I have a 67 f100 that I recently converted to disk brakes from a dent side. Used dual piston.

At the moment I'm using the stock proportioning valve and master cylinder.


As of today, my MC went out and I'm gonna pick up a new one from the parts store tomorrow


What should I use? Stock 67 style for drums or a late 70s style for dual piston calipers?

 

use a disc brake MC.

without going into a lot of detail: drum MCs and disc MCs aren't the same internally.
Master Power Brakes - Reference/FAQs: Master Cylinders

really, you should have switched MCs when you put the discs on.

 

You were not recommended that swap here. Where did you find dual piston half ton discs? Those were on the larger trucks.

If you are going to run disc-drum setup, do it right with all the correct parts. You need the porp. valve from the donor truck, the discs & drums are different aminals, with different requirements.

Everything needs to be from the correct set. BUY A DONOR GET ALL THE CORRECT PARTS GUYS!


John

 

Good info!! Thanks for posting.

 

X2 for all the advice that has been posted. Master cylinder and prop valve parts for drum/drum and disc/drum systems are system specific. They are not meant to be interchanged.

 

It has 3/4 ton stuff on now, 8 lug.

I just finished the truck the other day

I have the new pro. valve too just haven't made new lines to put it in, and everyone said I don't absolutely need it, even though I'm going to and I'm aware im not getting full potential out of the disks

And I wasn't aware of the different MCs, truck stopped great the past few days but just randomly went out.

But looks like I'll order one for a 73 f250 with dual piston calipers.

 

"everyone said I don't absolutely need it" I guess everyone else was wrong. Glad you came here for the facts. You would have had real fun to bleed the rear brakes with out the prop valve.

 

delete.. double post

 

it makes it hard to bleed the rear brakes? the original one is on and brakes worked fine for a few days untill the MC went out.

 

Bro, I don't know why you would mix your parts like that. F250 discs on the front with F100 drums on the rear is a scary thought to me.

I am going to stand down, and let yall figure it out.



John

 

I'm not mixing parts. I have a 8 lug dana 60 rear. Truck has full 3/4 ton suspension and drivetrain. And just picked up and new MC and putting the prop valve on.

 

All is good then!

 

No prob bro, all I have is what I read in your first post: "I have a 67 f100 that I recently converted to disk brakes from a dent side. Used dual piston."

I'm sorry, what has been talked about does not apply to a F100.


John

 

A drum/drum system does not have a proportioning valve. It has a distribution block, which basically just distributes fluid to the brakes on one side of the system or the other.
A disc/drum system has a proportioning valve. A proportioning valve will alter the fluid pressure to the front and back, as they have different pressure requirements.
You CAN use a distribution block on a disc/drum system and get away with it..... until you have to make a panic stop. Then you will wish you had the proportioning valve.
Bottom line: Never use a distribution block on a disc/drum system!

 

Usually, 10 PSI residual for discs and 2 PSI residual for drums.