I just installed a '67 Mustang master cylinder on my '54 Chevy....I welded up a bracket to mount it under the floor as well as hold the pedal swivel. After wallowing in my pride of a job well done, it dawned on me that I have no clue as to which brake line goes where, which port on the master is front or rear, should I get a Mustang proportioning valve, am I missing anything? Im sure the answers are simple, but this is the first time I have upgraded brakes where the parts are not a direct bolt on.
which `67 mustang master cylinder are you using? drum/drum or disk/drum? what are you using for brakes front and rear?
Damn, I knew I left something out....its a drum/drum master with stock '54 drums on fromt and mid 70's gm drums on rear.
the small reservoir of the two is for the rear brakes.it usually has the largest bore outlet -but not always. If you are using 4 wheel drums I would not use a proportioning valve. I personally think they are not needed in a lot of cases.
actually the drum/drum master cylinder has two chambers of the same size, i usually run the front one to the front brakes and the rear one to the rear brakes. i agreee,you probabilly don't need a proportioning valve....but i would put two 10# residual check valves inline the front port will have an inverted flair with 1/2"-20 threads inside.....i use edelmann fitting # 258350 to get down to the 3/8-24 on the 3/16 inverted flair on 3/16" brake line the rear port will be 9/16-18 thread...i use edelmann # 258302 to get down to 3/16" brake line
Yep...the Mustang drum/drum master should have two chambers the same size...won't matter which axle you plum to which chamber, but going front to front and rear to rear makes it easy to remember. You don't need a proportioning valve because your wheel cylinders are different sizes front and rear (bore size) to make up for it. Residual valving may be built into the master cylinder already...if not, adding a couple of aftermarket ones is no big deal while your plumbing the system.
[ QUOTE ] Residual valving may be built into the master cylinder already...if not, adding a couple of aftermarket ones is no big deal while your plumbing the system. [/ QUOTE ] Is there an easy way to tell if it is built in?
Not sure on that...but I was told years ago that most 60s/70s era drum/drum masters had the valving built into them. Check with the supplier that remanufactured your master cylinder, they should know for sure.
I actually researched this for a story--which reservoir runs front/rear. What a clusterfuck. The vintage manuals I consulted didn't agree. The vintage gearheads I consulted didn't agree. The reproduction companies didn't agree. Master Power Brakes et al didn't agree! Even the factory applications don't agree--some GMs are front res feeds the rear, some are front feeds the front. With yours, consult a Ford reference and see which reservoir feeds front or rear ON THAT APPLICATION ('67 Mustang). I'd agree about leaving out the prop valve on a drum/drum system. And don't waste your money on one of those adjustable pieces of junk. I don't know one way or the other about the 10-pound residual valve: seems like a well-adjusted pedal and shoes would make it unnecessary, but that's just my opinion. -Brad
Dissasemble the piston and cups from your master clinder.(remove the snap ring at the back of the bore). First out of the hole will be the piston followed by the cup (rubber). Next up is the spring and attached to the front of the spring is a disclike valve with holes around the circumfrence. This is the residual pressure valve. If you are going to use an external one remove the one from the master cylinder and reassemble the parts. If you use and external one and leave the cylinder one in place the brakes won't release. Hope this helps. Frank
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