The subject : 1980 F250 4x4 , auto , 400M . Ok , recently my brake pedal is sticking when I apply the brakes ( not good) and I`m tired of sticking my foot under the pedal and pulling it back up . Does this sound like the booster thats going or the Master cylinder ? IF it is the vacuum booster , what are the years of trucks I can look for at the auto wreckers ? What years will fit and is there a HD booster I should try and find ? If it is the MC I know what to do with that
Thanks for any help


Jeff

 

Do you have the spring in the picture below that pulls the pedal back? By the way, if you find you do need a booster, good luck finding a used one. I talked to a yard and they said they wish they had a truck load of them because the demand is so high. I think I bought mine with the master cylinder for $100.00 from the parts store.

 

This started mid week so I`ve been busy working but today I`ll look to see if that spring is intact first . I know of a yard locally that has a about 10 Ford 250`s but they are 83 and up . Most of them had the boosters in them the last time I was there , one of my catalogs lists a different PN for post 83 and thats why I wanted to know how interchangeable they are . Thanks


Jeff

 

Ya my spring is intact and working fine so , replace booster or master cylinder ?



Jeff

 

If you can get one in the junkyard, I would get both and keep them together. That's why I bought them together at the parts store. I read in the parts manual that when you seperate the master from the booster, there is something that can slide out of place in the booster, and then the brakes won't work right.



Here's another thing you have to worry about if you seperate the booster.




The pushrod has an adjustment screw to maintain the correct relationship between the booster control valve plunger and the master cylinder piston. If the plunger is too long it will prevent the master cylinder piston from completely releasing hydraulic pressure, causing the brakes to drag. If the plunger is too short it will cause excessive pedal travel and an undesirable clunk in the booster area. Remove the master cylinder for access to the booster pushrod. Adjust to the following specifications:
1976: 0.880-0.895 in.
1977-81: 0.931-0.946 in.
1982-86: 0.980-0.995 in.
To check the alignment of the screw, fabricate a gauge (from cardboard, following the dimensions in the above illustration) and place it against the master cylinder mounting surface of the booster body. Adjust the pushrod screw by turning it until the end of the screw just touches the inner edge of the slot in the gauge. Install the master cylinder and bleed the system.

 

Franklin

Thanks for the help man . The problem dissapeared as quick as it appeared .



Jeff