MASTER CYLINDER BLEEDING

[Rob A.]

Can the master cylinder(original dual '67) be bled with a vacuum pump through the bleeder valves, or does the piston have to be pumped to expell the air?

[Brian M.]

Re: MASTER CYLINDER BLEEDING

Rob, I have been advised by the best that the bleeder valves are on the master cylinder are just for looks. Go with the piston method slow & steady. Then I prefer the vaccumn method. I have a Vacula which pulls fluid through the syetem. I have used it many times with great results. Good luck.

[Mike McKown]

Re: MASTER CYLINDER BLEEDING

Rob:

This is the way I do it. Get two short made up brake lines from your auto parts store with the appropriate line and fitting size. Screw the fittings in the threads on the master cylinder and take the other end of the line and bend it over down into the reservoir. Fill the reservoir over the top of the end of the lines. Start stroking the piston and continue until no air bubbles blow out in your master cylinder reservoir. When the air bubles stop, you are done. You can do this on the car or in a bench vise.

Might not be a bad idea to take the piston out of the cylinder and make sure the holes in the bore are not plugged with some kind of trash preventing you from getting fluid to the rear wheels.

[Rob A.]

Re: MASTER CYLINDER BLEEDING

I'll try that today.....thanks again.

[John H.]

Re: MASTER CYLINDER BLEEDING

Rob -

The "Help" section at the auto parts store will have a blister-packed bench-bleeding kit for about five bucks; you MUST get all the air out of the master cylinder bore first or it'll take forever to bleed the system. Bench-bleed setup with the "Help" kit looks like this.

[Harmon C.]

Re: MASTER CYLINDER BLEEDING

I have had that kit in the last few M/C I bought at Auto Zone. Lyle

[Rob A.]

Re: MASTER CYLINDER BLEEDING

John,

I got the kit and bled the master cylinder. I hooked up the plastic connector and clear tube where the rear brake line goes and fed it back into the master cylinder below the fluid level and pumped until the fluid had no air bubbles. I then pumped fluid into the connection for the rear brake line in the distribution block until it came out the rear bleeders. Everything is clear. It appears that the master cylinder is letting too much air back in after each pump to make any progress filling the lines and calipers. I even tried filled the distribution line that goes from the rear connection to the distribution block.