I am going to convert to a new style master cylinder on my '68 Valiant. I will be using four wheel drums with expanders in the front wheel cylinders. The car is to be used mainly for drag racing. I want to eliminate the factory pressure regulating valve and use a Strange proportioning valve in it's place spliced into the rear brake line. This makes it easier to install a line lock. Am I going to have any problems doing this?

Cecil

Cecil,

This is basically what I plan on doing with my valiant (drums). Until I got to the disk conversion.

Do you need expanders in the rear wheel cylinders as well?

I am planning on using a pre 75 MC so that it has the residual pressure valves in the MC. Then I shouldn't need the expander disks.

Do all rebuilt wheel cylinders have expander disks?

John Killin

John, the master cylinder I want to use is the newer aluminum one, not a cast iron unit. It's for my '68, not the '66. Most if not all remanufactored aluminum masters are for front disc and rear drum brakes. These should have a residual valve for the drum rear but not the disc front. So an expander has to be used on the front wheel cylinders to keep the pistons from retracting too far. I don't see why expanders are needed on the rear. I'm told all new remanufactored wheel cylinders and rebuild kits have expanders. I have the rebuild kits ordered, haven't seen them yet so I don't know if expanders will be in them, but I plan on using them only on the front. Even if a aluminum master for drum brakes is available, I want the disc model as I have an old Strange Engineering medium duty disc brake package. It came with JFZ calipers, now out of business, but uses Wilwood pads and the O-ring kits are available. I'm not sure yet if it will go on my 9" spindles, may have to get 10" for it to work, so this is a furture project (I have PLENTY of those).
I just don't see why I have to have the factory pressure regulating valve, it just gives a momentary bias between front and rear when stopping. Keeping it makes it a hassle to install a Line Lock since there are two outlet lines for the front brakes that will have to be merged into one going in the LL, then back to two after the LL. . Again this is for a '68 Valiant that's primary purpose is drag racing. Is it going to be unsafe ditching the factory valve?

Cecil