'd be to get where you are.

I was able to get a good wrench grip on the clutch bleeder through the little access hole in the RH footwell. Bleed screw is pretty much right there.
 
Guys:

Thanks for all the input. This is very, very helpful.

How about contaminated DOT3? I'm here in the tropics with high humidity. Is that a factor?

Can you also comment on the broken rubber seals on the slave and clutch fork. I need to place an order an figure I need to order these as well.

Mike Pennell
 
Yes, DOT3 will absorb moisture, but it will do that everywhere, even here in California. That's why you need to purge the brake and clutch fluid every year or two. But that's a separate issue; it won't affect anything else. It certainly won't cause the clutch or brakes suddenly to fail or let air into the system.

Of course, this raises a question that I should have asked earlier: hydraulic systems don't spontaneously get air in them. Usually that happens when the fluid level in the master cylinder gets too low, maybe because of a leak. Probably you should check around for something like that.
 
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