NE 1 have a factory shop manuals? I'm looking for PV Valve specs...

[qikgts]

I'm trying to compile/compare a list of "all" (Fox and SN) Mustang Proportioning Valve specs and they should be in the factory manuals. If anyone who has factory service manuals would like to help, I'd certainly appreciate if you could post up what the manuals state... I'm looking for the split and slope specs...

Here's what I have already. I've noted the sources of only a few specific valves because those are the only Ford published ones I could find. The others are what random folks on the net have provided not stating the source...

'84 to '86 SVO- 200 psi split / .28 slope (Ford Service Manual)

'87 to '93 Fox (Unknown Engine)- 300 psi split / .28 slope

'93 Cobra R- 250 psi split / .36 slope

'95 Mustang Cobra R- 400 psi split / .43 slope

'94-'95 Cobras- 250 psi split / .36 slope

'94-98 V6 and GT- 400 psi split / .42 slope

'96-98 Cobra- 350 psi split / .36 slope

'99-'04 Mustang (Unknown Engine)- 700 psi split / .43 slope



(Mods, please feel free to relocate the thread if need be...)

[kj_80Cobra]

From my Factory service manuals:

1980 Mustang/Capri 2.3L 400 / .28
1980 Mustang/Capri, Fairmont/Zephyr 3.3L, 4.2L, 2.3L Turbo 300 / .28
1987 Mustang - All engines 300 / .28

[qikgts]

Thanks kj 80Cobra... Great info!!!

Anyone else?

[qikgts]

ttt...

[qikgts]

It's been a few years so upsydaisy... lol

[qikgts]

Might as well push it up...

[gmatt]

from the 1981 specifications booklet:
T-bird, XR-7 3 way alum. 400psi/.43 slope
F/Z (sedan) 2 way alum. 300psi/.43 slope
F/Z (sta. wagon) 2 way alum. 400psi/.43 slope
Mustang/capri 2.3L 2 way alum. 400psi/.28 slope
Mustang/Capri 2 way alum. 300psi/.28 slope
Granada/Cougar 2 way alum. 300psi/.43 slope

[qikgts]

The more the merrier!

Thanks!

[OldFox]

* Disclaimer to anyone who reads this : Any information I provided below is sharing my research, not advise on what to do with your car, so please do your own research when modifying your brake system.

While there are several different discussions on these valves, I picked this one because my purpose is more focus on comparing the valves as qikgts did. I've recently run into the dreaded proportioning/distribution combination valve saga. The reality is these units are 40-years-old and majority of brake systems did not get the fluid changed regularly, which resulted in stuck corroded valves.

I'm also fully aware of the rebuild kits and instructions offered my Muscle Car Research here (I bought one)...
https://www.musclecarresearch.com/va...-E0ZC-2B328-AA
https://www.musclecarresearch.com/E0ZC-2B328-AA-rebuild
...and the problem one person had with it, but the problem isn't with the kit, its with corroded 40-year-old parts.

Long story short, when I went to change brake fluid the flow was weak to several wheels, that's when I pulled the combo valve apart and found corrosion like many others. Mine is actually in surprisingly good shape due to low miles, no winters, and fluid being changed several times in lifetime. However, the age still caught up to it and it has pitting in critical sealing areas (inside bore and end fitting) so it can't be saved/rebuilt (see photos below).

That's what led me to this posting by qikgts and I wanted to add to this long-term discussion with what I found...

At first I thought I could just by a V8 core and swap the good parts and use rebuild kit, great in theory but the cores I bought were worse than mine in most areas. Then I bought 2 SVO cores thinking most of the individual parts were the same (yes they are) and then I came across qikgts post that said...

I wouldn't use that SVO piece on a disc and drum set up. SVO has discs front and rear and the bias front to rear is much different than any other Fox. Way more in the rear.

'84 to '86 SVO- 200 psi split / .28 slope

...and from above...

V8 Mustang/Capri 2 way alum. 300 psi / .28 slope

...and that is what peaked my interest to compare the two (V8 vs SVO) to see what was different side by side. Before I took them apart my "assumption" was they would be mostly the same with the "lower level" proportioning valve being different due to disc vs drum. After disassembly my assumptions were correct, the majority of parts appear identical. The only difference I could find is the spring on the proportioning valve in lower level, and fitting size on the one top port, that's it. Its my guess that the Ford engineers repurposed the V8 assembly, changed the spring for the rear, and changed the one fitting thread size so people couldn't/wouldn't directly swap the part. Everything else looks the same.

So my question for qikgts is, where do you think the 300 vs 200 bias is at on the SVO combination/distribution/proportioning unit? Because I'm not seeing it anywhere except for the spring at lower level proportioning valve which can be changed, and my understanding is that is to prevent rear wheel lockup under hard braking. Are the V8 and SVO master cylinders different and that's where its at?

Why am I asking? Because I've been trying to fix this car for 2 weeks using used parts with no success, all the cores I've bought are junk, summer is here and I can't drive the car, I refuse to put an aftermarket setup on firewall (mostly original car), and I have a brand new SVO assembly in the box begging to be used. If I can use the V8/rear-drum spring and one fitting adapter on the new SVO unit, its should be the same as V8 when new. What am I missing?

Thanks for any help.

[OldFox]

More...

[OldFox]

Update 1: After looking at it closer I might be able to salvage my original block after all with the rebuild kit and a good end fitting from one of the cores, because in the bore where it "steps down" and becomes narrower just before the brake light switch cavern, I previously thought the o-ring sealed there and I wasn't comfortable with the minor pitting there, but I had it backwards because that is just a "stopper" for the brass bushing...

[massacre]

Great thread and pics! Thanks

[OldFox]

UPDATE 2: I'm going to throw one more wrench into the mix.

I just bought an NOS unit that is listed for two separate applications...

1983 - 1993 Ford Mustang brake proportioning valve for 2.3L non-turbocharged disc-drum system
1982 - 1989 FORD MUSTANG
The part # listed for that is E2ZZ-2B257-A and engineering # E1ZC-2B238-AA

When I search that part # I get two results from Ford dealers that associate the part # with a 1985 Mustang...
https://parts.lakelandford.com/p/For...Z-2B257-A.html
https://www.oemfordpartsdirect.com/v...brakes--valves

And its mentioned as being part of the Ford M2300K Kit a quarter century ago...
https://www.corral.net/threads/m2300...st#post-703568

I'm 99% certain its nearly identical to my 1985 V8 block (part # E0ZZ-2B257-A and engineering # E0ZC-2B328-AA).

In summary, any thoughts from seasoned veterans who are more knowledgeable than I am would be appreciated as I'm going to put this relic back together in the next few days. Is there anything else different in the 4cylinder disc/drum unit that I should be aware of? (aside from brake light switch and rear proportioning end cap/spring)

Thanks

[qikgts]

I get satisfaction from learning about how and why things do what they do too so I'm glad this thread was helpful to inspire/assist with a deeper dive.

I too found that specific E2ZZ-2B257-A auction in the last week or so. Glad someone who needs it bought it. If you've got that NOS piece now, just bolt it up and get back to driving. Unless of course you want to start a refurb service or have someone manufacture replacements. That's a half joking comment as you've found out there isn't exactly much of a selection in the market place to replace a unit that's beyond repair without waiting for an overly expensive NOS piece to be for sale...

I believe the orifice sizes and the spring specs are what dictates the split and slope. I didn't see where you showed any actual measurements taken from inside the blocks/orifices and I have never pulled any cores apart from different applications and measured/compared them. There is an obvious difference in the springs though and I appreciate that you showed it. Do you have a good drill bit selection or a set of pin gauges and if so would you be willing to compare and post up if the SVO block and your OE one are machined differently?

[OldFox]

Thanks for the reply. I looked online at brake parts to compare the 1985 5.0 vs 1985 NA 2.3 and all the parts are the same (pads/shoes/rotors/drums/etc) but the calipers are different. Do you know why the NA 2.3 calipers are different than V8 on a 4-eye? I'm assuming it has nothing to do with hydraulics and more about the shape/design in how they bolt to the spindle due the regular suspension vs V8 handling package suspension? The other concern was specs at top of the page where some of the early to mid 80's Mustangs are 300 psi and others are 400 psi (but all with .28 slope).

I didn't take measurements of the orifices, but I'm willing to ship the 83 GT and 84 SVO junk cores to you or anyone else that has the motivation to cut open to investigate further, because to be honest I'm burned out on proportioning valves after this experience and don't want to look at another one after I get my car working again, haha.

There are rumors that a new reproduction combination / proportioning valve is in the works for 4-eyes, but I'm not sure I would trust a recently designed "Made in China" brake unit with no real-world testing (i.e. see the bad reviews for the Scott Drake ones for older Mustangs) so lets hope its a quality made unit.

[1984GTTurboVert]

I replaced the original one on my gt turbo with E3SZ-2B257-B and it was identical from what i remember. Thats for v6 tbirds iirc.
I dont have any pics of the replacement one since its in and i aint going thru that again but i can grab the original one and snap some of it if you want.

[qikgts]

Do you know why the NA 2.3 calipers are different than V8 on a 4-eye? I'm assuming it has nothing to do with hydraulics and more about the shape/design in how they bolt to the spindle due the regular suspension vs V8 handling package suspension?

I think the fluid line is different and the caliper isn't physically the same. The rotors and spindles are the same though.

The other concern was specs at top of the page where some of the early to mid 80's Mustangs are 300 psi and others are 400 psi (but all with .28 slope).

It likely has something to do with the weight of the vehicles and the friction materials. Could also see variations due to rear drum sizes.

I didn't take measurements of the orifices, but I'm willing to ship the 83 GT and 84 SVO junk cores to you or anyone else that has the motivation to cut open to investigate further, because to be honest I'm burned out on proportioning valves after this experience and don't want to look at another one after I get my car working again, haha.

Shoot me another PM and I'll reply with my contact info. I can't say when I'd get to doing it but I'd like to try one day.

There are rumors that a new reproduction combination / proportioning valve is in the works for 4-eyes, but I'm not sure I would trust a recently designed "Made in China" brake unit with no real-world testing (i.e. see the bad reviews for the Scott Drake ones for older Mustangs) so lets hope its a quality made unit.

I couldn't agree more.

[OldFox]

I replaced the original one on my gt turbo with E3SZ-2B257-B and it was identical from what i remember. Thats for v6 tbirds iirc.I dont have any pics of the replacement one since its in and i aint going thru that again but i can grab the original one and snap some of it if you want.

Thanks for offer but I'm going with one of the new Mustang units.

I think the fluid line is different and the caliper isn't physically the same. The rotors and spindles are the same though.

It likely has something to do with the weight of the vehicles and the friction materials. Could also see variations due to rear drum sizes.

Shoot me another PM and I'll reply with my contact info. I can't say when I'd get to doing it but I'd like to try one day.

I couldn't agree more.

Sounds good, thanks again for the help.

PS: Since I won't be using the New Old Stock SVO proportioning valve, its up for grabs if anyone wants it. I paid $400 so I would sell it for $380 shipped and take a small loss on it. If anyone is interested they can send me a message, thanks.

[OldFox]

UPDATE 3: The new fox NA 2.3L 4cyl disc/drum prop valve arrived today (part # E2ZZ-2B257-A and engineering # E1ZC-2B238-AA) and when I went to install I ran into a snag. On the top front where the line from the master cylinder (rear brakes) goes into the valve is the larger size, and I assume the Ford engineers did that so it wouldn't be interchangeable/direct bolt-on.

I had to get a master cylinder adapter (see photos), is that ok to do that? They sell kits at Jegs/Summit with multiple adapter sizes for those purposes. Its all ready to go with new fluid and I plan on test driving it tomorrow......unless anyone has any last minute input, thanks.

[KevinVarnes]

I think I had to use an adapter or two when I put Cobra brakes on my wagon. I don't have any problem with them. It is one more potential failure/leak point, but I think the risk is fairly low in your case. I would be okay running it like that.

[85GTGuy]

Yea, I don't think there's any issue using an adapter like that. As long as it seals up good, everything should be fine.

[OldFox]

Thanks, just got back from test drive. First I took it really easy around neighborhood driving like a 90-year-old man, slowly increasing the hardness of stops, then a few rapid stops from 30mph, and everything seems good. One thing I noticed is when I test drove it before I flushed the brake fluid and discovered proportioning valve problem, the rear wheels would start to lock up on my rapid stop from 30mph, whereas now on the identical road the rear wheels didn't try to lock up, so that's a good sign things are working normal. (I can hear rear shoes moving so rears are working)

The purpose of sharing all this was not only to help myself, but the many others who will walk through the door with the same problem in the future, especially with 40-year-old valves. I just hope the FEP message board and all its knowledge survives.

[85GTGuy]

Thanks, just got back from test drive. First I took it really easy around neighborhood driving like a 90-year-old man, slowly increasing the hardness of stops, then a few rapid stops from 30mph, and everything seems good. One thing I noticed is when I test drove it before I flushed the brake fluid and discovered proportioning valve problem, the rear wheels would start to lock up on my rapid stop from 30mph, whereas now on the identical road the rear wheels didn't try to lock up, so that's a good sign things are working normal. (I can hear rear shoes moving so rears are working)

Congrats! That's great to hear.

I just hope the FEP message board and all its knowledge survives.

That exact thing has many of us here worried.