Brake Master Cylinder

[pspeaks]

OK, I didn't take adequate pictures, I'm old, and I can't remember, but.......I'm using a stock 72 master cylinder and can't remember which port goes to the front and which goes to the rear.  Also I'm thinking of using Wilwood proportioning valves (not residual pressure valves).  I use one for the rear on my T-Bucket and it balances the car pretty well, OK, as well as a bucket can be balanced anyway.  Has anyone done this, and would one for the front and one for the rear be a dumb idea, probably so I guess?

[mgb260]

Proportioning valve on rear only. Most masters, front port to rear,rear port to front.Or if two reservoirs, larger one is for front. Don't have an MGB one to look at, as I use separate masters with balance bar.

[DiDueColpi]

Hey Paul,

Jim is right on the money but with one caveat. The B master cyl sits in the car backwards to most. This means that "as it sits mounted in the car" the front port will go to the front brakes and the rear port goes to the rear.
RP valves are strongly recommended to avoid the sinking pedal issues.

Cheers
Fred

[pspeaks]

I used a proportioning valve, and RP valves on my T-Bucket, mostly because the rear wheel cylinders are above the master cylinder, but was not pleased with the look of drum brakes on the rear.  On a bucket everything is visable from the back.  I replaced them with a set of Wilwood Dragster drilled rotors and 4 puck calipers and removed the RP valves but haven't noticed any brake pedal issues.  I did keep both front and rear valves so I'll be prepaired when I start plumbing it.  I hate the idea of plumbing one more set of brakes but I guess we all have to do it.

[DiDueColpi]

Them's the brakes.

I've always used RP valves on every brake system, regardless of the master cyl position. (2psi for discs and 10psi for drums.)
It guarantees a nice high pedal and no air ingress.
If you are doing a disc front and drum rear setup you might want to include a "hold off" valve as well. These slow the actuation of the front discs slightly and allow the rears to actuate first. This makes the vehicle far more stable when braking.
North American cars generally use a combination valve that has all of the above features in one handy unit. It also has a brake failure switch built in so you could replace your old "H" valve with this one piece. Just pick one from a vehicle that has similar brake components to your setup and you're golden.

Hope thats helpfull.
Cheers
Fred