hey guys , i am running a mopar front brake(volare style)and a ford rear style with a ford master cylinder / booster . will a ford proportioning valve work or should i use the mopar . and will any style from the two work the same (ie granada / crown vic --- volare /fifth ave etc )as long as they are disc front and drum rear? thanks.

 

Either should work but I'd use the Mopar unit since the fitting sizes are sure to match and make plumbing easier...and if you keep it all Mopar it will be easier to remember if and when parts replacement becomes necessary. Try to use the one that came with the MC if you can but as long as it comes from a similar vehicle with disc/drum it should not matter.

 

I'd say either or woudl work just fine. Which one do you ahve laying around? thats the one I would use.

On my truck I'm running a power booster form a mid 90's Ford Focus, a master cylinder from an early 80's Cadillac, front calipers from an early 70's Cadillac, 1960 Ford rear brakes with 69 Ford hardware. The proportioning valve I'm using is from an early 70's midsized Buick. (somewhere I have a list of what parts came from where...I had to write it all down so I'd remember)

Bobby

 

Bobby,

Have you tried a hard stop with your truck yet? I am curious as to how front to rear brake bias is with the fixed combination valve. I was still working with my brakes when I had to quit for the winter but when I was testing them it seemed that the front brakes locked up long before the rears. I am wondering if that is because these trucks have so little weight on the rear and if I might need a different combination valve or if I need to replace it with an adjustable proportioning valve. It seems to me that the front to rear brake bias on a pickup truck with probably 2/3 of the weight in the front is going to be quite different from a passenger car where the weight is closer to 50-50.

Any comments from anyone on this thought is appreciated...

 

Vern,
I found my list, my proportioning valve is from a 1972 Buick Skylark. I have hammered the brakes a time or two, but never enough to lock them up and skid the tires. From a "seat of the pants" assessment it feels pretty equal front to rear.
Overall it feels really good.

The way mine are plumbed is; The line from the large reservoir on the MC goes through my line lock solenoid and into the proportioning valve, a seperate line comes out of the proportioning valve that goes to each front brake caliper. The smaller reservoir on the MC goes to the proportioning valve and out to the rear brakes.

You would think that if anything the rear brakes on a truck would lock up first due to less weight being on the rears. How did you plumb your vavle? is it plumbed liek it was on the donor car?

Bobby

 

Prop valves are supposed to be for the rear brakes.

When you step on the brakes the center of gravity moves forward, lightening the load on the rear tires.. under some pressure condition the rears will lock before the fronts.. causing the rear end to come around if there is any left/right imbalance (I just had this lovely thing hapen in a NEW car)..

Of course the production versions are the non-adjustable final setup after an adjustable one is used on the near production vehiclem with some slop thrown in..

For me its one line out the master for the rear, thru the prop valve to the rear wheels.

I am currently using the add on valve (see my gallery), but will be replacing the master with one from CPP that has the adjustable valve intergrated into the master. (MCPV-1) see http://www.cpptalk.com/Hot.htm

 

Bobby,

Mine is plumbed exactly like it came out of the donor car and as you described yours. All my testing was done on a gravel driveway at less than 10 mph. Perhaps I need to be on asphalt and going faster for any test to prove anything. But so far I haven't gotten the brakes good enough to try that. I'm pretty sure the fronts are supposed to lock up first but in my case it doesn't seem like the rear is doing much anything. I haven't been able to determine if that is due to some problem with the combination valve but according to tests I've done the combination valve is good. So, the idea that the truck having such a weight imbalance seemed like a good place to place the blame.

 

Vern,
I'll do some experimenting this weekend with my truck. I'll find a gravel road and try a few 10 mph stops. I might even try locking them up on hard pavement and see what its like.

I'm with you, if you don't feel confident about the brakes in your driveway then don't take it out on the road. I'll let you know what I find out.

As long as we've highjacked this thread----It looks like you might finally get lucky on a speaker grill. I have my fingers crossed for you.

Bobby

 

Bobby -

With that mish-mosh of brake parts, are you going to name your truck Frankenstein?

...sorry.

 

Randy,
LOL, thats why I had to write it all down, I started losing track of what came from where. Here is a breakdown of the majority of the parts;

1949 Ford F1

CHASSIS:
Frame manufacturer: Ford
Modifications: 1972 Caddy trans x-member, boxed front by me, rear x-members by me
Rearend/Ratio: 1960 9” Ford, 4.10
Rear suspension: stock
Rear brakes: 1960 Ford drum with 1969 self adjusters
Front suspension: stock with several leaves removed by me
Front brakes: ECI disc conversion, 79 F-150 rotors, 72 Caddy calipers
Master cylinder: 1979 Caddy with late 1990’s Ford Focus power booster, Jegs line lock solenoid, 1972 Buick proportioning valve and front rubber brake lines
Brake Pedal assy: Custom hanging pedal assy by me
Steering column: 1972 Caddy tilt & telescoping
Steering: Toyota PS box, GM Saginaw pump, custom made hoses, intermediate steering shaft , “U” joints, drag link, and pitman arm by me
Front wheel make, size: 15” Cragar SS Mags
Front tire make, size: ugh--bias plies
Rear wheel make, size: 15” Cragar SS Mags
Rear tire make, size: ugh--bias plies
Fuel tank: 1985 Chevy Blazer, 31 gallon w/fuel sender and mounting straps, marine flush mount fuel filler neck in right rear fender

ENGINE:
Year and make: 1972 Cadillac
Displacement: 500ci
Camshaft: stock
Compression ratio: 8.5:1
Heads: stock
Horsepower: 365 @ 4400rpm
Torque: 535ft.lbs @ 3000
Manifold/Induction: stock—for now(plans for port injection)
Ignition: 1975 Caddy HEI
Headers/Mufflers: stock exhaust manifolds
Air cleaner: 1953 Caddy dual scoop housing
Radiator: 1976 Dodge ¾ ton truck 4 core, fabricated my own radiator support

TRANSMISSION:
Year and make: 1972 Caddy TH400
Shifter: B&M Megastar truck shifter

BODY:
Body style/Material: Stock F1, steel
Body manufacturer: Ford
Body mods: 1964 Mercury chrome fender spears added to doors, 1963 Ford XL500 emblems from a 1963 Galaxy glove box door added to hood sides, 1946 Chrysler Town and Country tail light housings with blue dots, 2005 GMC bed floor on custom made sub structure
Horns: Early 80’s Cadillac
Bodywork: yes it needs it
Paint: not yet
Paint type: currently faded Meadow Green and primer…ugh

INTERIOR:
Dashboard: stock
Gauges: 1990 GM Van, gauges fitted into my stock gauge housing by me
Wiring: EZ Wiring 21 circuit harness
Steering Wheel: 1972 Caddy
Seats: 1995 GMC Suburban 6 way power w/lumbar--headrests removed
Material/Color: leather, tan
Carpet: non-existant

as quoted from the movie Young Frankenstien "it's alive, IT'S ALIVE!..."

Bobby

 

I rest my case!

 

Bobby,

I'd be interested in what you find...missed the speaker grill again but I'll keep trying. I don't care if you want to outbid me. I'm trying to get it cheap...

 

What I would use is a Wilwood Proportioning Valve that is adjustable. It is put in the rear brake line. The reason you should use one is because the disc brakes in general need 1000-1200 PSI to lock up, while the rear drum brakes are Bendix self energizing and may require as little as 250 psi to lock up. With a truck, and no weight in it the rear brakes should lock up first so that when you have weight in it or are towing, the brakes will be right for that use. If you never tow or haul, then you can adjust the rear brakes for better balance with the front with the truck unloaded......

This is not to suggest that OEM proportioning valves are not usable or that they will not work correctly. It may be that everything works perfectly with a non adjustable proportioning valve, but it is not adjustable........

I never run brake boosters, as I like a high pedal which is easy to modulate. I use separate master cylinders, with pistons sized properly for disc calipers, and for drum brake wheel cylinders....... When setting up a system, correct sizing with no vacuum booster means the brakes always work even if the engine dies while you are going downhill...............

Regards,

Alanco

 

Alanco,

That makes sense. I'm not looking for perfection just decent brakes but I am looking for something better than what I have. I have used adjustable proportioning valves before but only with a single reservoir MC and no combination valve. If I use an adjustable proportioning valve should it be plumbed after the stock combination valve or should the combination valve be elminated? Does it matter either way?

 

You should have a metering valve in addition to the adjustable proportioning valve if you plan to haul or tow anything. The proportioning valve just sets the brake bias. You still need the metering valve to hold off the front discs to engage the rear drums first.

I kept the power booster because I didn't think manual brakes would have enough pressure for 12 9/16" disc with big dual piston calipers and 12x3" rear drums.