NOLA Speed and Style

Author Topic: Source for proportioning valve seals  (Read 461 times)

March 07, 2019, 06:51:50 pm

ORCoaster

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Source for proportioning valve seals
« on: March 07, 2019, 06:51:50 pm »
This is a wild shot in the dark I know.  But has anyone ever replaced those small washer like seals in the valve body?  I recently purchased a used valve body in hopes that the seals would still be OK but the internals were pretty full of sediment of some sort.  The one spring was compressed and stuck on to the valvestem and that misformed the seal to where it will not stay on anymore. 

Looked all over for this part, not sure if it is/was ever made as these valves are listed as non repairable.  I think I finally met something that was but only due to lack of parts now. 

Any one ever find new seals?  Not the O rings, the other one that is in there.   


Turbo and Exhaust finally on, Time for tuning!

Reply #1March 07, 2019, 11:56:35 pm

fatmobile

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Re: Source for proportioning valve seals
« Reply #1 on: March 07, 2019, 11:56:35 pm »
Hi my name is Craig and I hoard MK1 proportioning valves.
 How much did you pay for a used one?
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #2March 08, 2019, 12:22:08 pm

ORCoaster

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Re: Source for proportioning valve seals
« Reply #2 on: March 08, 2019, 12:22:08 pm »
I got mine from an old buddy and he didn't really charge me much.  But having the valve as a spare is only good if the little tiny washer like seals are good.  That is the part/parts I need now.  The body and red pistons are in perfect shape. 
If you really need a price do a PM and I will let you know.  But again, buddy price. 
Not really market price, or Ebay price.
Turbo and Exhaust finally on, Time for tuning!

Reply #3March 08, 2019, 10:52:43 pm

fatmobile

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Re: Source for proportioning valve seals
« Reply #3 on: March 08, 2019, 10:52:43 pm »
Right, and I can't really take one apart and tell if the seals are good enough to work.
 I have to put them in another valve and test it.
 I'm not really sure how they work or why the seals have little bumps.
 Other wise they kind of look like wheel cylinder seals.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #4March 08, 2019, 11:25:24 pm

ORCoaster

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Re: Source for proportioning valve seals
« Reply #4 on: March 08, 2019, 11:25:24 pm »
I think the little bumps are so some fluid can pass but when you really stomp on them, like panic time babe, the smooth flared edge catches the extra pressure and puts a crimp on the pressure to the rear brakes.  That keeps them from locking up.  Or at least tries to.  Having all that mass moving forward and the rears locked tends to push you in a circle.  That means more pressure up front and hopefully you can control the steering and keep it all in a straight line.

I hit the hardware store and found that the only type of seal that would come close to meeting the diameters and width was an O ring that was 1/4 ID, 7/32 OD, and a 3/32 inch width or thickness of the doughnut.  I am not sure this is going to do the job as it stops all flow through the body of the unit when I screw down the nut on the spring.  That is why I think the bumps as you call them allow some passage of air when the unit is assembled.  I was going to hook it up to the MC and see if anything comes out the bottom just for giggles.  Who knows I may stumble on a source or possible fix for these things at last.

I was told when I was shopping around that the reason these valves have no available parts is due to the liability issue for a rebuilder.  It is a safety item on the vehicle and should one rebuild it they become liable for its service.  Well you can't hardly see down that cylinder to see if it was scored up or not and you can't hone it out either.  So they just expected people to go buy another.  We can't do that anymore for our 40 year old cars now can we. 

I will report back on the use of the o rings in place of the washer like seals with the bumps.  I am not holding my breath that they will work even a little bit.  But for less than 2 bucks I figured I could try it over doing nothing. 
Turbo and Exhaust finally on, Time for tuning!

Reply #5March 11, 2019, 11:00:28 pm

ORCoaster

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Re: Source for proportioning valve seals
« Reply #5 on: March 11, 2019, 11:00:28 pm »
Well some of you are probably mumble I knew that, but the experiment with the O rings was a fail.  They do not allow passage of any amount of fluid.  So I will have to eyeball the four seals I have, find the best two and try them to see if they make the valve do right.  Back in a few days perhaps with a report. 
Turbo and Exhaust finally on, Time for tuning!

Reply #6March 14, 2019, 09:44:14 am

TylerDurden

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Re: Source for proportioning valve seals
« Reply #6 on: March 14, 2019, 09:44:14 am »
...they just expected people to go buy another.  We can't do that anymore for our 40 year old cars now can we...
FWIW, PP says they still stock the MK1 & MK3 proportioning valves...

https://www.partsplaceinc.com/vw-mk1-brake-proportioning-valve-15346.html
« Last Edit: March 14, 2019, 09:45:59 am by TylerDurden »

Reply #7March 14, 2019, 11:11:01 pm

ORCoaster

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Re: Source for proportioning valve seals
« Reply #7 on: March 14, 2019, 11:11:01 pm »
Last time I looked at PP the picture was of the older version that is in back of the axle.  I have the newer 81 style that is down on the front drivers fender.  Might need to call and get a better description if my rebuild using the best of the four seals I have available to me doesn't work well. 

At least I got it all clean inside and the little red pistons are not sticking on the o rings anymore.  Hope that it does OK. 
Turbo and Exhaust finally on, Time for tuning!

Reply #8March 15, 2019, 10:00:57 pm

fatmobile

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Re: Source for proportioning valve seals
« Reply #8 on: March 15, 2019, 10:00:57 pm »
 There's no picture in that link but it says it's for the early ones.
 You can get those for cheaper than $200 lots of places, last time I looked.
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #9March 15, 2019, 10:29:02 pm

ORCoaster

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Re: Source for proportioning valve seals
« Reply #9 on: March 15, 2019, 10:29:02 pm »
I actually had a used one sent to me from a guy that has lots of cars and a few trucks.  Cost me all of 22 bucks shipping included.  It just came with the caveat that it might not be any better than the one I already had.  And sure enough the piston was jammed up and the spring compressed down all the way.  And those are pretty solid springs.

I cleaned it up and was able to use one of the seals in it as it was better than one I had.  Seems that when the piston sticks on the spring, or is it the other way around?  The seal gets smashed into the piston from the backside and deforms it.  Makes it about a mm bigger and thus it becomes useless to keep fluid from going either way. 

Going to get some time tomorrow I hope to check for performance on the rebuilt component. 

Turbo and Exhaust finally on, Time for tuning!

Reply #10March 16, 2019, 08:41:49 pm

ORCoaster

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Re: Source for proportioning valve seals
« Reply #10 on: March 16, 2019, 08:41:49 pm »
Found the time and the sunshine today to reinstall the valve.  I had hard lines by passing it for awhile as a test. 

After the reinstall and the required bleeding of all four lines I have better but not the best brakes.  How do I compare?  I have my 81 Rabbit with the same system and it stops like no problem.  Pedal is high and tight, does not bleed down. 

The one on the Caddy is not so high, and slowly melts under pressure.  So thinking the new MC I put in is not holding up.  May have to talk to the Autozone folks for a return.

Dang I thought I was done here.
Turbo and Exhaust finally on, Time for tuning!

Reply #11July 10, 2019, 02:22:53 pm

BarrySon

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Source for proportioning valve seals
« Reply #11 on: July 10, 2019, 02:22:53 pm »
Looking for a source for the typical plain grade stock for a Model 81 -- nothing fancy like a curved buttplate.
Anyone have a current source?

 

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