manual drum/ drum brake dual master cylinder conversion

[bobenhotep]

I have all of the stuff I think I need for this, but I want to know if the distribution valve is a must have (like on the 67-72 model), or does it really just operate the brake warning light? My plan was to use a manual 1968 drum drum master cylinder, replace the 4 way block with a t, then extend the rear brake line to the master cylinder and be done with it. If the block is a necessity, where do I get one?

[William-in-St George]

I'd check with the people at Master power brakes. You will need a proportioning valve that will keep the rear brakes from locking up. Most of the braking action is on the front brakes whether drum or disk. This is in the not hard to do box and you will be pleased with boosted brakes.

[bruceandersson]

The biggest reason for the valve is that it allows the other set of brakes to work if there is a pressure failure in the other one. It just happens that it also turns on the switch for the warning light.

[F100forever]

At a minimum you, may need to ad a proportioning valve on the rear breaks to be sure the that you can fine tune the rear pressure down to avoid the back end padding the front end in a panic stop.

What are your bore diameters in the master you have?

Also, do you have a residual pressure valve both front and rear? They should be built into the master if its a drum/drum. if it was for a disk, you can add a 2 lbs residual valve to hole brakes on just a touch to overcome springs at drum.