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MG MGB Technical - Wheres my clutch fluid gone?

Ive come to start my gt after winter break and noticed the clutch pedal felt sticky. I looked in the master cylinder and all the fluids gone, i looked underneath and nothing not even a drop of fluid or a stain.

So firstly can the fluid go anywhere else?

Secondly should i replace the master and slave cylinders to be sure?

Also i heard its difficult to get to the rubber hose connections is this true.

Thanks
whiskeyfrank

There are only two ways out, normally. It either leaks out of the slave cylinder onto the floor, or it leaks out of the master cylinder and soaks into your carpet.

The third possibility is that it may leak out of the flexible hose, although it would need to be really perished for that to happen and it would still end up on the floor.
Dave O'Neill 2

Peal the boot on the slave cylinder back and see if the missing fluid is inside there (fourth possibility). Cheers - Dave
David DuBois

like detectives!!

David was right its all appears to be in the rubber boot of the slave cylinder, so whats going to need replacing?
whiskeyfrank

I don't believe that it is all in the rubber boot, there is just way too much fluid fo that to contain but of course some of it may be. I think that the master cylinder is faulty and that the vast majority of the fluid has seeped into the carpet. It may be difficult to detect now but I bet that is where it has gone. In that case you need to replace the master and slave cyls and the flexible and then bleed out the system.
Iain MacKintosh

Thanks, your right im thinking, im sure the carpet looks clean as it brand new, but must of gone somewhere.

Im going to replace the lot and see what happens, best to make sure i suppose.

Whats the best bleed method? Using an eazibleed and reverse bleed or connect to the brake nipple?

anyone done either?
whiskeyfrank

My Guess is that you did not check the level when you put the car away for its winter break, and it has been leaking away from the slave cylinder last year
and you did not notice the loss until this time round,
hence no drips on the floor.
My suggestion would be hone and re-rubber the cylinders first providing they are not to badly pitted, fit a new hose and away you go.
if you need new cylinders try
www.BGDevelopments.co.uk Bob Green was ex Girling
so very helpful.
Tim
Tim Hodgkinson

Hydraulic fluid evaporates, it doesn't sit there like engine/gearbox/axle oil.

If the boot of the slave is wet it almost certainly needs replacing, but may not be the only cause. It's a good idea to replace both slave and flex hose together, but the latter can be a real beggar with the engine in! A new slave cylinder will almost certainly have the thread start in a different place, so the flex hose would need slackening to prevent it twisting up at the very least. It is one benefit of honing the cylinder and replacing the seal and boot, if you can find someone to do it reasonably.

Having read of the problems people have had with top-down bleeding I've only ever done bottom up i.e. reverse bleeding, and it's a moments work. Even easier than an EeziBleed is simply to connect the clutch slave nipple to the RH caliper nipple, slacken both, then use the brake pedal slowly and gently to fill and bleed the clutch reservoir until you can see fluid, then top both off. There is enough fluid in the brake master to do this without running low,even with the metal single-circuit master, but keep an eye on it. No problem at all with the plastic dual systems. But before doing that, put some fluid in the clutch master and try pushing that out of the bleed nipple into a container to flush out any gunk from the pipe and hose.
Paul Hunt 2010

When my '64 B was leaking at the master cylinder, I replaced the master cylinder, slave cylinder, and hose. The slave cylinder and hose were easy to change because we put the car up on a lift. The master cylinder was another story. We pulled the rubber plug above the pedals. Since it was my car, I had the pleasure of working through the hole while my friend Larry worked in the engine bay. We needed to use some of Larry's special tools.

To bleed the line, I had brought my EZ Bleed, but Larry use the tried-and-true two-man method of push pedal, tighten bleeder, release pedal, open bleeder, etc.
Bill Barge

when my slave went I replaced job the job lot including the hose - low cost and piece of mind. loads of advise from on here re bleeding up. I found the best was for me was to clamp the slave closed and bleed it up before fitting to the slave to the box.
S Longstaff

Paul, with your method of using the RH brake caliper to push fluid through the clutch slave up to the master, do you find you can simply push the brake pedal gently to the floor, then slowly release it back, repeating until the fluid arrives at the clutch master cylinder? Is there not a problem with fluid (or air) being drawn back into the brake caliper when the pedal is on its upstroke?
Whenever I have bled my brakes, I have had a helper close the bleed nipple before letting the pedal up. Otherwise I found air would be drawn back into the caliper. But I gather this is not necessary when bleeding the clutch system this way?

The reason I ask is that the last time I had to bleed my clutch system, I had great difficulty. Tried the method in the manual, and Ezibleed both up and down (it was the up direction that finally worked, but even then it was very difficult). Your method sounds very slick and I'd like try it next time (I know there will be a next time someday!)

Erick
Erick Vesterback

A good point, Erick, and thinking back two of us were doing it and I'm sure I was saying "up" and "down" and closing and opening the bleed nipple accordingly. Probably best to close the brake (when bleeding the clutch) so as not to suck air in past the threads and pipe to nipple connection when the brake fluid pressure goes negative.

The only time I've opened and closed the brake nipple during *brake* bleeding is after doing basic bleeding with continuous flow from the EeziBleed. On three cars now I have found that leaves a long pedal that pumps up, and it needs firm pressure on the pedal while I rapidly open and close each caliper nipple in turn, which always blasts an extra bit of air out, even though it had stopped with the EeziBleed.
Paul Hunt 2010

Thanks for all the advice.

When I took the clutch master off it was leaking from the boot, and when I took it to pieces it’s totally written off inside, no idea why.

But also noticed the brake master was also leaking and as I have already rebuilt it in the past ive replaced both, also gave me an opportunity to take everything out from the engine bay corner and repaint.

I have replaced the lot apart from the flexible hose, which even with penetrating fluid (3 weeks worth) and crows foot wrenches, still won’t come apart.

Am I going to be stuffed putting the new slave on, or anyone have advice how to get the hose off?
whiskeyfrank

Take the engine out (only kidding). I had to fit a new slave and bought a new hose as well, but like you simply could not shift any of the nuts (annoying as we had just had the engine out for a clutch change!). I said we could grind the hose off the bracket, then pull the pipe down a bit and see if we could shift the nuts then, but could wreck the pipe. My pal wasn't keen and said leave the hose, but when screwing the new slave onto the old hose of course the thread had a different 'start' position which meant the hose would have been twisted when the slave was bolted back up. Fortunately a second copper washer put things into line.
Paul Hunt 2010

washer! the simplest things, never thought of that. what a star.

better get over to Ombersley to get some washers before the weekend then.
whiskeyfrank

This thread was discussed between 11/04/2010 and 12/05/2010

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