I have a '40 Plymouth P10 and am having trouble getting the Master Cylinder to get any firmness on the Pedal. It all started when I had a Wheel Cylinder go bad. I replaced it with a new one and hooked everything up. I filled the MC with Dot 3 fluid but, could not get any feeling at the Pedal. I then took the MC out and put a new Rebuild Kit in it. I put the kit in using the instructions from the Service Manual, bench bled the MC, re-installed it and made sure the MC was full. I was able to get oil to come out of every Bleeder Valve, but still was unable to firm up the Brake Pedal. OK! maybe I put it together wrong, so I took it out and dismantled the MC again and put it back together, in what I thought was the right way this time. Same results! My Bleeding procedure is; RR, LR, RF, and LF. The holes in the MC are clear and working. Any idea's would be greatly appreciated! Thanks!
I don't know if this will help you, but here goes. I just had a issue with a friends 35 ford with the m/c under the floor. We replaced the frond calipers and rotors, no matter what i did i could not get any pedal out of it. We pumped the pedal and bled, we used a va***n bleeder at the bleeder on the caliper, no go. We went through about 2 gallons of fluid and kept getting air bubbles. I finally decided that we had to do something else, I have a power bleeder that goes on the top of the m/c and forces fluid through the m/c and through the rest of the system. It took longer to install the bleeder setup than to bleed and get a firm pedal. It was a pain to get the bleeder plate on to the top of the master but it worked. Also make sure none of the rest of the wheel cyls are leaking, even a little will allow air back into the system.
So it was working perfectly for many miles then the wheel cylinder let go. Changing the wheel cylinder seemed to be the turning event. Are the brakes adjusted correctly? Blown cylinder usually means wet shoes, then new shoes and those new ones come in axles. Are the brakes installed correctly?
Good call on the brake adjustment, this helps to get a high and firm pedal. Which helps the bleeding as well. On a car of that age, if I find a bad wheel cylinder, I replace them all. One or more sluggish weepy ones also impact the bleeding. Check the lines and hoses, blow them out with brake kleen and compressed air. I like the power bleeder suggestion too, it will speed things up provided you can get it hooked up to an under-floor master.
If you install plugs in the master cylinder output (brake lines), Does it have a firm pedal? Another leaking wheel cylinder? Swelling hose or blown line somewhere? Are the brake drums on and linkage engaging the shoes correctly? Air trapped in line via air routing- use the vacuum brake bleeding system such as sold by Harbor Freight.
What kind of Power bleeder did you use cshades? After pulling all the Drums, the linings where dry. I can't find any leaks in the other Wheel Cylinders. I adjusted the Brakes according to the Original Manual. I am using the Harbor Freight "one man" vacuum brake bleeder. The bleeder holds pressure when pumped up but, when the Bleeder Valve is opened the pressure does not go down, I think it should go down if it is pulling fluid thought the lines. The brakes are installed correctly according to the Book. If there was a blockage in the lines or hoses, wouldn't there be no fluid getting to the WC's? I will try plugging the outlet from the MC. Thanks for everyone's input! Any other ideas? Please feel free to comment.
Have you tried conventional bleeding with a helper? Or just the vacuum bleeder . Fouled hoses usually show as brakes that won't release. The fluid flows to the WC under pressure but can't flow back.
I used a bleeder simular to branick BRNG300, I don't know what mine is exactly because i bought it about 25 years ago when i was fighting a 76 olds cutl*** that would not bleed. Hooked it up to that car done in minutes compared to the 2 hours i had in bleeding it already. It isn't cheap, you don't use it alot but the aggravation it saves at least for me is priceless. You can also use it for flushing brake systems. When you checked your other w/c s did you peel back the dust boots and make sure there was absoulty no fluid leaking? My 41 coupe kept getting air in the system with no visable leaks until i slid back the boots and there was a bit of fluid. If fluid can get out, air can get in.
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