brake trouble

[truckmover]

i have a 02 f250 7.3 150000 miles
im having a brake hanging problem that comes and goes.
i have replaced all calipers and pads.just did the last one today thinking i was good and out on the test drive about 10 miles into trip the brakes started dragging agian. i pulled over with bottle jack in hand and checked all four corners and to my amzement they all had some brake pressure applied.
the question i have is any ideas on why? thanks for reading will check later

[97 golden stroker]

ya a valve i think that it is in the master cylinder but cant think of the name for the life of me. i will pull my school book out and check it but sounds like the valve that im thinking of.

[bigcountrysg]

Originally Posted by 97 golden stroker

ya a valve i think that it is in the master cylinder but cant think of the name for the life of me. i will pull my school book out and check it but sounds like the valve that im thinking of.

I believe your thinking of the porportioning valve. This valve supplies equal brake pressure to all the brakes. This is to prevent pulling or one set of brakes from locking up.

[truckmover]

i couldnt find a propotioning valve just the abs control module.
i had to beat the master cylinder loose to seperate it from the hydro booster due too corrosion. i wanted to test drive with one bolt holding together and loosin it up when brakes were applied a , to see if hydro was doing the appliction and went 20 miles and no problem. so ill try imn am and see when cold. maybe knocked something loose in hydro. maybe dirt in an oring or something.
thanks for replys.

[BuickLeSabre1960]

I'm going to say either clogged vent port or improperly adjusted pedal pushrod. Have someone press the brake pedal while you look inside the master cylinder reservoir (not directly, if it has air in the system fluid can shoot out when the pedal is released). You should see a disturbance in the fluid as the pedal is pressed, if you don't it is probably one of those two problems.

[jamstoyz]

check your slides on the caliper. just replaced mine from the same problem. passenger side on 2 of my trucks. seems like a common problem with these trucks.

[truckmover]

thanks for the help
saw movement in fluid when pedal stepped on.
i loosened the master cylinder bolts and tried to remove the master cylinder
and due to steel on aluminum the master cylinder was stuck so i took a rubber hammer and banged it free then reassembed it , went for a ride and no problem now. 50 miles and counting. fingers crossed. i figure some dirt in o-rings in hydro or master cylinder got knocked loose. i drained power steering and replaced fluid so maybe we'll be good
THANKS agian for replys