53 ford very low brake pedal

[larryabbott]

Greetings, my '53 has an upgraded booster and dual master cylinder.  The drums were inspected and said to be OK.  However, the pedal goes almost to the floor, to the degree that the left foot can barely fit under the pedal.  Pumping doesn't seem to help.  Is it possible that the reservoir is too small and that therefore there is not enough brake fluid?  Or could the rod be too short?  

 

If a bigger reservoir is called for, what would be the way to go?  Thanks for any suggestions, Larry

[19tom40]

I doubt if the reservoir is your problem. Low pedal is usually caused by adjustment or air in the system. If you adjusted the brakes and bench bled the master cylinder before installing it and then bled the brakes, you can assume that you don't have the usual problem.

 

With the engine off, pump the brake pedal to see if you can get a good pedal. If you can get a good pedal, let the brake pedal rest for about 10 min and try the pedal again without starting the engine. You should have the same pedal as before. If you don't, check the brake adjustment.

 

If you don't get a good pedal, check the pushrod to master cylinder adjustment. If the adjustment is correct, you may have the wrong size master cylinder piston. This means that you don't have the correct size master cylinder.

 

If you get a good pedal without the engine running, press on the brake pedal and start the engine. The brake pedal should not sink more than 1/2". If it does, you have a booster - master cylinder mismatch.

 

 

 

[larryabbott]

Thanks for reply and advice. My fault for not checking sooner.  Had MC bled today and shoes are in proper adjustment.  So, problem appears to be what you mentioned.  So, I'm thinking to replace complete unit.  Do you have any recommendations for best kit?  8" diameter, thanks, Larry