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I have completed the installation of re-built T-arms and re-installed the rear calipers. I started bleeding the rear calipers at the RR outer bleed screw. Using a borrowed pressure bleeder at 15 psi, I attached a piece of tube to the bleed screw, placed the other end in a plastic bottle, and opened the screw. I got a reasonable amount of flow of old fluid and air bubbles, followed by clean fluid. Now the problem; going to the inner bleed screw, I get barely a trickle of fluid and then nothing. Went to the LR caliper at both screws and again, a slight trickle, then nothing. Disconnected the pressure bleeder and tried the pedal pump method, same thing from all four bleed screws. The brake pedal seems somewhat firm and the rear pads are making enough contact that I cannot turn the rotors by hand, but I am puzzled by the lack of flow when I open the bleed screws. I did not change the flexible hoses nor re-build the calipers as these were done five years ago. Any advice would be greatly appreciated.
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Re: '69 Brake Bleeding Problem
Would think one on the brake experts would of replied by now. With what you have written I would start at the master cylinder. If its original it will have bleeders on the left side to bleed. Want all new fluid in the master cylinder about every two years anyway. I would them open a line, but not remove it and press on the brake pedal to ensure the master cylinder is moving fluid out to the line connection. If all is a go with the master cylinder I would remove the brake bleeder valves of one side and and insert a wire to break up any possible blockage. Install both bleeders and tighten one and see if the caliper will bleed fluid. Same procedure on other bleeder with the previous one closed. If the caliper will still not pass fluid you could remove the supply brake line if you have something to block off the supply connection, then using a leverage type tools try forcing against the pad ends to push the two pistons back into the caliper half with the bleeder valve open and see what you get. This is not a proven method to solve your problem as I have not experienced your problem with my 68 and 70. -
Re: '69 Brake Bleeding Problem
Jim,
Thanks for the response. After thinking about my dilemma over a few cold ones, I realized the possibility that my problem may be self-inflicted. See if this makes sense: During the re-build of the t-arms, I clamped off the rear flexible hoses with vise grips in order to stop the flow of fluid when I removed the calipers. I have used this clamping method for 30+ years when doing brake work. However, unlike other jobs in the past, the vise grips were on the flexible hoses for over one month while the t-arms were out for re-build. Perhaps the lengthy clamping period has collapsed the inside of the hoses and is preventing strong flow? Does this sound logical?Comment
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Re: '69 Brake Bleeding Problem
Is your brake 'warning' light on? If so, you will need to re-center the piston in the distribution block (the piece usaully mis-identifed as a proportioning valve).
MikeComment
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Re: '69 Brake Bleeding Problem
John,
Sounds to me like you have identified the problem. It is common for the flexible hoses to deteriorate internally and act as one-way, or check, valves. I think you will have to replace the flexible lines to cure your problem.
It is too late for you now, but there are special locking pliers made just for clamping off brake lines. They have rounded jaws, rather than the flat jaws of standard clamping pliers. I doubt even the rounded ones are intended for long-term use, however.TerryComment
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Re: '69 Brake Bleeding Problem
I have had good luck using the little nipple gizmos that you see on unused carb ports to stop leaking brake fluid at hose ends. I have saved a group of these over the years and simply find the right size to snuggly slip over the end of the brake hose or hard brake line.
Roger
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