I have 73 F-100...have perty much decided to replace complete brake system. Front disc are done and back are in good shape but will replace cycliners anyway. What is the "proportioning valve" and does it need to be replaced or repaired? I haven't seen one is any parts books. How do I know if it is doing it's job?
Also I would like to buy some pre-bent line but don't want to pay $200+ for stainless steal ones....any other options?
Thanks Wesley

 

not a lot to go on here. the valve is hidden inside the Drivers side framerail somewhere close to the motormount tower. its important. it decides how much hydraulic pressure goes to the front brakes, as opposed to the rear. your front brakes stop your truck, and the rear ones keep it from 180'ing, basically. dont know what else to tell you. if your truck stopped in pretty much a straight line at a decent speed, it works. Ive never replaced one. if your back brakes, or your front brakes didnt work at all, that would be the first part i would throw at it if youve gone through everything else. dont forget the master cylinder plays a role in this as well, the large reservoir in front is for your front brakes, the smaller one closer to the firewall is for your rear. if that one is empty, you probably have a leaking slave in the rear which will be pretty obvious, and your rear brakes wont work.

you can buy straight brake tubing at any parts store, and its cheap. its actually also pretty easy to bend and flare yourself. be prepared to screw a few up, but its not all that difficult. you need like 3 tools. just ask someone at the counter. if they have half a brain, theyll get you going. if they dont, ask someone else.


cheers!

Jason

 

This is a good read.

http://www.inlinetube.com/pro_valves.htm

They have a great price on the valve if you beed one as well.


Here's an illustration of the 78/79 BPV

 

One thing to know about Ford's braking systems is this.

The rear shoes should come on first then the majority of braking is done by the front brakes.

That's whay It is important to have the rear shoes adjusted properly (within spec) so the braking system can work like it is supposed to.

 

I bought pre-bent regular Steel brake lines from NPD for a olt cheaper than the SS Lines. I plan on painting them before I install them and they will probably last longer than I will:-) NPD also sells the proportioning valve, but it sells for ~ $160 if I remember right, so I hope my old works when I get around to reinstalling it.

 

The most common failure with the prorportioning valve is that it sticks to one side or the other after a catastrophic leak in one of the brake lines.


In other words, you have a busted brake line that causes the porportioning valve to off center, lets say toward the rear. After the brakes system is fixed, the valve refuses to center itself and is stuck.

That's the most comon problem.

 

remember that when bleeding your brakes you MUST adjust the pin in the proportioning valve. Smaller trucks(150s etc) the pin must be held in while bleeding, and larger trucks the valve must be held out. This is the only way to properly bleed your brakes, and is why many Ford trucks have the 'classic Ford mushy brake pedal'. I've never had to replace one, but stuff happens.

 

All these years and I NEVER knew that!!

scroll up to picture... (please) is the pin you are talking about the "bleeder valve" pointing directly to the left? that thing is in such a hidden spot....

I dont think I have the problem, but i know someone who does...

 

I have never held out the pin in any of my F250s while bleeding the brakes and my trucks have always braked fine after bleeding. Now when I say brake fine, maybe I am not comparing it to what it should brake like???
I have never heard this either.
Think I'll dust of my old repair manual to see if I find reference to this.
Wow, learn something every day.

 

Yep, I can see where this was a problem for me in the past.

 

I can't count on both hands & both feet at least 3 times each that I have mentioned and posted this procedure on FTE in this forum.

I thought for sure everyone that has been here for a while knew this by now.

 

If I am using one of the popular one man bleeding kits does this mean that it suddenly becomes a two man job? Or three man if doing the ole brake pump thing?

 

Hey, BrokenRecord, is that you?

I made a tool like the one shown in the shop manual out of 1095 spring steel. (don't have a picture) It's really cool looking and works like a champ at holding out the metering rod.

From what I could tell using it tho, it doesn't do anything, it was a waste of time. Wonder what's up with that? Something wrong with my proportioning valve or something?

In my 1975 Ford Truck Shop Manual 12-01-9 it sez:
"On F100-F150-F250 (upto 6900 G.V.W.), E250 and E350 vehicles equipped with sliding caliper disc brakes, the metering rod must be pulled outward as shown in Fig.12. This is to allow the brake fluid to reach the caliper assemblies. This operation is particularly important if pressure bleeding equipment is being used."

My son still hasn't got a chance to finish his install of Xubuntu on my machine and so can't scan stuff right now. If you want pictures say so and I'll do it as soon as I can.

But Eff250's post blew me away. :/ I had to go get my service manual and look it up right-now... did I go and spend an afternoon making a tool that does the opposite of what's shown in the manual? :/ That's why it didn't work? :/

Nope!

So somethings backwards somewhere...
a) Eff250
b) my 1975 Ford Truck Shop Manual
c) just another "Ford up and changed it" thing

Which is it? :/

Alvin in AZ

 

 

What year manual is that, Dennis?

My 1975 Truck Shop Manual is different from that.

So is one or the other manuals messed up or did ford change something?
Again. ;)

Alvin in AZ