Master cyl

[brian hood]

I am about to scream!!!

I used a rebuil kit on my Brake Master Cyl. I cant seem to get the brakes to bleed down. I am wondering if I might have put the valve (inside of the cyl) in wrong. The diagram I found on our site does not look like mine. Does anyone have a link or advice?

Brian

[alanhaley]

I am about to scream!!!

I used a rebuil kit on my Brake Master Cyl. I cant seem to get the brakes to bleed down. I am wondering if I might have put the valve (inside of the cyl) in wrong. The diagram I found on our site does not look like mine. Does anyone have a link or advice?

Brian

I just got done the same thing situation with my one ton. I pulled the cyl three times and bench tested it to make sure it was not the reason I could not bleed the brakes. Put the cyl in a vise, cap all the outlets and push with a large phillips or 3/8 rod of some sort. You should not be able to move the plunger if all is right. I went to a local parts store and had them make up a hydrolic line to replace the steel line that runs from the MC to the distribution block. This made it easier to connect up the ends but needs to bleed out on its own. You can do this on the bench or by holding it up in the air and have some one apply gentle break pressure. There is something about the rubber that really holds onto air bubbles.

I can tell you that after a dozen or so attempts at trying to bleed the system I ended up capping off every opening at the distribution block (the place where the line from the master cyl connects to the three lines) except one. I would then try and bleed that line. Once that seemed to be right, I brought in another line. In the end, it was a whole lot of tiny leaks that were the problem, even though I used new lines and fitting from front to back. A big problem area is the block arrangement where the line connects to the rear wheel brake cylinder, it does not take much for this fitting to suck air. I ended up lapping that block, carefully cleaning the two brass washers (there is a series of concentric grooves that you have to watch out for) and applying copper gasket spray.

I used a vacuum tester to bleed the lines but this did not work well and I would not recommend using it, i think it is too easy to pull air around the threads of the bleeding screws as they are so large. In the end, the only way I managed to get any brake was to have the daughter sit in the cab and push/pull the brake pedal.

Good luck, you are doing better then me as there were plenty of days in which I did start screaming.