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Topic: Leaking proportioning valve? (Read 2812 times) previous topic - next topic

Leaking proportioning valve?

Looks like the front of the valve is leaking...is that nut supposed to adjust it, just out of curiosity? I cant find em on Advance Auto's site...do I need to hit a yard? What else interchanges...just any non-ABS fox vehicle, or is it a little more specific?
1987 20th Anniversary Cougar, 302 "5.0" GT-40 heads (F3ZE '93 Cobra) and TMoss Ported H.O. intake, H.O. camshaft
2.5" Duals, no cats, Flowmaster 40s, Richmond 3.73s w/ Trac-Lok, maxed out Baumann shift kit, 3000 RPM Dirty Dog non-lock TC
Aside from the Mustang crinkle headers, still looks like it's only 150 HP...
1988 Black XR7 Trick Flow top end, Tremec 3550
1988 Black XR7 Procharger P600B intercooled, Edelbrock Performer non-RPM heads, GT40 intake AOD, 13 PSI @5000 RPM. 93 octane

Leaking proportioning valve?

Reply #1 –
Leaking? Really? Hmm I don't think that nut on the front is for adjusting it. IIRC removing that nut allows you to gut it and then use an adjustable proportioning valve. I think that a stock replacement one is going to involve going to a junk yard.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Leaking proportioning valve?

Reply #2 –
Do you mean the front that has no lines going to it? The actual valving is inside there but I don't think I've ever heard of it leak. I agree that a replacement is likely junk yard only but more than that, I don't even see how it would be leaking without physical damage to it. The fluid goes in the top and out the bottom with an orifice within the "valve"/block to regulate how much fluid gets sent down to the bottom. I don't have the pictures readily available but they are out there and show the inner workings.

It can probably just be resealed but since air can get into the lines now, it's probably a good idea to bleed the entire system or air
1988 Thunderbird Sport

Leaking proportioning valve?

Reply #3 –
Yeah the big nut on the front...one day I checked the fluid because I dont very often but say once a month or so it will occur to me and it was VERY low. I filled it up and noticed the next day some drops on the street, and as far as I can tell its coming out that front end. Ill clean everything and make sure but it sure looked like it originated right from that piece.
 
My lines are all fine, no rust, nor are any bent for whatever reason or broken, as I said Ill check into this but if I have to replace it what else has the same valve, few yards around here have thundercats.
1987 20th Anniversary Cougar, 302 "5.0" GT-40 heads (F3ZE '93 Cobra) and TMoss Ported H.O. intake, H.O. camshaft
2.5" Duals, no cats, Flowmaster 40s, Richmond 3.73s w/ Trac-Lok, maxed out Baumann shift kit, 3000 RPM Dirty Dog non-lock TC
Aside from the Mustang crinkle headers, still looks like it's only 150 HP...
1988 Black XR7 Trick Flow top end, Tremec 3550
1988 Black XR7 Procharger P600B intercooled, Edelbrock Performer non-RPM heads, GT40 intake AOD, 13 PSI @5000 RPM. 93 octane

Leaking proportioning valve?

Reply #4 –
If it is the valve let me know. I usually go to the yards around here every 2 weeks or so in the summer so if I find one I'll let ya have it for what ever it costs.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Leaking proportioning valve?

Reply #5 –
Okay, here's information. As you can see below, there is a simple oring used to seal the front thread. You will need to replace it and bleed the brakes.

The stock block:


The internals removed:


The internal workings:
1988 Thunderbird Sport

Leaking proportioning valve?

Reply #6 –
I had one leak before in my '87 Sport, and it was different than the one Seek posted. Mine had a rubber bit in the center of that big bolt, and it was leaking at that rubber bit. I just replaced the bolt with one out of a junkyard proportioning valve (it was much easier than trying to free up all the brake lines/fittings)
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Leaking proportioning valve?

Reply #7 –
YES Ive got some black thing in the center...it must be that. Thunderjet, theres one place Im gonna try but if it turns up nuthin Ill let ya know so you can go grab me a new....bolt :hick: haha
1987 20th Anniversary Cougar, 302 "5.0" GT-40 heads (F3ZE '93 Cobra) and TMoss Ported H.O. intake, H.O. camshaft
2.5" Duals, no cats, Flowmaster 40s, Richmond 3.73s w/ Trac-Lok, maxed out Baumann shift kit, 3000 RPM Dirty Dog non-lock TC
Aside from the Mustang crinkle headers, still looks like it's only 150 HP...
1988 Black XR7 Trick Flow top end, Tremec 3550
1988 Black XR7 Procharger P600B intercooled, Edelbrock Performer non-RPM heads, GT40 intake AOD, 13 PSI @5000 RPM. 93 octane

Leaking proportioning valve?

Reply #8 –
Ok. I know the yard by me has an 80 or 81 Fairmont Futura Coupe and a couple of 87-88 5.0 Mustangs so I bet I can find the thing :hick:
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Leaking proportioning valve?

Reply #9 –
Oh wait which bolt? :hick:
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Leaking proportioning valve?

Reply #10 –
Haha it's that very first picture that Seek posted...that big guy on the very front of the block.
1987 20th Anniversary Cougar, 302 "5.0" GT-40 heads (F3ZE '93 Cobra) and TMoss Ported H.O. intake, H.O. camshaft
2.5" Duals, no cats, Flowmaster 40s, Richmond 3.73s w/ Trac-Lok, maxed out Baumann shift kit, 3000 RPM Dirty Dog non-lock TC
Aside from the Mustang crinkle headers, still looks like it's only 150 HP...
1988 Black XR7 Trick Flow top end, Tremec 3550
1988 Black XR7 Procharger P600B intercooled, Edelbrock Performer non-RPM heads, GT40 intake AOD, 13 PSI @5000 RPM. 93 octane

Leaking proportioning valve?

Reply #11 –
Ok I'll see if I can pocket one from a 5.0 Mustang at the yard ;)
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.
 

Leaking proportioning valve?

Reply #13 –
I had the one in my 78 Grand Prix spring a leak and have an internal issue resulting in no brakes.
85 Tbird 5.0
78 F150 351w
13 F150 4x4 3.5 Ecoboost