Booster

BRTRIMMER

MEMBER
1984 FORD F-150

I have an 84' f150 the brakes work but after aplied the pedal fails to return and you have to pull up on it to unlock them, it was in the hands of my brother-in-law and was returnd to my sister as they are spit up so I am not 100 percent sure what was done to it.
I do know he put a rebuilt master cylinder, which may be the problom, I was wondering if I could be anything else

3 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Two possibilties, 1. Pushrod adjustment is incorrect, or 2. Booster is defective. How far down does the pedal go? An inch or two? Or all the way to the floor? Here is the pushrod adjustment tool...

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Wednesday, March 10th, 2021 AT 12:47 PM

BRTRIMMER

MEMBER
2 POSTS

All the way to the floor

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Wednesday, March 10th, 2021 AT 12:47 PM

MERLIN2021

MECHANIC
17,250 POSTS

Remove the check valve on the booster, thats where the vacuum hose plugs in, see if you can suck air both ways, if you can replace the check valve, air should go only one direction. If it tests good, have someone help you bleed the master, start with the pedal up, have helper step on the pedal gently, open one of the lines, any air come out? Now close the line, repeat until all air is out, on both lines, occasionally check reservoir, dont let it run out, Now bleed at the wheels, RR, LR, RF, LF until all air is out. Have a pedal yet?

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Wednesday, March 10th, 2021 AT 12:47 PM