i plan on running a manual disc drum set up. i have a 72 mustang manual master. the front brakes are volare and the rear are 94 exploder. what do i need to do for pressure valves, proportioning vavles ect?? i would really like to use take off parts or something later model that i can get at the parts store if possible... i did a seach and came up with nothing, i know its out there...so if some one can just point me in the right direction.
Disc brakes take a 2 pound residual valve, drum takes 10 pound residual valve. The best thing to do is buy the aftermarket units as they are small and work just as well as a factory part.
I also use an Adjustable proportioning valve ( Wilwood) to help with brake bias... Jegs has it all for a good price... Spoons
a residual valve keeps pressure between the valve, and wheel cyl eliminating having to pump the pedal
a residual pressure valve keeps the brake fluid from draining back into the master cylinder which is common in cars with low mounted master cylinders.
here is a quick diagram i found, i assume it woud be for a firewall mounted m/c because there are no RPV's but it does show a proportional valve. the RPV for the rear would be mounted after the brake light switch!....dont ask how i know this! kropduster, i got my valves and fittings from speedwaymotors.com check 'em out
since this is the case, should mount my pressure activated brake light switch in between the wheels and the rpv instead of the master cyl and the rvp. thought this might cause the lights to stay on? thanks guys for all the responses. this truck wouldnt stand a chance if i had to do it on my own. without the HAMB and all you guys there is no way i could have got this far. thanks again krop-
I'm trying to design a similar system(disc front,drum rear,non-power assist) for my '40 Fd cpe. I found some helpful info at: www.piratejack.net
hey kropduster, if your running tall tires in back and littles in the front you just might be able to get away with out a adj. prop valve because of the bias caused by the size difference. you will also need a metering valve in the front system to hold off the front discs until the brake pressure can over come the force of the rear brake springs.for the master, youll probably want to use a master with a bore between 7/8 and 1 inch.78 fairmonts used a 7/8 bore and 72 stangs used 1 inch masters. be aware of what side the lines exit the master as they could end up smack dab right up against the frame rail.(cant tell you how i know that!) if you find that you do need a prop valve, get a combonation valve off posibly an s-10 truck, that will give you metering and proportioning all in one along with a idiot light. im in the process of setting up the brakes on a 36 chevy p-up and after much digging, this is what ive come up with. oh hey dont forget the residual valves if your master is under the floor. if any of you guys think my thoughts are off the mark , let me know . i set my other car ( 36 ford sedan) up with the combo valve set up and it work real good. mike.
If you want to do it super low budget, you can go to a wrecking yard and get a combination proportioning valve setup out of a similarly sized disc/drum car. I found a nice one in a mid-seventies disc/drum Cougar that looks the same as the aftermarket ones the custom brake places sell. It's brass and about 4" long. It has two leads in, two leads out, and it has a switch that you can hook up to a dummy lite. The switch turns on if you should happen to lose either the front or back brake circuits. If you get a junkyard one, chop off the brake lines so you can get all the flare nuts. Some of the car companies use odd sized larger flare nuts for some of the lines, probably to make it more foolproof on the assembly line. Some master cylinders use odd size flare nuts too (with normal sized brake lines). If you use a good quality flare wrench, the nuts usually break free without getting destroyed.
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