I'm copying this post from the 80-86 Bullnose forum to see if I can get any traction over here. I also have it posted in the brakes forum.

Let me know if I should gut the "Proportioning pressure regulating control valve"

Join Date: May 2009
Posts: 41
Tarheel Blue
'87 Master Cylinder
Quote:
Originally Posted by LARIAT 85 View Post
I have a 1985 Ford F-150 with a stock cast-iron master cylinder. I was wondering if I could replace the master cylinder with the see-through plastic master cylinder that started in 1987? Can I just replace the cylinder, or will I need to use a 1987 brake booster as well?

Was searching everything I could find about my next project when I ran across this old question by Lariat 85. I've started the process by getting a new booster (O'Reilley #54-74211) for an '85 and the MC ( O'Reilley NMC 4007) for an '87. All was going great until I couldn't find adapters to go between my existing '85 lines and the new '87 MC.
I figured out the easiest way to hook it back up with my original lines was to swap the flare nuts and grab a "proportioning pressure regulator control valve" (E7TZ2C161C) off of an '87 in the yard so that the threads match up.
My question is whether or not anyone has used this part, and if so, did you gut it or leave it fully functional.
I guess I'm worried that if left functional, it might react poorly with the stock Proportioning valve down on the frame.
What are your thoughts?

 

A little additional info;
The flare nut thread sizes on the original cast iron MC are
Primary - 9/16-18
Secondary - 7/16-24

'87 MC w/ plastic reservoir
Primary - M18-1.5
Secondary - 9/16-18

I was able to find an adapter to go from 7/16-24 to the 9/16-18, but could not find one to go from 9/16-18 to M18-1.5

What I did notice was that the "Proportioning pressure regulating control valve" that is used on the '87s has the M18-1.5 to 9/16-18 threads, so all I did was change the nuts on my existing lines.

It would seem that now I have two devices that want to regulate the primary and secondary pressures!

My concern is whether they will play nice or cause problems. I had read something a while back about gutting the valve that mounts on the MC, but not sure if I should and would like to hear some opinions.

 

Why are you doing this? What is the advantage to using the '87 master cylinder?

 

I hate the old cast iron MCs, the cap always leaks just enough to corrode it and have rust everywhere. Every "newer" vehicle I've ever had has the plastic res w/ no leaks, so thought it would be a good mod.

 

My '67 hasn't leaked a drop out of the master cylinder cap but ut sits most of the time. With all the adapters here and there it seems like a lot of extra work for nothing. Maybe you are overfilling the reservoir? You are leaving space at the top and not filling it all the way top the top?

 

After lots of reading last night, it seems that I have the answer to whether or not I should gut the "Proportioning pressure regulating control valve". Here is an excerpt from the shoptech.com website and the first rule is what did it for me;

Proportioning Modifications

We could start this section by clearly stating that you should not modify your proportioning valve. But, what fun would that be? In all seriousness, making changes to the proportioning valve to effect brake bias should be left to those with the proper tools and measurement devices, but if you have tweaked your vehicle beyond recognition, this may be your only solution to restore a sense of proper bias to your braking system.
We’ll start here with three of the most basic rules regarding proportioning valve installation and selection.
1. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed if the factory unit is still in place. Proportioning valves in series with one another can do nasty, unpredictable things!
2. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed in-line to the front brakes. The effect would be to make your vehicle rear-biased before you could say “terminal oversteer.” Front brake line pressure should always be left alone – only the rear pressures should be considered for proportioning.
3. In all cases, the basic brake system balance needs to be close to optimized to start with. This is the only way that a proportioning valve can be effectively utilized. You should never assume that simply adding a proportioning valve will address all rear-bias conditions, as even the best proportioning valves must be well-matched to the target vehicle.


So, here is a pic of the valve that I pulled off of an '87



Here it is turn apart and the exploded view from Ford



And lastley, the stock '85 proportioning valve that I'm leaving on my frame rail.


The best thing about taking the adapter apart is that the first fitting (to the far left in the second pic) is simply a bushing that goes from the M18-1.5 to the 7/16-24 that my stock line has. I won't even need all of the rest of the parts.
I still need to get this all back together and bleed everything but I think all will be golden.
Stay tuned for a road test in the next couple of days.

 

Interested in this thread. I've change out my master cylinder twice, tried different lids, tried grinding/smoothing the lid surface, adding an extra gasket, tightening the holder as much as possible, etc. I really want a plastic screw on reservoir.


Did you have to modify the stock lines or fittings at all? Doesn't look like it.. maybe bent them since it seems the lines are reversed on the newer MC?

That metal fitting/part you took of an 87 that you took apart... did you gut it? What did you need to save from it? Do I have to find this part to make the conversion? Seems as though having it made it easier.

Anything else I need to know? Does the new MC bolt up to my booster without issue?

 

Interested in this thread. I've change out my master cylinder twice, tried different lids, tried grinding/smoothing the lid surface, adding an extra gasket, tightening the holder as much as possible, etc. I really want a plastic screw on reservoir.


Did you have to modify the stock lines or fittings at all? Doesn't look like it.. maybe bent them since it seems the lines are reversed on the newer MC?

That metal fitting/part you took of an 87 that you took apart... did you gut it? What did you need to save from it? Do I have to find this part to make the conversion? Seems as though having it made it easier.

Anything else I need to know? Does the new MC bolt up to my booster without issue?

 

Hey Coach,
I completely understand your frustration, it's the main reason that I decided to dig into doing the "resto mod"
I'll try to help as much as I can but two things come into play.
1. I did this 5 years ago
2. I was old at the time and now I'm even older

I didn't change my lines as I'm not the best with a flaring tool and as far as I'm concerned, brakes are something that I'd rather not screw up.
Regarding the part that you have a question about, I had searched extensively for an off the shelf solution to the miss matched threads and couldn't find one to purchase. It was simply through some good ol' noodling that I came up with the fitting/ thread adapter. It is the only part that was needed.

I'm sorry that I never reported back my seat of the pants findings at the end of this thread, but all is great! Stops just fine, no leaks, I can easily see fluid level, etc.
I highly recommend the mod.

 

Coach I did this on my old 86. It’s a cinch. Get about a 87 F-250 or 350 plastic MC and bolt that sucker on. All I had to do was unscrew the 87 proportioning valve and remove its innards.

1-2 hour (beer) job.