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DLF
05-11-2012, 01:19 PM
In the rear brake lines at the rear of the Driver's fenderwell.

What exactly is this thing? Anyone know the part number? Where can I get one?

It's leaking at the rubber o-ring/seal in the middle.

Thanks!

S_Mazza
05-11-2012, 02:13 PM
I don't think I have EVER seen those. Your car is a 1995, though, so it may be different from my 1990.

mkbrower
05-11-2012, 05:09 PM
Sorry. When I replied I was thinking something else
Mark

90sc35thann
05-11-2012, 05:16 PM
I think it is just a union.

mkbrower
05-11-2012, 05:35 PM
I looked it up, its a brake pressure control valve. It controls brake pressure to the rear brakes to try and maintain brake balance front/back. The only number I could find was 2B091.
Mark

RalphP
05-11-2012, 06:35 PM
That would make it the proportioning valve.

RwP

DLF
05-16-2012, 07:26 PM
So I found another pair of "valves", but they're marked RED instead of CLEAR as the original was. Does anyone know what the markings mean?

DLF
05-16-2012, 07:30 PM
That would make it the proportioning valve.

RwP

BTW, I don't know how a "valve" with only two fittings could proportion anything. I can see it restricting flow, or acting as a check valve, but to actually proportion anything, it would require three fittings, with connections to both the front and rear brakes.

fast Ed
05-16-2012, 10:21 PM
Doug, I'm seeing F4SZ 2B091 B in the parts catalogue that I can access, but I'm guessing that it is likely obsolete from Ford. Referred to as a "brake pressure control valve".


cheers
Ed

RalphP
05-16-2012, 11:33 PM
BTW, I don't know how a "valve" with only two fittings could proportion anything. I can see it restricting flow, or acting as a check valve, but to actually proportion anything, it would require three fittings, with connections to both the front and rear brakes.

Then how do the ones on base TBirds work? You know, the one that screws into the master cylinder and then the line to the rear screws into them?

Only takes an input and an output.

Hell, my step-son's Taurus has a load-adjusting prop. valve - it's got two in, two out, and a spring that goes to the rear torsion rod (the one that runs from the bottom of the spindles across). NO connection to the front!

And it does the proportioning by restricting the flow.

RwP

DLF
05-16-2012, 11:47 PM
Doug, I'm seeing F4SZ 2B091 B in the parts catalogue that I can access, but I'm guessing that it is likely obsolete from Ford. Referred to as a "brake pressure control valve".

cheers
Ed

And none showing up on any of the part locator systems that I've tried.

Thanks!

I'd really like to know why the CLEAR version is on my SC and the RED version is on my LSC. If it's due to the larger stock front brakes on the LSC, I wonder if putting the RED version in my SC, since I'm running Cobra sized rotors F&R now, would be better?

ALS35
05-17-2012, 07:49 AM
Guessing from looking at your pictures, The red and clear markings have something to do with the orifice size. Kind of like jetting a carb. Different models, different orifice, same body. Saves manufacturing costs. Did you try to take it apart and change the o-ring?
Alan

DLF
05-17-2012, 11:19 AM
Guessing from looking at your pictures, The red and clear markings have something to do with the orifice size. Kind of like jetting a carb. Different models, different orifice, same body. Saves manufacturing costs. Did you try to take it apart and change the o-ring?
Alan

That's my assumption as well.

All the o-ring does is cover a weep hole, so there's an internal problem of some kind. No, I haven't yet taken it apart.

DLF
05-23-2012, 03:12 PM
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 hard lines with some new stainless steel lines.

fast Ed
05-23-2012, 03:48 PM
Interesting find Doug. I'd be curious to hear your feedback once the Mark VIII valve is swapped on, if there is any noticeable difference in braking performance.


cheers
Ed

mkbrower
05-24-2012, 08:30 AM
DLF, are you fabricating your own SS brake lines? If not, who is doing it for you?
I need new ones for mine.
Thanks
Mark

DLF
05-24-2012, 10:55 AM
DLF, are you fabricating your own SS brake lines? If not, who is doing it for you?
I need new ones for mine.
Thanks
Mark

The two rear hard lines in my '95 SC are the same as the two rear hard lines in my '98 Mark VIII LSC. Along with another car that I'm working on, I ordered and received three sets.

I had a friend in MI drop off a set of stock lines to have them duplicated by Inline Tube (http://www.inlinetube.com/).

The two rear hard lines in stainless steel were $210 + shipping. Call and ask for J.D.

I should mention, that while the lines are stainless steel, the fittings are not. :(

mkbrower
05-24-2012, 02:42 PM
Thanks! I'll give them a call. Exactly what I needed to know
Mark

DLF
07-24-2012, 08:45 PM
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.

boogeyman
07-25-2012, 02:19 PM
those look to be residual pressure valves used to keep a certain amount of pressure on the brakes drum brakes typically use a 3psi valve and disks usually run 5-7 psi sime vehicles use a diffrent valve on left and right wheels to ensure even braking given the diffrent brake line lenghts