What is a good web site for ford brake diagrams and part numbers? I've got 30 ford in front, and 67 in back.
How's that combo workin' out for you? I'm going open drive, so I'll use either an 8" or 9" and the brakes it comes with in the back, and I have 40 ford backing plates for the front (and rear, but I was just gonna sell them off), so I was planning on the same setup. What's your issue? Just curious...
First off, you're gonna need a good proportioning valve (I suggest an adjustable one). Those self energizing brakes from the '67 on the rear are gonna lock up before those dual cylinder non-energizing '40 brakes you have up front even engage enough to help stop the car, otherwise. Dave
If this were my car, I would not use a prop valve because my ride would have big and little tires. The bigs act like flywheels, and with proper adjustment, they should not lock up first. I would plumb it with quality parts and make sure no part of the brake tubing was to high as that causes trouble with air locks. I always like to test a new car for brake lockup on a wet driveway with someone watching which end locks up first.
Are you saying that the rear tire's mass alone (with PROPERLY adjusted brakes, I know thats a biggie) will resist them locking up as opposed to the non-energized, skinny tire'd, front brakes? That is if you run big 'n littles (I was thinkin' 600-16s up front and some sort of wider slick-style tire out back)...
Why don't you want to also put self energizing brakes on the front? Then you will stop good for sure. Lockheed and Bendix 'mix" worries me a bit.
Keeerist !! us old farts have been using early Ford fronts with later Bendix style rears on rods for the last 60 or so years. And NONE of them had prop valves either and no problems with the rears locking to soon. The larger rear tires bite better and seems to solve any balance probs.
Yeah, well I'm one of those "old farts" too, 72 next Nov. and been working on cars and hot rods and race cars a loooong time.For my money, i'd install a prop. valve to begin with so as to be able to get it all just right as far as the brakes go. I don't give a fuck if you adjust those self energizing brakes on the rear as loose as possible and the front '40 brakes as tight as you can without a lockup it still ain't gonna be right. Cause when you apply pressure from the master cylinder to the wheel cylinders, those tight front brakes aren't gonna exert any shoe pressure on the drums till the rears also contact the drum. That's the big advantage that hydraulic brakes have over the mechanical ones, self equalizing. And yes, I have spent hours under old Fords adjusting mechanical brakes, only to have the whole adjustment go South on the first hard stop, Real Pain in the Ass! The only way to balance the braking effort on such a mix of brake types is either varied wheel cylinder sizes, or removing some lining from the shoes on the end that locks up first, or a prop. valve. The first 2 choices are too hit and miss, trial and error with a lot of work to make an adjustment, but you just twist a knob on a prop. valve to make a change. Call it lazy or overkill? I call it taking advantage of modern technology while maintaining a traditional look. Dave
Wouldn't using a MC designed for a disc/drum setup help out the different pressure requirements of the old/new combo? Don't MC's designed for a disc/drum setup apply more volume and pressure to the front disc side? I dunno, that's why I'm asking...
NO , not really . I really wouldn't go with out the valve with mixed brakes systems . If were all Energizing then don't need the valve , but with the different style systems , get the valve for safety .
In a word NO! same line pressure at all points. And unless the MC has a step bore for all intents same volume output both front and rear. Caliper pistons are larger area for more applied pressure and move very little compaired to the pistons in a wheel cylinder.
I totally forgot the think of the actual expansion amount, I was just thinking area.... Makes sense now, thanks.
Bettlejuice: Being that under normal operation there is NO mechanical connection between the 2 pistons in the MC you can have some variation in the amount of fluid delivered. But, if the variation is too much the one piston will make a mechanical connection. Think failure on one half of the system or you have pushed back the caliper pistons to replace the pads. I'm afraid in my previous post I made it sound like no variation at all was possiable when there is a small amount. however the line pressure will still be the same at all points in the system. If you had much variance in delivery volume you would always have a low pedal. Hope this clears up some of your questions.