63_Brake bleeding challenge

[Steve D.]

I read the archives and have taken some comfort in knowing that I am not the only one who has had a difficult time getting a firm pedal. However, my good humor is being sorely tested. Here's the set up:

63 roadster, drum brakes, single (non power) master cylinder.
New master and wheel cylinders, new lines and hoses 2 years ago when body was off, car has not been the on road since then. I bench bled the master cylinder and with a helper used the pump and bleed method. System appeared air free at all wheels, but pedal went near floor. Repeated above process with same results. Purchased Motive Products Power bleeder and repeated process with same results. Bled master cylinder on car, plugged outlet to lines with blank, got a firm pedal. ( small success) At the 4 way brass fitting on the frame, I disconnected the line to the right front wheel and the line to the rear wheels and screwed in blank plugs. I then bled the left front and got a firm pedal. (another small success). I removed the plug for the right front and reconnected the line. I bled the right front, but then the pedal was back to soft, going near the floor (large failure). I bled again, with the bleed tube immersed in fluid and with the container raised above the bleeder to let the air rise. The tube was liquid filled with no air pockets in tube after bleeding. Again I got the soft pedal. As Bill Murray would say,"and then, depression set in". I checked for leaks and found none. The only thing left to try that I can think of is to replace the hose, in case it is ballooning even though it is "new" and not leaking.


Comments welcomed.

Steve

[Harry S.]

Re: 63_Brake bleeding challenge

Steve, you are correct, a 63 is a unique pain when it comes to brakes. If your using DOT 5 the pedal will be soft, no way around that.

Next, on a P/B 63 car there is an adjustment between the MC and the P/B booster that allow for pedal movement. I can not recall if the same adjustment is on a non-P/B car, take a look. You can always adjust the pedal under the dash.

When I redid my brakes I got two new bad hoses. Not a bad idea to change them out.

[James J.]

Re: 63_Brake bleeding challenge

Steve,
I also had a miserable time trying to bleed the system with a pump. I think I ran two bottles of brake fuid through the system with no success.
I finally had success when I used the bleeder tube immersed in a container of fluid. The container was below the bleeder though, not above as you described.
Good luck
James

[Harry S.]

Re: 63_Brake bleeding challenge

Steve, I also installed the Speed Bleeders on the wheel cylinders. They have a check-valve and make it easy for one person to bleed the brakes.

http://www.speedbleeder.com/

[Alan D.]

Re: 63_Brake bleeding challenge

Steve, the best way I have found as a finishing touch is to gravity bleed each cylinder one at a time. Add a hose and allow each to drain overnight (that's perhaps a little long however). Had a lot of trouble when I changed to DOT 5, but found one new cylinder leaking which did not show any signs of leaking until a few days out. YES pain in the . . .

[Bob R.]

Re: 63_Brake bleeding challenge

I had a lot of trouble bleeding the brakes on my 63 last winter. I did the same things you did. New brake lines, new wheel cylinders, new hoses. It took hours to get a firm peddle. We found several problem areas: Several of the steel brake line connections that seemed tight were leaking. It was just a weepand hard to see. If you used the stainless lines the problem with this is worse. We backed all of them off and retightned them. Start bleeding the brakes at the rar right furthest from the master cylinder and work your way closest. A couple of days after I thought I had it fixed I still found some fluid at the brass 4 way connector near the steering box. I think it just takes some patience and you will get it.
Good luck

[Jim L.]

Re: 63_Brake bleeding challenge

Bled master cylinder on car, plugged outlet to lines with blank, got a firm pedal. ( small success) At the 4 way brass fitting on the frame, I disconnected the line to the right front wheel and the line to the rear wheels and screwed in blank plugs. I then bled the left front and got a firm pedal. (another small success). I removed the plug for the right front and reconnected the line. I bled the right front, but then the pedal was back to soft, going near the floor (large failure).

Steve,

The procedure you've followed so far is quite logical and strongly suggests you've correctly bled the wheel cylinders. Time to look elsewhere for the problem.

I'd want to remove the RF brake drum and verify the brake mechanism is intact.... i.e. are the wheel cylinder push rods actually contacting the brake shoe webs, for example. Are the shoes correctly adjusted so they are contacting the drum when you press the brake pedal.

You didn't say if you are using DOT 5 fluid or not, but don't let that be a distraction if you are. When correctly installed and bled, DOT 5 fluid yields a rock hard pedal.

Jim