Brake Valve/Junction?
- Thread starter DLF
- Start date
DLF
New member
I've been able to determine that these are restrictors used to balance front and rear braking, i.e. a poor man's proportion valve setup. Ford calls it a brake pressure control valve, p/n F4LY2B091AC.
I still don't know what the CLEAR and RED markings mean, but I would guess that it has something to do with the amount of the restriction.
I still don't know what the CLEAR and RED markings mean, but I would guess that it has something to do with the amount of the restriction.
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psychostang
Moderator
I think your right Doug. Clear and Red are designed to help the assembly line person put the right valve in the right place.
That is what they are for. When NJ did the safety inspections when I first got my Mark VIII, they failed me for brake balance. I took it to the dealer under warranty; they said the brakes were fine; the fronts were stopping the car before the rears had to do much. They said they did not want to mess with that valve, required special tool and diagnostics.
DLF
New member
I got my hands on a pair that's marked CLEAR, and they have visibly smaller orifices.
Hard to tell from the pictures, and I don't own a numbered drill set, which would be the best way to measure them.
The CLEAR pair is stock on my SC, and the RED pair is what comes on Mark VIII's.
I going to guess that more rear brake is needed with the larger stock Mark VIII front rotors, and since I have Brembo's and Cobra rotors, I'll be installing the RED pair in my SC when I swap out the rear lines.
Hard to tell from the pictures, and I don't own a numbered drill set, which would be the best way to measure them.
The CLEAR pair is stock on my SC, and the RED pair is what comes on Mark VIII's.
I going to guess that more rear brake is needed with the larger stock Mark VIII front rotors, and since I have Brembo's and Cobra rotors, I'll be installing the RED pair in my SC when I swap out the rear lines.
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It looks like there is a removable orifice plate in there. The red might refer to that red orifice. Obviously we don't know for sure but I would not be suprised if you can take it apart and turn a Red into a clear by swapping orifice. Of course there could be other internal parts that are different. When I worked in manufacturing hydraulic valves for heavy machinery we made assorted valve models by changing just an orifice piece.
DLF
New member
Worked on swapping this unit out on my SC today and learned a bit more about it. Seems that the two "valves" with the restrictors in them can be separated and swapped into the upper part. This meant that the leaky valve I had could be replaced while still using the original upper section. Of course, I replaced both valves in order to maintain equal rear brake pressure.
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Greetings all. I know this is an old thread, and there are several other similar discussions in the forums. Like this one, all of the threads are several years old. I have this issue/problem. The one marked "red" on our 24hoursoflemons 1994 Mark VIII is plugged/clogged/broken. This one feeds the driver's rear wheel. We have good brake pressure at the other three wheels. However, no fluid is passing through this valve. There is pressure at the line as it enters the valve, but nothing passes through. We tried blasting it with brake cleaner, with PB blaster, and compressed air. All of these things will flow in reverse (from the output side of the valve to the input side, but not in the correct direction). As everyone knows, these parts don't seem to be in stock anywhere. Has anyone had success perhaps finding an alternative part number from another Ford product that works as a direct replacement. We are hoping that there is a similar valve which has the same thread pattern where it screws into the brass housing perhaps? We haven't tried calling the local yards to see if anyone has a Mark sitting around yet - that might be our next option. Any help on where we can acquire a replacement would be appreciated. The brass housing is in good shape and the valve feeding the passenger rear is working as it should - it's just the passenger side that's bad. I suppose an additional option would be to just bypass it and put in an adjustable proportioning valve instead.
driller
El Presidente
What's odd is I know my '93 did not have any such valve(s) when I replaced the brake lines. So, I would entertain eliminating it.
If you then find the braking characteristics undesirable, you should be able to put in an adjustable proportioning valve.
http://stoptech.com/technical-support/technical-white-papers/proportioning-valves
If you then find the braking characteristics undesirable, you should be able to put in an adjustable proportioning valve.
http://stoptech.com/technical-support/technical-white-papers/proportioning-valves
Thanks! We found one at a pick n pull from a 95 and it works great! Installed it tonight.
Now, just to figure out why the pedal is a little spongy....... Prob need to bleed them again after a little drive time.
driller
El Presidente
tonybrooklyn
New member
I think you hit the nail on the head as far as an adjustable valve.
Just make sure it is set up for front and rear.
You would have to totally by pass the old system.
You might wanna try contacting. Race Bronco2 his name is Carlos.
Nice man very helpful always has parts for Marks.
If you cant get in touch with him here.
He is on Ebay as well.
Good Luck