jcox04 Posted January 27, 2019 Report Share Posted January 27, 2019 I have been slowly restoring my 53 for several years. Close to finishing but power booster is not cooperating. I have replaced wheel cylinders, flex hoses, brake shoes and rebuilt master cylinder. When I drove car around the block the brake pedal travel kept diminishing and brakes tightened up. Car would still move under power but brakes were tight. When I shut off vehicle brake lights would stay on for about 10 minutes (pressure switch). Next day pedal had normal travel but again moved up with several pumps of pedal. I found a rebuilder on ebay and had unit rebuilt. About a year lapsed as I had family issues to deal with. Upon installing new unit and bleeding brakes I still have the same problem. I tried disconnecting the vacuum line to unit, but still have the same tightening issue when the brake pedal is applied several times. I tried contacting rebuilder with no success. My next move is to bypass the booster, however if I remember correctly, there is a return line from the booster to the master cylinder? I'm open to suggestions Quote Link to comment Share on other sites More sharing options...
Greg51T&CWagon Posted January 27, 2019 Report Share Posted January 27, 2019 If you disconnected the vac line and still had the problem my money is on your MC being the fault. Not releasing pressure. pedal travel , assembled wrong, something there.. 1 Quote Link to comment Share on other sites More sharing options...
kencombs Posted January 27, 2019 Report Share Posted January 27, 2019 most commonly, that is caused by lack of clearance at the pushrod from the pedal. The piston doesn't completely uncover the return port. 1 Quote Link to comment Share on other sites More sharing options...
jcox04 Posted January 29, 2019 Author Report Share Posted January 29, 2019 Appreciate the information. I will investigate, thanks Quote Link to comment Share on other sites More sharing options...
captden29 Posted January 29, 2019 Report Share Posted January 29, 2019 the return line to the master is only for any fluid that gets past the diaphragm in the booster. capt den Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted January 29, 2019 Report Share Posted January 29, 2019 A faulty/failing frame mount booster can suck your master cylinder dry before you realize where that huge cloud of white exhaust smoke came from....and then...... zero brakes. Quote Link to comment Share on other sites More sharing options...
jcox04 Posted January 31, 2019 Author Report Share Posted January 31, 2019 Update; Incorrect master cylinder repair kit. The piston is too long which is blocking the return port. Just ordered new one. Thanks for the help, the old style brake booster was the focus of my attention, should have thought of master cylinder when I plugged vacuum line and problem persisted Quote Link to comment Share on other sites More sharing options...
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