front brakes dont release

[outlaw256]

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

[Tod74]

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.

[bjuice]

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.

[bjuice]

try here.


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