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MG MGB Technical - Clutch Bleeding

1973 MGB
I have pumped, sucked, blown and still cannot bleed the clutch sufficiently to produce adequate pressure to operate the clutch.

Any tips ?
Does anyone have a good cross section of the master cylinder to check with cups are right way round ?

Regards
Exceeding despondant and frustrated
Bruce

I've heard stories of old hoses developing "flaps" on the interior which under pressure --- positive or negative, can act as a check valve.

Other than that, you might try sacrificing a cat.
Dan

Bruce - After bleeding using the normal routine, close the bleeder screw on the slave cylinder then, by hand, push the actuating rod and piston all the way to the back of the slave cylinder. Rebleed the system using the normal routine. You may have to repeat this a couple of times, but it should solve your problem as long as there are no mechanical problems with the clutch or hydraulics. This method pushes any air remaining in the slave cylinder back into the line going to the master cylinder and rebleeding the system then expels the air through the bleed screw.
Good luck - Dave
David DuBois

Cup shaped seals in master and slave cylinders are always the same way around.
With a tapered seal the smaller diameter faces the pushrod and the larger diameter faces the fluid.
If you had them the wrong way around you would be getting fluid leaking rapidly at the pushrod. No leak, they must be correct.

Mick
M F Anderson

The absolute BEST way to bleed any hydraulic clutch is by using a 'pump oiler' You know the type used to oil those little cups?
You must flush all oil out with first brake cleaner, then fill with brake fluid. Pump until it's pure fluid. Now find a preferably clear hose that fits the slave bleeder and the end of the oiler. fill the master cylinder reservoir about 1/2 way, cover with a shop towel [rag] Open the bleeder, push the hose on, and pump anywhere from 10 to 20 times. Close the bleeder screw, top off the reservoir. Now try it. If it's still not working, you have a failure in the mechanical side, or the hydraulic's.
Dwight
Dwight McCullough

The best, easiest, and cheapest way I've found to bleed the clutch is to run a perfectly clean tube from the bleeder valve up into the reservoir, crack open the bleeder, give it a few pumps to get some fluid out of the resevoir, top off the reservoir. You want the reservoir to be pretty full and the tube to be full of fluid. Then start pumping the pedal. The air bubbles flow out through the tube, up into the resevoir where they stay in the reservoir and pop thus staying out of the hydraulic system. Keep doing this until all bubbles are out and you're just circulating bubble free fluid - takes me about 30sec. of pumping.
Good Luck, Wade
Wade Keene

This thread was discussed on 15/03/2003

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