disc brake conversion...

[tonpartain]

Preliminary info: my truck is a '72 f100...donor truck is a '74 f100

Two questions:

1. Do I need to exchange my original brake booster for the one from the '74?

2. The proportioning valve from the '74 is rusted out...do I need to find another '74 valve or can I use one from a later model f100/150? The master cylinders changed between '74 and '75 and also between '76 and '77 (as least it appears so if I'm reading the lmc catalog right).

[fordman]

i don't know why you would need to swap boosters. unless there is something about the disc brake master cylinder and the drum brake master cylinder that is different being that they both seem to be power brakes. the proportioning valve could be off any truck i would think. as long as its a proportioning valve and not a distribution block.

[FORDification]

The proportioning valve from any '73-'77 truck will work, those are the kind mounted on top of the steering box, just under the master cylinder. The '78-'79 trucks had theirs mounted to the back of the front crossmember. You could use that instead, but would require some brake-line fabrication to plumb it in.

As Mike mentioned, as long as your present booster is working fine, I wouldn't worry about replacing it. However, you will definitely need the disc-brake master cylinder, since they're different from the drum-brake version.

[tonpartain]

Thank yáll for the info. I will hunt up another proportioning valve tomorrow.