Help Needed - Proportioning Valve For Disc/drum Swap

65-Fstbk · Sep 13, 2012

Can someone clarify something for me? I am doing the Granada swap on my 65 right now and have the proportioning valve from the donor car (see pic).

Q - Do I also need a secondary adjustable valve that goes to the rear brakes or is this the only valve I need?

Q - 65 Mustangs didn't have a brake warning lamp (I don't recall) so what do I do with the electrical connector located on the top of this proportioning valve?

bacfire · Sep 13, 2012

Q1 - As long as it's working properly, the stock valve is all you need.
Q2 - Nothing. And no, AFAIK no '65 had a warning lamp.

horse sence · Sep 13, 2012

you can wire the warning light switch in to a small light added to your dash.
it simply breaks connection in a positive lead ,and connects when the proportioning valve is tripped.

65-Fstbk · Sep 13, 2012

Thanks to both Bacfire and horse sense for helping out. I will make sure the old unit is in good order and go with that. As far as the electrical switch goes, is there a wiring diagram for that? One side goes straight to ground right? How does the other side work? (wiring is not my strength).

horse sence · Sep 13, 2012

the switch just splits a power wire and goes to one side of the light . the other side of the light is a ground

65-Fstbk · Sep 14, 2012

Thanks again horse sense. I don't have the other half of the connector so I will need to get. Looking closer at the half that screws the Proportioning Valve (PV) body it seems power is supplied through a center connector.

One more thing. I was looking for a rebuild kit for my PV and did find one for $25 but it's missing something that seems to be unique to the unit I have. As I understand it the steel plug on the end of these PV's is usually solid. The steel plug on the end of mine has a rubber bulb gasket sticking out of the middle (see picture). This gasket is not included in the rebuild kit and t he folks selling the PV rebuild kit aren't certain what the design change was meant to do. Do you know anything about this?

Wondering if I can just swap in a typical "solid" steel plug.

horse sence · Sep 14, 2012

not a clue .what did it come out of? looks like you could plug it.

bartl · Sep 17, 2012

If it isn't leaking I'd leave it alone. The rubber plug probably allows for some expansion when the PV moves. You can wire the brake warning lamp as follows.... hot lead from an ignition-on source or directly from the "C" terminal on the ignition switch (I'd also run this wire through a low-amperage inline fuse, maybe 3A) to the connector, other wire on the connector back to a warning lamp and then from the lamp to ground. As far as an adjustable PV you can add that to the rear line if you need to or change springs in the internal PV.....IIRC, heavier spring = less pressure to rear brakes.

horse sence · Sep 17, 2012

i agree with the rubber plug.there has to be some place for pressure on the back side of the valve to go/the rubber plug.the valve is o ringed so fluid will not leak .i would atleast plug it with silicone,just to keep dirt out. but dont get it up inside, it may stop the valve form being able to move.

65-Fstbk · Oct 3, 2012

Thanks guys.

Tim65GT · Oct 15, 2012

the pic you posted looks like a combination valve (Metering, Proportioning Valve and Differential Switch)
The electrical conection has already been explained, but it's hardly worth the effort to use it. It's purpose is to let you know the pressure in the front or rear brake system has dropped (usually from a failed brake hose or a bad wheel cylinder). A pintle inside will shift from one end to the other blocking fluid from going out the end with no pressure, so you will still have brakes on the good end (front or rear)

Either way, you will know this when you push the brake pedal down to stop and it sinks to the floor. Once you recover from the "OH S**T!" moment and pump up the pedal that's when you notice that "Oh yeah, the light works, I must have a brake system issue" lol.

The rubber cap on the end is a dust shield that keeps crap out of the end where a pintle is pushed in order to bleed the brakes. You can manually push it back in, or once you fix the leak, you can open a bleed port on the good circuit to have system pressure push it back to the center position.

I actually had this happen to me when I took my dad's '68 International pickup down a logging trail and ripped a brake hose. Didn't realize it 'til I was back on pavement heading down a hill!

65-Fstbk · Oct 15, 2012

Thanks again.

I have ordered my rebuild kit for the block and am just waiting for it to arrive. I don't think I will even hook up the brake warning light b/c the car never had one to begin with. I am thinking of swapping in a solid cap in lieu of the one with the rubber gasket in it though. My rebuild kit doesn't include that rubber "bulb" gasket for the cap and I don't want any leaks.

65-Fstbk · Oct 31, 2012

Ok I have rebuilt the distribution block and mounted it where the old T-junction was from the single bowl master. New master is also on and brakes lines are plumbed between them. I flared the lines myself and seem to have 1 slow dripper so I'm hoping that a reposition and tighten will cure that. Thought I would post a pic of my set-up and brake line bending to see what you think. I'm a first timer for brake lines so go easy on me.... . I think it looks ok.

horse sence · Oct 31, 2012

looks clean to me . nice job

Help Needed - Proportioning Valve For Disc/drum Swap

65-Fstbk

bacfire

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horse sence

65-Fstbk

horse sence

65-Fstbk

horse sence

bartl

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horse sence

65-Fstbk

Tim65GT

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horse sence

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