1967 Pontiac GTO peddle to the floor

1967 PONTIAC GTO
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GOAT 67
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Brakes problem
1967 Pontiac GTO V8 Two Wheel Drive Automatic

my peddle goes to the floor il pump them they go back to normal. Il wait or drive then they will go to the floor again.There is no visiable fluid leaking..
Mar 21, 2009 at 8:48 AM
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MMPRINCE4000
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You can try bleeding the entire brake system, front and rear (do not let the MC fluid level run out).

If problem persists, and there are no hydraulic fluid leaks, then replace the Master Cylinder and bench bleed it before installing on car.
Mar 21, 2009 at 8:57 AM
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GOAT 67
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thanks, but how do you bench bleed the master cylinder..
Mar 22, 2009 at 9:32 AM
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MMPRINCE4000
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Put MC in a vise (not too tight). Either plug the outlet ports or buy a bleeder set that connects to ports and directs fluid flow back to resivoiur (spelling).

Fill MC with new brake fluid, use large screwdrive and push on piston (NO MORE THAN 3/4 of an inch stroke) until all air is out of MC and only clear fluid pumps out.

If you plug the outlet ports push piston (3/4" stroke) until all air bubbles disappear.

This prelubes the MC seal and prevents the seal from coming in contact with dry bore causing seal failure.
Mar 23, 2009 at 6:49 AM