67 with non-power drums all around. Car had been sitting “for about a year” when I bought it. I first went through the fuel system with new tank, lines, fuel pump, and rebuilt the carb. Replaced the radiator (1/2" hole in the bottom tank) and flushed the system. One of the front drums was frozen, so ended up replacing all four wheel cylinders, front flex lines, rear flex line, master cylinder, front shoes with resurfaced drums, and sanded the rear shoes and scuffed up the rear drums. Pedal goes to the floor, but after about three pumps will be solid and hold. I used a pressure bleeder with 10psi and am able to get three of the corners to flow solid fluid, but the RR just keeps flowing bubbles. I’ve seen it flow bubbles, then clear up, then bubbles start flowing again. Today I tried gravity bleeding (although I did let the M/C run dry once, so I would expect additional air in the system), but it just keeps flowing air bubbles. I’ve got about 8" of clear tubing that I’ve attached to the bleeder outlet to direct into a jar in order to see what’s coming out.
I started with the RR, but with continued air, I checked the LR, RF, and LF, and they are flowing air-free. Only the RR is problematic. Between the pressure bleeding and gravity bleeding I’ve gone through about a gallon of brake fluid. Before replacing these parts, the M/C wouldn’t pump up, the wheel cylinders were gunked up, and the rear flex line was totally plugged. I’ll pick up another gallon of brake fluid tomorrow and continue gravity bleeding, but would appreciate any suggestions as to what might be going on. This issue just has me totally perplexed…
I’d try doing the flex line again. That copper washer thing can only be used once. If for some reason, you have to loosen and tighten it again, you need a new one.
Maybe just try another wheel cylinder as well. The part could just be flat out defective or have some hidden cracking, especially if rebuilt.
The cracking can also be at the bleeder screw, not just where the line goes in, also maybe not deburred.
It sounds crazy, but do you have a really high powered magnifying glass? …or just try another flex line and wheel cylinder.
I also suspect Air is entering the system, if only one corner is acting up, i think the m/c is fine. Go over the lines again starting from the distribution block on the rear axle going to the RR, also the hard lines, mine got pinched where it was held on by a clip onthe rear axle resulting dificulties bleeding the brakes aswell.
Thanks for the replies. After racking my brain on this issue, I vaguely recall having a similar problem when I replaced all the brake hydraulics on my F150 a few years ago. IIRC, when I checked the pedal it was all good with no air in the system.
Looking at some things last night, the RR bleeder fits fairly loose in the threads. I’m now thinking the air is getting sucked through the threads into the bleeder port. Also, I hadn’t fully adjusted the brakes, so that may be the reason I have to pump the pedal. I’ll adjust the brakes and go from there.
Adjusted all four brakes and have partial pedal, with a single pump to get full pedal. Pulled the RR bleeder screw and put a few wraps of yellow teflon tape on it. Fluid now runs solid with no air. I’ll drive it a couple miles to get the shoes fully seated, then adjust again. Should be good to go!