No brake fluid entering lines from new master cylinder

I'm rebuilding my 1966 CJ5 (9" brakes) after it's been dormant in my garage for 22 years. I replaced the dried up MC with one I bought from Walcks, and the two front wheel cylinders. I thought I'd bleed the system at that point. However, I am not getting fluid into the lines. I've using a vacuum bleeder and I can squeeze the pump handle all day and no fluid comes out. I put the vacuum pump on the MC single exit port (single reservoir; one exit to a 1/4" line). I withdrew massive amount of bubbles, until clear fluid. I thought that that was my problem...not having bench bled. But no. Nothing to lines after my under-the-jeep MC bleed.

Here's how the peddle feels. It depresses about an inch (presumably that's pushing the piston deeper into MC), and then the peddle hits a 'wall'. No soft peddle, for sure. Boom... peddle movement over with a slight push. I fiddles trying to adjust push rod, but nothing different afterwards. In fact, I couldn't figure out which direction to turn the push rod nut to shorten/lengthen the rod. I tried counter and clockwise; no difference noticeable one way or the other.

I hooked an independent line from the exit port leading to a jar of fluid, and fluid came out (as there was more in the glass jar afterwards; I'm working alone and couldn't watch the activity), so I feel that the MC is okay (but not 100% certain).

Also, my brake lights do not come on, suggesting that no fluid pressure is activating the light switch at the end of the MC. the wires are hot, 12V (but I'm assuming the switch is good; I'll probably remove it to test, and also that'll give me another chance to see if the brake peddle pushes fluid out that switch port.

Do you think that because I disassembled the front wheel cylinders (no fluid came out then when I disconnected the wheel cylinders), and because the brakes haven't operated for 22 years, that there is so much air in lines that I'll never evacuate them? But... why wouldn't the MC just push new fluid into lines filled with air and the wheel cylinder bleeders open?

Why don't I have a soft peddle (instead of a hard stop) if air in lines is the problem? But most important is why doesn't the MC push fluid into lines, esp. considering that I'm using a vacuum pump to draw it into the lines? This makes me suspect the MC....

Any suggestions out there? I hope so -- ronnie

 

Disconnect the brake line before the rubber brake line. It may be plugged.

 

I couldn't get any fluid through the rear rubber line on my 6 after it sat for a long time. That rubber line may have deteriorated inside. If the jeep sat dormant for as long as you indicate, I would replace all the rubber brake lines and wheel cylinders just as a safety measure. getting it to stop is far more important than getting it to go.

 

If you have a hard pedal and no fluid coming out it sounds like a plugged line or hose or as in my case a failed brake stop switch that plugged my tee with rubber.

I would disconnect rubber hoses from the metal line and see if your pedal would then push and get fluid through it

 

Also disconnect brake stop light switch and try the same

I would disconnect rubber hoses from the metal line and see if your pedal would then push and get fluid through it

 

Agreed. Nice to have them be able to stop even if it's not running! Sure sounds like a bad hose to me. I always gravity bleed my old vehicle hydraulics, usually because I'm working alone. Keep the M/C full, just set the top on (don't clip or bolt down) and loosen the fitting into the suspect flex hose. Should let fluid out after a few minutes. That way working alone you can watch for bubbles at the loosened fitting.

 

30 years. Had exactly the same problem, re-restoring my CJ2A. started replacing M/C, W/C and all lines. Problem was rubber hoses had swollen shut.


Fltfndr

 

I had a rubber brake line fail on my chevy 2500 that acted like a one way valve. fluid went in, pressurized the caliper, let off a slight bit then dragged until the fluid expanded and locked up the disk.

 

Thanks, everyone, for your suggestions to my troublesome MC/fluid issue. Yes, I must agree with the blockage hypothesis. You know... I would have already removed those front rubber hoses, but there is NO way I could disconnect it from steel lines going into the the four-way junction (distributor block) mounted above axle. I rounded one flare nut with a vice grip, and quit there. So, I'm ordering an entire pre-bent steel kit, the rubber hoses and will make it all fresh, so to speak.

I suspect I'll have to cut the steel lines at the junction block and then put the block in a vice or take to a machine shop to get the flare nuts out. This amazes me.... that flare nuts can bind with their 'sockets' like they were put in with Lock-tite. How can this be? It's only brass-like material inserted into similar. PB-blaster; Liquid Wrench, flame-thrower, etc. all useless against these brake line connections.

Also I will replace the stop-light pressure switch, as that could be a trouble spot as well. Thanks again, everyone. -- ronnie