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411-412 rear brake pressure regulator
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raygreenwood
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PostPosted: Sat Feb 18, 2017 6:02 pm    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

titan3c wrote:
As Ray mentioned PMB rebuilds these regulators. I just checked them out, and they do a complete rebuild for $169.00. So I'm planning to do that


Sorry...it been busy...working.

The kit should work fine. I have confidence in the kit materials because PMB does brake parts well.

I would really like to find out....and I will.....if PMB kits have a replacement nylon valve part for the factory poppit valve inside of the main valve body. I will find out next week.

The issue is....that the original nylon part was made of nylon 6. So.....when brake systems sat neglected.....and the fluid does what it does....absorb moisture.....the nylon needle/poppit valve just turns to mush. So the rebuild kit needs to have one.

The rebuilding sequence....I have rebuilt quite a few of these back when you could get kits....and later when I had new cups made.....is like this...and its a total rebuild with new gasket and o-ring between spring section and valve body:

1. Clamp the valve body in soft jaw vise
2. Take the big cap off with a wrench
3. Pull out the valve assembly....put it aside.
4. Flip the cylinder so the spring section and valve body are clamped held together.
5. Remove the 4 allen head screws. Slowly open the vise to unload the spring.
6. Clean everything, repaint the outside of the valve body and spring housing (mask the threads and openings)
7. Using 1000 grit or better...lap the bore inside of the valve body and clean away all debris .
8. Put silicone grease in the spring cup....both sides....put a new gasket on the spring housing....clamp it all back together and install the four allen head screws.
9. Using a flare wrench and holding the valve assembly in a soct jaw vise by the tail....disassemble the valve unit. Clean it well.
10. Install a new nylon pintle if the kit has one....along with the spring and brass hex.
11. Heat the new cup in boiling water......and carefully work it onto the valve body
12. Install the new o-ring.....lube lightly with brake paste.
13. Reinstall the valve in the bore.
14. Put a new o-ring on the cap
15. Reinstall the cap. Done.

The trickiest part is the sealing cup. It has to be pliable and you need to be carful not to rip it.

The torque specs are in at least two books I have. I will post specifics when I can. Ray
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titan3c
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PostPosted: Sun Feb 19, 2017 5:40 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Ok, Thanks. On the PMB web they show a picture of the parts in the rebuild kit, and also they describe in detail what they do on a rebuild. They also state they set the adjustment at 525. They also describe briefly why this part is needed----which you have previously described in more detail.
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PostPosted: Mon Feb 20, 2017 7:23 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Have a question---this may sound elementary, but I learn more by admitting stupidity, than pretending to be smart.

Having never removed the pressure regulator, I can't help but note that the two brake lines--left and right(to MC, and right brake)will still be protruding into the regulator connection after completely loosening the nut. There is no room for right or left movement. How do these lines clear the connection? I understand the top line going to the left brake will come clear, by just dropping the unit when disconnected from the mounting bolts.

Am I making something hard out of something easy? Will they work loose, or is there some technique in removing this unit. Bob
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PostPosted: Mon Feb 20, 2017 7:49 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

titan3c wrote:
Have a question---this may sound elementary, but I learn more by admitting stupidity, than pretending to be smart.

Having never removed the pressure regulator, I can't help but note that the two brake lines--left and right(to MC, and right brake)will still be protruding into the regulator connection after completely loosening the nut. There is no room for right or left movement. How do these lines clear the connection? I understand the top line going to the left brake will come clear, by just dropping the unit when disconnected from the mounting bolts.

Am I making something hard out of something easy? Will they work loose, or is there some technique in removing this unit. Bob


Not a stupid question at all.....and....a perfect observation of one of the annoyances of how this thing is installed.

The only way(s) to get the unit out is

A. To either slightly bend one line.....and then yes.....it makes it a pain to reinstall.
B. Choose the easiest line to access.....and loosen the bent over hold down tabs that hold the metal line to the chassis......and take it loose back to where is meets up with the soft brake hose.

While "B" sounds like a mess.....its not really any worse. Because of what you are taking out of the system.....you will need to completely bleed the rear circuit.

So.....if you are doing that.....this is a perfect time to go ahead and replace the rear brake hoses if they are not recent ...and these are running between $6 (Beck Arnely) and $8 (Wagner) or $9 (Raybestos) at Rock auto........and rear wheel cylinders are cheap as well.

This is also a perfect candidate job to slap together a pressure bleeding kit....AND.....buy a set of speed bleeders....or at least a pair for the rear

I say these things because the pressure regulator can make bleeding a bit more difficult when the rear circuit is dry.

This is because.....the 411/412 system....being a bit circuitous is already hard to get the bubbles out of. It responds best.....to having the bleeder screws just barely cracked open....with the threads sealed with teflon tape (speee bleeders come with thread sealer on them).......so that every stroke of the MC builds pressure trying to squeeze the fluid out of a barely open bleeder valve.

The speed bleeder with its check valve and barely cracked open magnifies this effect.
But....once you start getting real pressure and the pressure regulator valve starts moving a little its a little harder to get fluid flow past until the bubbles move out. Ray
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PostPosted: Mon Feb 20, 2017 9:31 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Thanks Ray. I'll go loosening the right brake line----that's about what I figured would have to be done.

Didn't know there was such a thing as "speed Bleeders", so I will do that also.

Not sure about the speed bleeder kit. Is that something that can be purchased or rigged(DIY)?
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PostPosted: Mon Feb 20, 2017 11:23 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

OK I know what a pressure bleeding kit is. Don't know where my mind had drifted off to. Bob
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PostPosted: Mon Feb 20, 2017 11:37 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

titan3c wrote:
Thanks Ray. I'll go loosening the right brake line----that's about what I figured would have to be done.

Didn't know there was such a thing as "speed Bleeders", so I will do that also.

Not sure about the speed bleeder kit. Is that something that can be purchased or rigged(DIY)?


Speed bleeders are worth every penny.

Here is their site http://speedbleeder.com/ You can buy these direct or from numerous dealers online.

Do not go by the application charts from some of the other sites. A few of them while they post usable part numbers for VW and Porsche...do not know the specific issues. For example...Russell performance lists a part # for the front caliper of the Porsche 914-4...which is the same caliper as type 3 and 4 cars....that while it works....is about about 5-8mm shorter than it really needs to be. It makes putting a 7 or 8mm wrench on it impossible and you can only access it with a socket.

The factory 914/411/412/type 3 front caliper bleeder screws were a special longer version.

Here is the bleeder screw chart from Speed bleeder's site with the proper bleeder screws circled and labeled for type 4 and type 3 cars

Image may have been reduced in size. Click image to view fullscreen.


These screws have a spring and ball check valve in them. So all you do is crack it open slightly....attache a hose to go to a container....and it does not have to be submerged...and just get in and pump the brakes.

No assistant no extra work. The ball check valve closes when you let off.
the pedal and does not allow air to suck back in.

The rear part # SB6100 (which means 6mm x 1.0)...typically run about $7 each from numerous sites. The front SB7100 (7mm x 1.0) also run about the same.

You only need one speed bleeder screw each for the front calipers. It goes in the top position.

The "pressure bleeder" kit.....is something you can make. You can find decent pressure bleeder kits for between $50 and $100....but you can make one for a bit less than $50.

If you make it right or buy a decent one...you can use it for any vehicle.

The tough part for some master cylinders is finding a spare simple cap for the reservoir to attach a hose to. My 2012 golf has this issue. All of the caps made for it were made to have the fluid level sensor in the cap.

I finally broke down and bought this tool...a universal cap that fits ANY brake reservoir with a round opening....and added it to my home made brake bleeder set up.


In the long run....I actually spent...once I bought a simple pressure sprayer from home depot (about $12)...hoses, clamps, a cheap pressure gauge, tees and a bleeder valve....close to $40 on my pressure bleeder. If I had to do over...I would just buy the model in the link from ECS tuning

This is a great deal for about $10 more...and if you buy the universal cap assembly...bringing up to about $68...you get free shipping. No running around looking for parts and marginally more in cost...and this one is probably in about the top 3 on the market....AND....you can be sure that the seals and o-rings are EPDM so that brake fluid does not eat them Wink

https://www.ecstuning.com/b-schwaben-parts/3-liter-european-pressure-brake-bleeder/007237sch01a/

And...spend the extra $20 for this part

https://www.ecstuning.com/b-schwaben-parts/universal-adapter-kit-for-brake-bleeding/007311sch04a/

This part is deceptive in the pictures. It is actually large In fact...before you buy this part let me make sure it will fit on the 411/412 reservoir against the firewall.

Its about 3" in diameter....to allow you to fit on large opening reservoirs.....from 3" down to about 3/4"and comes with a chain and "J" screw so it literally clamps onto and compresses onto the master cylinder that the reservoir fits on. I will find out today if it can be bolted to the type 4 and type 3 reservoir.

In this way you can use it to bleed virtually any system.

If it does not fit the 411/412....save the $20 and buy this part

http://www.vwispwest.com/131611349A.html?p=YzE9MTg0

ISP west shows out of stock

https://www2.cip1.com/ProductDetails.asp?ProductCode=VWC-111-611-349
CIP1 has it

Probably many others have it as well.

Its a spare reservoir cap. Drill a hole in it..install a brass hose barb that fits the hose from the pressure bleeder and clamp it. Use a nut on the inside to seal the barb so it does not leak.

You will need a skinny barb so look for one with a 1/8" NPT thread inside and a 1/4" barbed fitting on the outside. Clamp it to your hose, screw it on...and you are ready to pressure bleed.

Do not confuse pressure bleeding with vacuum bleeding using the kit from Harbor freight or others or using the mighty vac pump.

Pressure bleeding is far superior. You pressurize the fluid reservoir to about 10-12 psi. Do not put any more pressure on it because you have un-clamped fluid hoses. Many water cooled vehicles can run 15-25 psi of fluid pressure. You just need about 10psi....then open a bleeder screw and get in and pump slowly...and the pressurized fluid makes for quick and effective bleeding. Ray
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PostPosted: Thu Feb 23, 2017 5:42 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

OK, I removed the regulator, and managed to install a "T" connection for the time being, Also I ordered the speedbleeders.

Now I'm debating whether to order a rebuild kit or have the regulator rebuilt. Just because of the cost factor. My main concern in doing a rebuild kit is I'm lost on how you make the spring adjustment to 525. Wouldn't you have to have some pressure in the unit? That part in the process has me confused.
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PostPosted: Thu Feb 23, 2017 6:30 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

I'm debating whether to order a rebuild kit or send the regulator in for a rebuild. Just because of the cost.

My only hang-up in doing the rebuild myself is how to set the psi(525) on the spring pressure?

I have the regulator off, and managed to install a "T" connection for the meantime.
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PostPosted: Thu Feb 23, 2017 9:03 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Dont worry about the pressure setting. If it was correct before......it will be either spot on or very close to correct when you get it back together.

Why?.......a couple of items......
1. What do you suppose the chances are this has been tweaked with?... take a look at the locknut and adjuster screw on the long part of the body. Does it still have the anti-tamper adhesive or putty on the adjusting screw? It will be blob of white, blue or yellow adhesive putty on the locknut.

2. You are not changing the piston......just the seals.....so nothing inside changes dimensionally.

3. The spring length setting will stay the same. For quite a while......because I had no gauges.....I simply put new seals inside of these and reassembled and they functioned fine.

Take the large hex cap out....and pull the piston and seal assembly out. Shine a light inside.

This is the same rebuild criteria as a master cylinder. If its hideously crusty rust inside....there may be issues. Take a dowel wrapped with 600 grit minimum and work the inside. If it clears up all but a few fine pits.....you are good to go.

And......bear in mind....that PMB is going to to do largely the same thing....maybe with a hone brush. Whether you decide to rebuild it yourself or have PMB do it.....you need to do this assessment....and once the assessment is done.....the unit is largely ready to clean and reassemble.

The biggest trick is getting the seal cup on. You need to heat it until its soft. Working it on is a tedious job not to tear it up. Not difficult....tedious.

Later if you want to check the operation.....you can get a 0-700 psi gauge from McMaster carr for about $10. You should buy two.

You simply plumb the gauge into the inlet side of the regulator with a Tee fitting......connected to the master cylinder. Then.....connect the left and right outlets to tubes leading into a catch bottle. Bleed the rear circuit this way to make sure the regulator is free of air.

Then plug one side of the outlet of the regulator....left or right. Plumb the second gauge into the other outlet.
Have someone start pumping the brakes hard.....standing on them at the end of the stroke.....while you watch the gauges. You should see the inlet pressure and outlet pressure rise equally......until it hits 525 psi.....then you should hear an almost inaudible "click".....and the gauges should both read 525 psi.......but as your assistant keeps up pressure and increases it.....ONLY the inlet gauge should continue to increase pressure. The output gauge should stop at 525 and hold.

When you let off the brakes.....you should hear that click again and both pressure gauges will drop.

If its incorrect.....you crack the locknut loose and put the allen key on and make about 1/4 turn adjustment at a time.

If you do not have assistance or do not want to do this.....its worth it just to have them rebuild and reset your unit.

Also....looking at what PMB does....they zinc plate the entire unit. This goes a long way toward bringing up tolerances inside the bore after cleaning. They also paint it.
For $169.....thats a pretty good deal. Ray
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PostPosted: Fri Feb 24, 2017 4:41 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Yep----I've had the same thoughts. It's a pretty good deal for $169.00.
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PostPosted: Fri Feb 24, 2017 8:03 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Yep.....if I had a rebuildable core i would take advantage of it by at least buying a kit...but probably by buying the whole rebuilt unit.
Ray
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PostPosted: Sat Mar 04, 2017 11:34 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

So....I have been thinking about this much more.

Long ago I installed...on my 412 four door....an aftermarket brake regulator because I could no longer get parts for rebuild of the brake regulator.

As mentioned...at one time....right around 1991-92....when I lived in Atlanta Georgia, there was a superb company called Seal-Jet. They were very innovative. They had CNC cutting lathes and mills that were specifically designed to cut rubbers and elastomers.

They saved my ass many times in the industry I worked in. I could get teflon/silicone based pneumatic cylinder rings for the Swedish printing presses I worked with...for about $195 for the CAD work and about $15 each for the first 10 seals....within a 24 hour period of time.
A bargain when you are looking at six weeks turn time and $1000 for complete new cylinders from Sweden.....but I digress Laughing

So....over the period of a year...this company made for me....front sway bar bushings of Urethane (years later I realized these do not live very long in urethane), new front suspension centering rings made of delrin, clutch slave seals from buna-N (they did not have EPR or EPDM in a hard enough durometer to cut cups)...so these seals lasted about a year each.....and I had them make cups of the same material for my brake pressure regulator.

The problems they had making seals on the CNC lathe is that at that point in time the rubber needed to be 75-80 durometer in order to be accurately cut.

The problem this makes...is that the factory seals made of EPDM...are about 45-55 durometer. So...installing the new, harder seals.....was VERY difficult. I ordered 10 seals for the regulator....and was only able to install three over three years without ripping them. I had to build a tapered mandrel out of plastic to be able to install them and had to heat them up in boiling water.

That company went out of business...or actually sold out its branches to other companies (it was a franchise).

So...today....there are hundreds of companies that can make seals like this. They have better technology now...sharper cutters, the ability to freeze rubber carefully to make it hard enough to cut or grind etc.

There are also short run injection molding companies that can injection mold this type of part of you have enough money (not that expensive but not cheap...you would have to do a batch run).

So why am I telling you this?

So way back when...when I could no longer get reliable seals for these units....and I needed a brake regulator...I abandoned ever working with these units again. I used to have about a dozen core units. Many in poor shape with bad rust because they were pulled from wrecks.
I went to a Hawk or Porterfield regulator on my four door and it seemed to be OK. That car got wrecked, stripped and scrapped....so I no longer have it.

In the pre-internet days I had no idea there were other cars that used these regulators.

I do consider this a necessary part...if you can get it.

So cut to now.....I have two cores...both in very bad shape. I can probably rebuild the cylinder but have only one piston that is broken.

So....last night I bought a core on E-bay for about $45. I have no idea of the internal condition. Fingers crossed...but if the piston is fine...between the three cylinder cores I will now have I should be able to buy a kit from PMB and put one together.

My suggestion is that if you have a 411/412 two or four door....next time the brakes are down for maintenance...pull and inspect yours.

If yours has been bypassed with a Tee...and you do not have one...look for a core. These will only get more rare.

Shortly I will be doing a complete rebuild thread to add to this.

This will include bench calibration. For the bench calibration you will need three short sections of metal brake line...you can probably do this just as well with brake hoses....a single circuit master cylinder from any car you want with a simple reservoir made from a brake fluid bottle....and two gauges that go to 600 psi from Mcmaster Carr.

If you like to do things yourself....about $25 for the pair of gauges...maybe $25 for brake lines...$23 for a single circuit beetle master cylinder from CIP 1. About $75-80 all told....not including paint etc....and $59 for the kit.

Thats about $165... Laughing

So...by the way the price that PMB lists...is about $169....and thats painted, zinc plated and calibrated. That price is excellent.

I plan to calibrate my own because I will also be putting in a Tee block both before and after the regulator with a bleeder valve in both that doubles as a gauge port....also since I will be converting to rear discs....its most probable that I will need to recalibrate my unit so It pays to have the tools and know how.

This is nice to have...because if there is a problem in the future with the unit....the surest way to test if the unit is working or not...is to install gauges both before and after the regulator...and have someone step on the brakes hard.

Also..I have found that when doing a total overhaul of anything like master cylinder or front calipers...when the system gets drained....air bubbles at the regulator can prevent fluid from getting to the rear wheel cylinders. Its nice to be able to bleed the line up to the regulator...and right after,

In the past I did this with an assistant by having them step on the brake while I cracked the fluid line at the regulator. I would install speed bleeders in them.

So look for good regulator cores if you do not have one.

This guy on ebay has three used ones

http://www.ebay.com/itm/OEM-Original-Factory-Porsc...mp;vxp=mtr

at $44...if the cylinder is not just crusty rusted....they would be good rebuild candidates.

Stay tuned! Ray
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PostPosted: Sun Mar 05, 2017 5:29 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

The core I just removed from my four door looks good on the out side. The original paint finish still shines. As mentioned previously I managed to install a "T" connection in it's place.

There has been off an on problems with the braking on the right wheel. It would lock-up but loose enough to drive(like pulling a heavy loaded trailer). It would release about ten minutes after parking. All the usual steps to find the problem have been taken, but the problem still exists is why I'm finally considering the regulator as the possible problem. Now that it has been removed and a T installed I can drive the car, to test for the problem. I mentioned earlier that I broke the bleed valve on the left wheel, and I picked up a new cylinder from Bughaus in Tulsa yesterday. I'm anxious to get it installed, bleed the brakes, and start driving the car---and see what happens.

The core has no rust, and looks great on the outside. It should be a good candidate for rebuild.
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PostPosted: Sun Mar 05, 2017 10:51 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

titan3c wrote:
The core I just removed from my four door looks good on the out side. The original paint finish still shines. As mentioned previously I managed to install a "T" connection in it's place.

There has been off an on problems with the braking on the right wheel. It would lock-up but loose enough to drive(like pulling a heavy loaded trailer). It would release about ten minutes after parking. All the usual steps to find the problem have been taken, but the problem still exists is why I'm finally considering the regulator as the possible problem. Now that it has been removed and a T installed I can drive the car, to test for the problem. I mentioned earlier that I broke the bleed valve on the left wheel, and I picked up a new cylinder from Bughaus in Tulsa yesterday. I'm anxious to get it installed, bleed the brakes, and start driving the car---and see what happens.

The core has no rust, and looks great on the outside. It should be a good candidate for rebuild.


I would replace both wheel cylinders at one time. Same age.....dont yo through this twice.

Also....the problem you are noting.....can be caused by a defective wheel cylinder, the brake pressure regulator....and even more commonly......a brake hose welling up on the inside.

If the brake hoses have not been replaced within the last 7-8 years.....I would replace those too. They are usually cheaper or as cheap as the wheel cylinders. Ray
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PostPosted: Sun Mar 05, 2017 1:07 pm    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

The brake hoses are all new, and new cylinders were installed 2 years ago. I do plan to replace both cylinders as you suggested just to be sure. The cylinder on the wheel I'm having trouble with has been in my mind and as you suggested a possible cause of the problem. If removing the regulator, and installing a T and replacing the cylinders results in no more problem then it must have been the regulator. It will be interesting to see what happens.

A point that supports the regulator being the problem is the amount of brake pressure when it locks up. As I mentioned before it was just enough pressure you couldn't move the car by hand, but move it with the engine. That means possibly the brake pressure was just enough to prevent a lock up of the brake while the car was in motion, which is what the regulator does. But for some reason it wasn't releasing on the right rear.
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PostPosted: Sun Mar 05, 2017 1:34 pm    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

titan3c wrote:
The brake hoses are all new, and new cylinders were installed 2 years ago. I do plan to replace both cylinders as you suggested just to be sure. The cylinder on the wheel I'm having trouble with has been in my mind and as you suggested a possible cause of the problem. If removing the regulator, and installing a T and replacing the cylinders results in no more problem then it must have been the regulator. It will be interesting to see what happens.

A point that supports the regulator being the problem is the amount of brake pressure when it locks up. As I mentioned before it was just enough pressure you couldn't move the car by hand, but move it with the engine. That means possibly the brake pressure was just enough to prevent a lock up of the brake while the car was in motion, which is what the regulator does. But for some reason it wasn't releasing on the right rear.


Yes. If you look at the parts and seals in the regulator you can see what happens.

Usually its either the piston getting sticky in the bore due to the o-ring....and not the sealing cup.....or the nylon pintle being gummed up. Either way it can partially block one port. Ray
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PostPosted: Mon Mar 06, 2017 7:14 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

Just to make a comment for a food for thought caution as to whether or not a regulator is needed. I'll tell you about an experience I had.

I live on a side road just off of a modestly traveled state highway which means when I'm approaching my turn off the highway I'm travelling at highway speed 60 to 65 MPH. Several years ago, before I knew what that regulator in the brake system was there for, I was approaching my turn off, and flipped my turn signal on to let following traffic know I would be slowing for a turn. Just about a hundred feet before my turn, there was sand on the highway(perhaps spilled by a truck making the same turn). My front brakes locked up and skidded, and I was able to control my skid off to the shoulder, and right past my turn point. My rear brakes did not lock, and I thought there was a problem with my rear brakes, but of course I have learned later thru this forum that the regulator was doing it's job. If it hadn't been for the regulator the rear brakes would have locked and the car could have swung to the left into oncoming traffic, and who knows what after that.

Ray has mentioned a similar experience also. It just makes you think about it more seriously. It would take just one incident to wipe out your car and perhaps you with it.
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raygreenwood
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PostPosted: Fri Mar 17, 2017 2:45 pm    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

A little update....since I just got a good core in the mail yesterday. Since this is from a 914 instead of a 411/412...thought I would point out the difference and since it has a complete piston I thought I would show that.

Image may have been reduced in size. Click image to view fullscreen.


First on the right you can see what an unbroken piston should look like with its complete tail.

The one on the left is from a 411/412. It has a single fluid inlet from the MC and a separate outlet for both rear brakes.

The 914 specific one is on the right. It uses the same fluid inlet as the 411/412. But... note the un-drilled fluid passage and the use of a Tee that splits off from the single fluid outlet to the rear brakes.

So if you acquire a 914 specific unit for a rebuildable core...be ready to do one of three things:

1. Either swap in the cylinder body from a 411/412 if you have one. It bolts right up and changes nothing internally.

2. Drill and tap the fluid port so you can use your existing metal brake line set up without changes.

3. Just use the 914 version and reroute your metal brake lines.

The rest of the information about stripping this unit down will be posted in this thread
https://www.thesamba.com/vw/forum/viewtopic.php?t=674249

since its mostly about plating and corrosion. Ray
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raygreenwood
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PostPosted: Sat Mar 18, 2017 11:40 am    Post subject: Re: 411-412 rear brake pressure regulator Reply with quote

As an update of information to the above post....A seller called "914ecology" on E-bay who knows his 914's better than I do for little production details...I have this information:

Quote:
For 914 specific brake proportioning valves:

Early style (pre vin 47442915751) brake proportioning valve.

Brief lesson on brake proportion valves:

Early pressure regulators had a fluid inlet at the bottom and a fluid outlet at the top. A single inlet was fine but, the outlet now needed to go to the left and the right sides of the car. A brass "T" fitting with a banjo bolt was employed to do the job.

The valve had always been bossed for multiple outlets but, only the one at the top had been tapped to 10x1.

Later pressure regulators were simply tapped on the top "and" now the back side facing the firewall. The right side line went into the back and the left side went directly into the top.

SO.........If your pressure regulator is missing you can tell by the VIN or, by your lines. Early ones have straight line ends that go directly into the T. Later ones have 90 degree bends at the end of the lines.


So there are some 914 proportioning valves that do have the two outlets.

My advice on buying a rebuildable core if you do not have a proportioning valve on your car (like the wagons/variants)...or if yours is just beyond repair so you dont have a core...or the PO has replaced it with a Tee fitting...so you dont have a core........do not get hung up by waiting and shopping around for one that that has the two outlets.

Buy one when you find it and its reasonable in cost.

These things do not grow on trees. In the big scheme of things....not a very large number of production cars used these parts....just 411, 412 and 914 for these exact castings.....and only BMW 2002 and 3.0 CSI used the same cast iron valve body with a different spring chamber. Probably one of the last models that used a similar valve that looks about 40% different but can most probably be installed and adjusted with some work...was the BMW 320i.

They look like this.
http://www.ebay.com/itm/BMW-320i-Ate-Brake-Proport...mp;vxp=mtr

You can see that the valve body is the same or very similar. Different build out on the spring section.

There are not huge herds of these cars on the road or even in the junkyards anymore. So if you need a core...buy one even if its different in its outlet lines.

For this part on your two or four door car....its would be a small and simple price to pay to have to bend up an extra metal brake line. Ray
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