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MG MGB Technical - Air in the clutch canalisation


Since a few days, when I change speed, I have to push abnormaly on the pedal; one said to me I probably have some air in the clutch oil canalisation.
My car is an MGB 1968.
How is it possible for me (alone) to put this air out of the canalisation or of the cylinder ?
Excuse me for my cahotic English.
Thank’s for the response
Arthur

You can bleed the clutch system yourself but then you would need some kind of "tool" I've seen in the Angloparts parts guide. Basically its a bottle with fluid and a hose that comes up to the bleeding nipple.
Turn open the nipple and press the clutch pedal. Air will come out and fluid will be sucked in. Never tried it this way but it should work.
succes
Carl

In order for air to get in, there must be a leak
somewhere in the system. I would first check the
hose (most likely) and connections to the master
and slave cylinder for leaks.

If the hose is more than a few years ago, its
probably worth changing anyway (especially the
rubber ones.)

I use the gunson's eezibleed, which I suspect is
available in Belgium also. This uses air from a
tire for pressurization. It is also useful for
locating leaks. The trick with the eezibleed is to
not use too much pressure (15 PSI or less) to avoid
getting air bubbles into the system or blowing
a cylinder seal.
Ronald

OK, I saw the "tool" (Carl) and the "eezibleed" (Ronald) in the book of Anglo-parts; thank you both.

But :
1) where is the nipple in the clutch circuit ?
2) after the air goes out (and the oil in), when I close this nipple, the position of the clutch pedal must be down or up ?

thank's for the response.

Arthur

The bleed nipple for the clutch circuit is on the slave cylinder. You'll find it next to where the pipe attaches to the cylinder at the opposite end to the operating rod. If you look under the car on the right hand side on the gearbox bellhousing in the vicinity of the starter motor you should see the slave cylinder.
When I'm bleeding a system (clutch or brake) I always make a point of doing the last "close" of the nipple while my assistant (small child) presses the pedal down slowly. This avoids any chance of any air getting back in through the nipple.
If you're doing this the hard way (no eezibleed, but with someone to push the pedal) the sequence is: Open nipple, push pedal, close nipple, release pedal. Repeat until no air bubbles are seen, checking fluid level in master cylinder occasionally.
Tim Cuthill

First check the travel of the slave piston, it should be about 1/2" to 5/8" if there is no air present. If you have that travel then something else is wrong with the clutch. If the travel is less than that then something has caused air to get in which will probably happen again if you just bleed it.

The best way of using the Eezi-bleed is to put it on the slave with the system empty and fill it from there. Takes about a minute to fill the system and doesn't need bleeding. You don't need to touch the pedal. You close the nipple when you see fluid in the master cylinder i.e. before it is full and top up in the normal way.

The slave nipple should be above where the flex pipe connects, slaves seem to be shipped with the nipple in the wrong place and they are often fitted that way i.e. at the bottom which doesn't help bleeding.

If you have to change the master cylinder consider changing the slave as well. If you change the slave then change the flex hose.

Paul Hunt

Thank you to all

Now, I know what I have to do this saturday (under the car)


Arthur
Arthur

This thread was discussed between 11/08/2002 and 14/08/2002

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