Proportioning valve issues

[aknotts]

I am trying to get the brakes working on a 1973 Plymouth Satellite and can not seem to get any fluid to the back brakes, or even out of the back line on the proportioning valve. I have read through the threads and have some basic questions before I declare it to be bad, It is the only part in the system that is not new.
Power Front disc, rear drum setup, original to the car. I have a parts car that has the brake system in tact and get the same results on it, not an issue as I don't need any of those parts but makes me wonder if I am doing something wrong.

No engine in the car so I have no vacuum to the booster. Trying to get the brakes working so I can drag it around the corner to a friends and drop the new Motor/Tranny in.

Issue:
1: If I pull the brake line going to the rear brakes completely off the proportioning valve I have no fluid coming out either by gravity or when the pedal is pushed.

2: If I pull the line from the Master cylinder to the proportioning valve, at the valve end, I have fluid and some pressure there, both front and back. Although it seems the front has more pressure than the back.

I have tried holding in the little button on the front of the valve while pushing the pedal, same results, also tried holding it in the out position.

3: Front brakes are working fine although they may still have some air in the lines.

The car has been in resto mode for about 2 years so all the lines were empty.

Questions
1: Shouldn't fluid pass through the proportioning valve via gravity if there is no line on the outlet? It is mounted below the master cylynder.

2: Does this indicate a bad proportioning valve, and can it be fixed or do I need to purchase another one, and if so, the parts car must have a bad one also?


Thanks in advance.

 

[RustyRatRod]

I know......this is gonna sound completely stupid, but it's 100% the God's truth. I was havin that problem once on a VW years ago at a shop where I worked. It ended up being a small pebble IN the brake line going to the rear brakes. How the hell it got in there is anybody's guess. That doesn't sound like what you have goin on, but I just thought I would throw it out there. Your deal sounds more like the proportioning valve stopped up or stuck. Have you got another one you can try? If not, they are pretty cheap. Have you used air to blow through the rear brake lines to be sure they are clear?

 

[aknotts]

I did blow through the back brake lines and the pebble thing is not that far fetched, seen some weird stuff myself. The issue is however I am not even getting any fluid out of the valve, I have read a few threads that mention it's purpose is to shut of the back brakes in case of failure so you still have pressure to the front to stop. What I am wondering is if it is doing what it is desinged to do and if so how do I get the back brakes pressurized to allow it to work. Or is it just bad.
I do have another one on the parts car and it is acting exactly the same, on the parts car, so I either have 2 bad ones or I am and idiot and doing somthing wrong here.
But thanks.

 

[D575]

Get a good bleed on the master cyl. first. Not just "some pressure" it should really squirt out of the master cyl.

 

[aknotts]

Get a good bleed on the master cyl. first. Not just "some pressure" it should really squirt out of the master cyl.

What is the best way to accomplish that?

 

[D575]

What is the best way to accomplish that?

 

[aknotts]

Will try that tonight. Thanks.

 

[YY1]

If you're getting fluid out of the m/c line (remember front chamber is for REAR brakes), but not from the prop valve, I sure would suspect the prop valve.

 

[aknotts]

If you're getting fluid out of the m/c line (remember front chamber is for REAR brakes), but not from the prop valve, I sure would suspect the prop valve.

Should I be getting fluid from the prop valve rear line via gravity, with the master cylynder full and open and nothing conneted to the prop valeve outlet?

 

[RustyRatRod]

I certainly think so. I've gravity bled an assload of cars through the years and never had difficulty getting flow to the rear brakes, unless something was wrong.

 

[Someotherguy]

I had the exact same issue with my 73 RR..no fluid to the rear brakes...I went as far as taking the guts out of the proportioning valve and cleaning them, same problem, no fluid...So i found another p-valve off a local junk d250 van...that fixed the issue...

IMO, the p-valve you have is toast...replace it...

I have read that the mid 70's ramcharger trucks have the same valve...The d250 valve i got just needed a reducer coupler so one of my brake lines from the master cylinder would fit...

 

[aknotts]

I thought so also, I guess I will pull the damn thing out, disassemble and clean, maybe replace orings tonight, rebleed everything and see whre I am, I would buy a new one but that puts me back another week before I can drop in motor and tranny, which are both completly redbuilt and ready, and starring at me, mocking me even. I can hear them at night making fun of me.
Nothing available locally that I can find. If this doesen't work I will order one online and spend some time with the wife this weekend, I guess.

Thanks everyone, I will update tomorrow.

 

[RICHIES ARMOR]

Sounds like you need to get that motor and trans installed and teach it who's boss!!!

Richie

 

[STROKED71]

i had the same problem with my prop valve, put it on a vice, took it apart, had trash in it, used lots of wd 40 and air, also those valves are made of steel and they do rust, hope this helps

 

[aknotts]

OK, I took it off the car, cleaned it and reassembled, same issue, I beleive it is toast. The part does not seem to be available anywhere either so I guess I am going to have to go aftermarket, I really did not want to have to modify the lines but I guess I will have to.
Any suggetions on aftermarket, maybe adjustable. Will these work with my stock master cylynder?

Maybe this one:
Wilwood Brake Proportioning Valves 260-11179
http://www.summitracing.com/parts/wil-260-11179/overview/

Any other suggetions, Front disc, rear drum.

This is very frustrating.

 

[D575]

OK, I took it off the car, cleaned it and reassembled, same issue, I beleive it is toast. The part does not seem to be available anywhere either so I guess I am going to have to go aftermarket, I really did not want to have to modify the lines but I guess I will have to.
Any suggetions on aftermarket, maybe adjustable. Will these work with my stock master cylynder?

Maybe this one:
Wilwood Brake Proportioning Valves 260-11179
http://www.summitracing.com/parts/wil-260-11179/overview/

Any other suggetions, Front disc, rear drum.

This is very frustrating.

Do you have a good squirt from master cylinder front and back ? if not it's either not bled right or it's bad. This is going to sound stupid but , if you have fluid to the valve and any kind of pedal [feel pressure] when you push the pedal. stomp on the pedal as hard and fast as you can. then start bleeding again, but this time don't push it all the way to the bottom. and do it slowly as to not upset the prop. vlv. but still if you don't have a good squirt from the master cylinder none of this matters. I've seen master cylinders where just one side didn't work. if you tore apart the vlv. and it's doing the same thing it's probably not the vlv.
Did you bench bleed the master cylinder ?

http://www.ebay.com/sch/i.html?_trk...runner+proportioning+valve&_sacat=0&_from=R40

http://www.summitracing.com/search?keyword=proportioning valve&dds=1

 

[aknotts]

Do you have a good squirt from master cylinder front and back ? if not it's either not bled right or it's bad. This is going to sound stupid but , if you have fluid to the valve and any kind of pedal [feel pressure] when you push the pedal. stomp on the pedal as hard and fast as you can. then start bleeding again, but this time don't push it all the way to the bottom. and do it slowly as to not upset the prop. vlv. but still if you don't have a good squirt from the master cylinder none of this matters. I've seen master cylinders where just one side didn't work. if you tore apart the vlv. and it's doing the same thing it's probably not the vlv.
Did you bench bleed the master cylinder ?

http://www.ebay.com/sch/i.html?_trk...runner+proportioning+valve&_sacat=0&_from=R40

http://www.summitracing.com/search?keyword=proportioning valve&dds=1

I do have good pressure from both sides of the MC, I am going to walk through the entire process one more time though, this time I will fill the back brake lines before hooking it to the valve though.
Even after cleaning and reassembling the valve, off the car, I could not get any fluid from the input to the output on the back side. I would think it would be able to move fluid through there on the bench, am I wrong?

 

[D575]

I do have good pressure from both sides of the MC, I am going to walk through the entire process one more time though, this time I will fill the back brake lines before hooking it to the valve though.
Even after cleaning and reassembling the valve, off the car, I could not get any fluid from the input to the output on the back side. I would think it would be able to move fluid through there on the bench, am I wrong?

Did you blow through it when you had it apart ? if the valve is in the position where its blocking the port then no. that's why I mentioned the stomp. back in the 70" when we had issues with proportioning valves and brake warning lights , especially after doing brakes. a good stomp would reset the valve. but you have to have some kind of pedal first. I really thought it was the master cylinder. I've never really seen a prop. vlv. go bad. [ that I can remember]

Are you sure that line is clear and not kinked or crushed somewhere ?

 

[D575]

Try holding the button on the vlv. while bleeding..starting to sound like a 3 person job. I know you said you tried this. clamp it down if you have to, once you get some pressure behind it it should stay open.
If you can take the valve spool out.take it out and bleed then stick it back in and bleed it again.

 

[rebootej]

I think ive got a simular problem, light came on after bleeding the brakes. But i have fluid all the way around, and good pedal pressure. Which way do you hold the button? In?