Hi guys. I'm new here to the world of Fords but not to the automotive world so please forgive me because I do not know all the ins and outs (tricks) of Ford trucks.
The problem I'm having is that the front brakes on my father's in law 1975 F150 (5.9) 2WD keep locking up after driving it a couple of miles.
Here is what I've done so far.
1. Replaced the brake booster because of it being rusted out and causing a vacuum leak making the truck run like crap.
2. Replaced the master cylinder because it was full of rust and scale.
3. Replaced both front soft (rubber) brake lines because they were old and deterating, thinking they were causing a blockage.
4. Replaced the driver's side front hard break line because the end broke off while trying to remove the soft (rubber) line.
5. Replaced, cleaned and greased both front calipers.
6. Replace the proportioning valve thinking it was defective and full of rust and scale from the m/s.
7. Bled the crap out of the system.
None of this help much except the proportioning valve which seemed to delay the locking up of the front brakes.
Now I'm thinking(wondering) if there is an adjustment with the plunger that is between the brake booster and the master cylinder.

What am I doing wrong or where do I go from here? Any help or advice would be greatly appreciated
Thanks,
Robert

 

Sounds like you are doing a good job.

There is an adjustment for the booster rod. It is absolutely mandatory for clearance to be between rod and master cylinder piston. .050-.060

The pistons in the calypers can also drag, might check out NAPA for there calypers, pads and all for not much more than just the pads.

 

Bill,

Thanks for advice and clearence spec. for the booster rod. I will be going there tomorrow to check and adjust it. By chance how much adjustment is in the rod, or do they make different length rods?

 

Not sure of adjustment availabe, if any replacement parts have been intalled prior, would assume they would match for installation. Saying that, remember its Ford parts only for me, no aftermarket. Headaches and questions only arrise later if gypos have been used.

 

Bill,


If there is no adjustment, I just I will be on the hunt for a different length rod, that or modifying the current on if one is not available. I will keep you posted.

On a side note, do you have any recommendations for getting a snake out form under the dash? While my father in law were out for a test drive he started freaking out because a head of a rather large (hopefully) black snake stuck its head down right in front of him. Needless to say we were in a hurry to get the truck home and vacate the truck for a little while.

Again thanks for your help.

 

You guys actually drove the truck with the snake in there, BRAVE SOULS!

 

Check the back brakes for proper functioning, if you back brakes do not work it can lock up the front tires rather easily.