front brakes dont release
 

53 ford wagon, power brakes, disc up front drum on back.when i hit the brakes the front wont release, unless i crack open the bleeder screws or wack it a couble of times with the hammer.its a ford set up up front s10 in the rear.replaced both calipers, brake hoses, steel line from the proportioning valve to the t block that feeds the front wheels,mastercyl. i checked push rod lenght also. we did find that the m.c. piston touched the pushrod before the m. c. seated on the booster. so we anded a couple washers on the studs that the m. c. goes on and that made that right. BUT it still wont release. i can pump the brakes get out and open the m.c. and watch the fluid shoot up out of the bowl about a inch high for a minute.even after it does that the pressure is still there.the back dosent seem to be locking up just front. HELP PLEASE. KEN

RESIDUAL VALVE IN MC?
Mine were just doing this with my Wilwood stuff...after I blead them good it seemed to help. If that MC was not made for disc brakes it will have a residual valve in it that keeps preasure on the drum brakes to keep the springs from forcing fluid back to MC...you probably already know that.. :? just a thought in case you hadn't thought about that...that or MC is junk.

i had the same problems several years ago when i converted drum to disc ( front brakes) on my 69 camaro. i ordered a master cylinder set up with an attached disc/drum residual/proportional ..solved my problems.

i am trying to think of the company..i know they were from California and 55/57 chevys were their main service line..

i will think of it and post if it comes to mind.

try here.


http://www.mpbrakes.com/index.cfm