Rear brake not working

[m2pete]

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Thanks again Pieters86. My 3/8 was six-point. I bought a 12-point, and it works.

When I remove the brake line from the master cylinder and press the brake pedal, fluid comes out of the top, so I am thinking the master is ok. The fluid is clear. The only possible restriction seems to be the connection for the brake light switch (see attached). Anybody heard of fluid being stopped by this switch?

 

[Cooter]

Yes.

clear the line and banjo switch,

 

[m2pete]

Well, good news: I rebuilt the master cylinder with new parts, put everything back together, and filled the reservoir. Tried the old school method of bleeding the brake line by pumping the pedal and holding it down, opening the bleeder, closing the bleeder, then repeat. No fluid ever comes out of the bleeder and the pedal never gets hard, I think because the size of the master cylinder is very small compared to quantity of air that could be in the line? Is there a better technique, or do I need to purchase a pressure bleeder?

 

[Cooter]

the parts are still full of corrosion.

clear the line and banjo switch,

.

 

[Bueller-Bueller?]

I think your line is clogged. I would just replace it (amazon has lots of brake lines very reasonable) very least take it off and blow air it it. If the line is clear make sure the caliper moves.

 

[34nineteen]

Is fluid being pumped out of the master? Don’t worry about the bleed nipple at this point. You may need to “bench bleed” or “prime” the master first.

If a line was clogged, he would have a firm pedal.

If the master is not moving fluid, it doesnt matter what the rest of the system is doing.

The master is small enough where it’s not going to take a big air bubble to have the master (Baretts college nickname) “dry pump” (Cooters college nickname).

Start there.

Let me say it again.

Start there.

 

[Cooter]

Question for the OP.

When you "re-built the master", that included taking off the 90* plastic fitting that connects to the reservoir, Clearing that line, including the very tiny hole that feeds the master with fluid from the reservoir that is clogged with corrosion, and replacing that o-ring?

Your "rebuild" also included cleaning the fitting of the brake light pressure switch?

Disconnecting the brake line from the caliper and blowing compressed air through it?

We're trying to help you and now just guessing here, you're not doing such a great job of explaining what's happening.

 

[m2pete]

Yes, new 90 degree plastic elbow and o-ring, cleared the small hole, new piston and seals and spring. I think next step is try to force new fluid through the bleeder, after removing the line from top of master cylinder. If no flow, will remove brake light switch and one or more sections of line.