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General Information => Troubleshooting => Topic started by: ORCoaster on March 07, 2019, 06:51:50 pm

Title: Source for proportioning valve seals
Post by: ORCoaster 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.   
Title: Re: Source for proportioning valve seals
Post by: fatmobile 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?
Title: Re: Source for proportioning valve seals
Post by: ORCoaster 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.
Title: Re: Source for proportioning valve seals
Post by: fatmobile 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.
Title: Re: Source for proportioning valve seals
Post by: ORCoaster 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. 
Title: Re: Source for proportioning valve seals
Post by: ORCoaster 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. 
Title: Re: Source for proportioning valve seals
Post by: TylerDurden 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
Title: Re: Source for proportioning valve seals
Post by: ORCoaster 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. 
Title: Re: Source for proportioning valve seals
Post by: fatmobile 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.
Title: Re: Source for proportioning valve seals
Post by: ORCoaster 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. 

Title: Re: Source for proportioning valve seals
Post by: ORCoaster 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.
Title: Source for proportioning valve seals
Post by: BarrySon 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?
Title: Re: Source for proportioning valve seals
Post by: Chuck1978 on February 29, 2020, 09:56:53 am
I went through lots of hassles with these old proportioning valves.... They are I believe a combination proportioning valve & also rear drum brake residual check valve (the red anodised plunger shafts with the springs & funny looking bumpy washer on the end)?

On my wife's 82 pickup, I always had trouble bleeding & getting fluid to the rear brakes, after a hose failure, & later a rusted line replacement.
Then I was out of commission for 6 months at the end of winter 2019, post-knee-surgery, & my 82 pickup's brakes had all gone to crap after sitting all winter& to early summer.
I replaced every part in the system over a few attempts, booster, master cylinder TWICE, wheel cylinders, hoses, calipers, probably close to a gallon of brake fluid just bleeding over & over.

Finally the 2nd time I tore apart the proportioning valve for a cleaning/reassembly, & then bled it extensively from the valve, then I finally got some better braking back...
Careful as the lines are tough to get to when installed, and very tough to get threads started properly on. Make sure your flare nuts are in god shape, or else fab up new hard lines from Nickel-Copper bulk tubing rolls, + stainless steel fittings. The NiCu lines will allow much easier alignment of starting the threads.
Also, I was primarily bleeding them from cracking open the hex cap o-ring seals after initial bleeding from the lines.  DO NOT remove these on the vehicle, only loosen. You WILL NOT have much luck fighting the springs on reinstall when reaching way down there thru everything.
The red anodised plunger pistons get all kinds of gunk buildup between them & the springs, & get seized onto the o-ring/plastic seal/guide fitting in the steel hex cap, & render them non-functional.
BEWARE...when these things become freed up, they will launch like a cannon
Title: Re: Source for proportioning valve seals
Post by: Chuck1978 on February 29, 2020, 10:12:23 am
The centering piston at the top is the safety valve feature to cut off one circuit of brakes in the event of a catastrophic leak.
The problematic red plunger assembly is the rear drum residual check valve assembly and also proportioning valve to limit a percentage of fluid traveling to the rear brakes. These are built into the master cylinder on most other vehicle applications. Drums require a few psi of pressure constantly on their lines to achieve quick brake actuation. This is the purpose these springs & plungers serve.
Title: Re: Source for proportioning valve seals
Post by: Chuck1978 on February 29, 2020, 11:12:35 am
I have a bunch of photos of these dismantled, but both this forum and vwvortex do not post up here to host photos. There are Photobucket photos on this, but you get a blurred watermarks version at least viewing on mobile, I think desktop site they might still work on Photobucket

https://forums.vwvortex.com/showthread.php?4294532-OEM-proportioning-valve
Title: Re: Source for proportioning valve seals
Post by: Chuck1978 on February 29, 2020, 11:24:51 am
Here we go. Mine + eBay spares, to build one decent unit, lower plunger assemblies are still together, meaning they are seized!
(https://live.staticflickr.com/65535/49599950898_2dbf88c757_k.jpg) (https://flic.kr/p/2iyYHnd)VW Mk1 Rabbit Pickup brake proportioning valves179612151a (https://flic.kr/p/2iyYHnd) by chuck_lambert78 (https://www.flickr.com/photos/17633945@N00/), on Flickr
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on February 29, 2020, 11:13:04 pm
Yeah, don't you just hate how those red pistons get stuck in the end of the nut assembly.  Once you get them the tiniest bit loose they go shooting in some unknown place in the shop. 

I was able to obtain a second proportional valve from another VW parts collector, Thanks Dave, but I wonder if my pistons are still hanging up.  I just don't get the stopping power from the rear brakes.  That leads me to think that they are not staying charged and when I step on the brake pedal most of the first stroke ends up setting up the brakes for a proper stop.  But who double pumps brakes? 

Going to fiddle with them again when the weather warms up.
Title: Re: Source for proportioning valve seals
Post by: fatmobile on June 09, 2023, 10:32:56 pm
 Someone on the vortex found a source for the MK1 brake proportioning valve seals:
https://www.vwvortex.com/threads/brake-proportioning-valve-mk1-rabbit-golf-rebuild.9535470/#post-115967790

 They are the same as on some 92-95 dodge cars:
https://www.musclecarresearch.com/mopar-4485829-brake-valve-seal-kit
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on June 10, 2023, 10:39:26 pm
What a deal, 15 bucks for parts that I have searched for all over the place.  I even have gone to hardware and auto parts stores hoping to at least get a couple of them.  I have several valves and now they can all be rebuilt.

I was buying them from people who are scrapping their cars because they are generally easy to cut off and send in a small USPS box.  No one wants them unless you do when your brakes don't seem to be able to bleed easily or the rears don't seem to be working and the front discs are smoking hot to the point you can smell them. 

Thanks a bunch for this. I already ordered two sets. 
Title: Re: Source for proportioning valve seals
Post by: fatmobile on June 12, 2023, 10:47:49 pm
As soon as I saw that post, I thought of you and your search for a good one.
 And my small stash of them with the seals getting older.
I bought a couple sets too.

In the picture, the dodge proportioning valve looked just like the VW one.
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on June 13, 2023, 09:52:47 pm
This had me wondering if we could just have bought that valve if we would have known it was being used in those vehicles.

The price is way too high.  I like the 15-dollar diy fix. 
Title: Re: Source for proportioning valve seals
Post by: srgtlord on June 15, 2023, 11:00:53 am
FYI the MK1 and MK2 proportioning valves are a different diameter. I bought a set of seals that were brake fluid rated based on a discussion on vwvortex but the orings were bigger. If I ever have to go through the headache of finding replacement valves again Im just jerry rigging an mk3 prop valve with a fixed height as they can still be found new. Just have to bend a coat hanger to keep the variable adjustment in place. I had that on my 1990 mk2 golf as it came stock in those years and the variable spring broke off. The coat hanger trick was on there for well over 50k miles.  It was mounted on the rear axle beam but with a fixed height you can put it anywhere
https://www.autohausaz.com/pn/13597674-1H0612151?utm_source=google&utm_medium=cpc&utm_campaign=feed_VW&gad=1&gclid=Cj0KCQjw7aqkBhDPARIsAKGa0oLCg4algoi0L5Wq5Dy-861wgjPdKM3bEkGafugvdthQu56AucSHGEUaAiIPEALw_wcB
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on December 24, 2023, 07:09:34 pm
Digging up an old thread only because the VW part number matched my search.  And this is good stuff.

Today I spent a bit of time at the workbench tearing into the valve that was on my pick up.  I have been noticing that the brake pedal is low and the stopping power is less than it needs to be if I am carrying any amount of weight.  Say 300 lbs plus myself.

So, after disassembly I got into the inspection part and found that the one side of the valve body where the lines would connect from the rear brakes was pitted.  So that is likely why I am missing the ablility to really get a good pedal and maybe why the pedal I do get will bleed down after a while if I push and hold on it. 

I put on another valve body and plugged the lines to the back and I don't have that bleed down effect now so I am pretty sure I don't need a new MC, booster or cylinders.  Most of them have been replaced in the recent past anyway.  That doesn't always mean they are still good.  Just look at those posts about multiple MC fails and the trouble they had getting them to bleed at all.

I hope to swap out the valve on the truck now with another that I verified is good and has new seals in it.  It sure is a pain to replace that sucker.  Terrible location and why?  Maybe I will relocate it as I have to do work on it and that entails new lines to the back.  I may keep you posted, but maybe not.

Merry Christmas everyone. 
Title: Re: Source for proportioning valve seals
Post by: fatmobile on December 25, 2023, 12:30:50 am
 I got a couple of those kits.
 A couple of mine should get rebuilt before they start to corrode.
Pretty easy once they are off the car.
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on December 25, 2023, 05:50:31 pm
I was looking for information from you on the proper orientation of those ribbed seals that go on the pistons.  I tried the way I thought, ribs to the inside of the valve, and got no joy from that.  So I had a second valve and put the seals against the valve body, and ribs against the piston.  Now that blocked off the fluid to the rear lines and that for sure is not right. 

I think after I took the first valve off and saw the pitted nature of the bottom on the valve body I figured out why I didn't get success the first time around.  Fluid was freely passing around the seal so of course it didn't do any of what it was supposed to do.  Another valve and a proper fittment on the seal should yield success.  At least that is the logic.  VW's can defy that.
Title: Re: Source for proportioning valve seals
Post by: fatmobile on December 26, 2023, 12:38:08 am
 Are you paying attention to how the old seals were sitting before taking them apart?
 It's been so long since I took one apart and have been too distracted these last couple days to dig into the brake stuff bucket.
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on December 28, 2023, 09:47:53 pm
Well, my problem was that it was a year ago that I tore the valve apart and the seals were one mushy mess down in there.  So no way to know what was what and how it was orientated. 

When I got a second valve, hoping to get better sealing it too was nasty.  So those got cleaned off, bagged up, and thrown in the cupboard.  Then along comes the reseal kit information and I am like, great I can finally pull the one off the car and swap in a rebuilt one.  I should have pulled the one on the truck, noted how it was put together, and then rebuilt but I didn't have the time to do that.  I had time to rebuild one weekend and wait for better weather. 

That happened a couple of weeks ago and I just swapped them over hoping for the best.  I did look at various forums and the Muscle Car site where I bought the kit.  They had some pictures to look at so I tried it that way.  But putting good seals in the bad valve body didn't help any and my success was nil if not worse once I put in half a day getting it in and bled and all. 

Now knowing what I know I rebuilt another valve and will try it when the weather gets nice.  Till then I am driving the hybrid Pickup and enjoying the ride and in-town mileage. 
Title: Re: Source for proportioning valve seals
Post by: fatmobile on December 29, 2023, 08:39:26 pm
 oh, quite a journey to finally get good brakes.

 This project is moving up my list, the brakes on (Pa)tina are a little mushy.
 I have been hoarding these valves.
 Seems like every time I worked on someone's rabbit brakes, I'd lose another one of mine.
 Their valve or seals would be bad.
 Sometimes I could clean them up and get one working but usually I'd have to dig into my parts hoard.

But I still have some left so I can rebuild a couple, then swap one in.

I like to take the car out to the gravel road, drive slow then hit the brakes and see how they slide.
 See if all the wheels are helping to stop,.. evenly.
Title: Re: Source for proportioning valve seals
Post by: ORCoaster on December 30, 2023, 12:24:54 pm
You are where it gets cold enough for snow are you not?  That might be better to use than a gravel road.   A big flat parking lot perhaps. 

Title: Re: Source for proportioning valve seals
Post by: fatmobile on December 31, 2023, 02:16:02 am
 Oh yeah, in the winter I don't have to go far to find a slick spot to test the brakes on.
Or most winters anyway, I can use the street.

 But gravel allows me to be going a little faster and see how the tires grab and when.
 Sometimes a slick road doesn't grab them enough, it doesn't pull on them and test the wheels stopping ability.
 And you don't have to be going very fast to have the prints from the rear tires run over the tracks of the front.
 making it hard to see where they locked up.
 
 I'm about three blocks from gravel road.
 I don't do it often but sometimes wonder what that old guy thinks about me
driving slowly down his road and locking them up,
getting out to check then doing it again with another walk around.
 Or what the next person thinks about the odd tracks in the road, ha.