1941 ford brakes

D

dccis9@hotmail.com

Junior Member
As I DRIVE MY CAR ALONG THE BRAKE SYSTEM SOME HOW BUILDS PRESSUE i THINK. aT ANY RATE THE BRAKES APPLY THEMSELVES UNTIL i CANT CONTINUE. IF I STOP I CANT GET GOING AGAIN.THE BRAKES ARE ON FULLY AND THE BRAKE PEDAL IS TOTALLY STIFF WITH NO PLAY AND THE BRAKE LITES ARE ON OF COURSE. IS IT A FALTY MASTER CYLINDER PERHAPS THE PISTON IS STUCK? THANKS
 
Make sure the MC piston comes all the way back to the snap ring when the pedal is up. Also require approximately 1/2" free play at the brake pedal. If you don't have any free play, the MC piston can not return all the way. If all this is OK, you could have a plugged compensating port or a swollen primary cup (which would fail to uncover the compensating port on full brake release - pedal full up).
 
Because this is where the smart people are.. including yourself..... and including the entire Ford Barn Master helpers... He is looking for help from all sides... on the entire site..... Thanx for helping him...
 
So the snap ring is at the same end as the pedal and spring .So when the pedal is up the mc bowl is virtually empty of piston . Have I got this correct. The snap ring is at the end of the mc facing the dash board. Sorry to be so dum .no diagrams. thanks so much for your help. Dennis
 
Yes. Pull the rubber dust boot back to see this snap ring - it prevents the piston from coming out of the MC cylinder bore. By bowl, do you mean reservoir? The reservoir must have brake fluid (DOT 3 rating [DOT 5 is silicone and used only in a system designed for it - do not mix the two]) no other liquid will do. If perchance a solvent has been added, the primary cup (and every other rubber component) will be swollen and preventing the primary cup from uncovering the compensating port. Let's hope this is not the case.
BTW, this is for all car nuts: Auto Service and Repair by Stockel is an excellent book that should be in the hands of all vintage car DIY's. Out of print now, if you see one at swap meets or yard sales (or any where else - Amazon?) BUY IT! It explains each mechanical component and then has an easy- to- follow trouble-shooting guide for each system in the car.
 
There are usually 2 holes at the bottom of the master reservoir. One is a vent the other is the supply port. Both must be cleared by the piston when it's retracted/off. Now: if you haven't recently done any brake work and this started on it's own here's a number of things to check/do. Is your brake pedal free/not binding from rust or whatever and releasing fully? Did you add non-compatable brake fluid to the system? The newer stuff can react with the old style rubber components causing them to swell
& bind. If that's the case a rebuild or replacement & system flush is necessary.
 
ok I will check to see that the piston comes all the way back . I have not added dot5. I will also make sure there is 1/2 inch play at the pedal when not in use. Thank you. Love my old 41.
 
I had this happen many years ago after having work done on my brakes. Don't remember any more if it was a Ford or not. What happened was that the linkage between the brake pedal and the master cylinder had no play in it, so each time I applied the brakes the pressure on the brake fluid was not being completely released, and the brakes eventually stayed applied. Putting a little play in the linkage and master cylinder piston cured the problem.
 
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