Proportioning valve 'failure'?!

[Timbuick]

well, after removing the brake line from the proportioning valve after an hour wrestling with a very rusted union/joiner piece I nearly had a dumb accident that i thought i'd share so others don't do the same!

The brake system was allowing me to shuffle the car up and down the drive by giving me half the system after a rear brake line rusted thru and seemed safe enough.

After eventually removing the union at the proportioning valve I started the car up put her into reverse and thats when i realised I had no brakes. At all. None at this point i was moving backwards rapidly towards my wife's prized 1987 Benz 560SEC. Somehow I had the wit to stomp on the E brake and pulled up 3 feet short of a nasty bang to my GN and her Benz.
It was then that I noticed that the internal section of the proportioning valve had shot out of its body leaving me with no brakes!
Don't try this at home. I feel dumb and lucky at the same time

 

[charlief1]

LOL Sorry Tim but you have to admit it's kinda funny.:biggrin:

 

[Timbuick]

Yeah, its amazing what dumb things you can do in ignorant bliss!
uUnfortunately, I now think the prop valve is malfunctioning...

 

[Timbuick]

Can anyone verify if I have now got a faulty prop valve.
After the internal section got pushed out of the valve unit(see above) , I cleaned and refitted it.
However, I now still seem to have no front brakes and when I apply the pedal, fluid emits from the rear of the valve body.
I thought that the prop valve switched to front brakes only when a leak is detected in the rear brakes.
I now appear to have no brakes.

 

[charlief1]

Can anyone verify if I have now got a faulty prop valve.
After the internal section got pushed out of the valve unit(see above) , I cleaned and refitted it.
However, I now still seem to have no front brakes and when I apply the pedal, fluid emits from the rear of the valve body.
I thought that the prop valve switched to front brakes only when a leak is detected in the rear brakes.
I now appear to have no brakes.

It sounds like the internals are screwed up. They aren't that expensive so I'd go ahead and replace it since you're already there working on it.

 

[1quick6]

I agree. I'd never trust that thing again.
Here is a replacement option.

 

[Timbuick]

Ok guys, reckon you are right. Funny how simply changing a brake pipe turns into a marathon!

 

[1quick6]

On a 23 year old car, ANY project can turn that way. There are times that a nut/bolt will round off if I even look at it wrong.

 

[regan j]

try

bleeding all of your brakes starting of course furthest from M/C going to closest. the P/V valve has gone to the travel limit and wont return unless u bleed all of brakes and return to normal. hope this helps.

 

[charlief1]

If the valve is cast iron then just replace it. There was a recall on the cast ones if I remember correctly. Now if you want a less expensive one here's one off evilbay.

GM Disc/Drum Combination Proportioning Valve Street Rod: eBay Motors (item 250198100953 end time Sep-29-10 20:48:22 PDT)

 

[Pittsburghkid]

I beleive it's the same thing charlie posted but here it is $20 less than that and chromed.

GM Disc/Drum Combo Proportioning Valve CHROMED Aluminum: eBay Motors (item 350388388296 end time Sep-05-10 21:51:48 PDT)

 

[1quick6]

Interesting. I don't have any experience with those particular valves, but I'll let someone else try them and report back.

 

[Timbuick]

Thanks for all the heads up and recommendations, guys, much appreciated.
I'm going to replace the brake pipe, fully bleed, road test and then see what else it needs.:smile:

 

[Pittsburghkid]

Interesting. I don't have any experience with those particular valves, but I'll let someone else try them and report back.

Hopefully those valves aren't cheap for a reason and the person to try them is actually able to report back.

 

[charlief1]

Hopefully those valves aren't cheap for a reason and the person to try them is actually able to report back.

I will be ordering one of the disc-disc ones when I get the engine out. I just did the rear discs on my axle and now have to take the doors off and tranny out to build it.:biggrin: One of the members on here recomended these in the rear disc thread and it seems to work well for him.

 

[POWERBRAKEBOB]

Prop valves

Without the line in, the pressure pushed out the guts and some were lost. I rebuild them. Unfortunately, Delco ceased production of those valves. I started the use of them for the muscle car market when I was selling 55 chevy units to Danchuk. I was a Delco W.D. Eventually, the competition took my units and sent them to China to be reproduced. Those chrome ones are all Chinese copies. The 4 disc valves will double the pressure to the rear brakes.

 

[charlief1]

I think this is your swan song Bob. IF YOU'RE NOT A SUPPORTING VENDOR SO FRIGGING ADVERTISING!! Third time warned!