I encountered a problem with the brake system on the TR Spyder I am near completing: I installed a new brake master cylinder, connected all the brake lines to the new front calipers and rebuilt rear drums (new steel lines, new wheel cylinders and new flexible hoses all around.) I bench bled the new master cylinder before the installation and began to bleed the system. I got about five pumps with my buddy opening and closing the right rear bleeder, when the pedal got hard and wouldn't pump any fluid through the bleeder screw. I removed the master cylinder and bench tested it. I could not get the piston to move so I brought the mc. back to the parts store and exchanged it for another new one.
I installed the new replacement today, after prebleeding it, and got the same result as before: five or six pumps pushed some air out of the right rear wheel cylinder bleeder screw and then the pedal got hard and no more air or any brake fluid would come out of the bleeder even though the pedal was depressed. I checked the left front caliper (nearest the master cylinder) and could not get anything out of that bleeder screw, even though the pedal was depressed. I used a vacuum pump on the left front caliper and was able to bleed fluid through from the reservoir through the master cylinder. But the pedal still only moves an inch or so and then stops. I haven't even attempted to bleed the right front or right rear brakes.
The system is disk front and drum rear. It is the old single circuit master cylinder (a tandem will not fit the TR without altering the torsion tubes.)
Has anybody had a similar problem? What was the solution? I suspected a faulty check valve on the first unit, but the odds are slim that the same problem would occur in the second new master cylinder. Any suggestions?
Jim
Webster Groves, MO
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