Rear brake pressure regulating valve Rebuild

[Barry.b]

Hi guys
I just rebuilt my rear brake pressure regulator valve.

I used a pmb kit that is meant for an early Porsche.
Anyway I took mine off and cleaned it and glass bead blasted it before I took it apart.
It was easier to keep the blast media out that way .
It is spring loaded so I put it in a hydraulic press so that I could hold it while I removed the 4 m6 screws holding it together.
Once I had the screws out , I slowly released the hydraulic press to let the spring pressure off.
It separated by about 20 mm then the spring was free.
I took all of the internals out and cleaned them.
There is a type of sliding piston which has 2 seals on it , 1 o-ring and 1 radial seal.
They need replacing, the o-ring is easy.
The radial seal is difficult to do.
The kit comes with a tapered tool which you put onto the end of your piston , then you have to push the new seal up the taper and onto the shaft until it pops into its groove.
I used hot water to make the seal softer and I used lubricant to help also.
It was not easy !!!
Note the tapered tool in the Porsche kit was too short for the Bmw part which left a reduced diameter with a step ahead of it on the shaft , a kind of “ trough “so I made up the difference by wrapping masking tape around and around the shaft until it was the same diameter as the tool and the shaft , I didn’t want the seal to fall into the “ trough “.
Once that was done I was able to slide the seal up the the taper , over the masking tape and on into its groove on the shaft.
Then when all of the seals and o-rings are replaced, and greased up , you use the 4 new screws to put it back together. The screws are longer than the originals so they are long enough to pull the spring down so you don’t need to use a press.
I hope that might be of some help, if others are planning on rebuilding theirs.

 

[deQuincey]

I had to check it in my own DIY

Lan-brakes rear brake valve renew

this started some time ago with the dissasembly of this spare that i bought the rear proportional brake valve as it was advised use a tool to retain the spring when removing the bolts i will renew it following the advice of a forum friend

e9coupe.com

what is the use of the grease bag in the kit ?

 

[Barry.b]

I had to check it in my own DIY

Lan-brakes rear brake valve renew

this started some time ago with the dissasembly of this spare that i bought the rear proportional brake valve as it was advised use a tool to retain the spring when removing the bolts i will renew it following the advice of a forum friend

e9coupe.com

what is the use of the grease bag in the kit ?

Hi there
I like your version of the same job !
The grease is used to lubricate the bores on the valve.
To be honest I only use a Tiny amount. , I don’t want any of it to become loose as I think it could flow off somewhere with the brake fluid and cause some problems elsewhere in the system. ( perhaps )

 

[jefflit]

Mine was similar. Fortunately, I didn't have to sandblast the entire thing to clean it up. Thus, the original finish on the canister w/ green sealant around the adjuster remained. Replated the mounting bracket and bolts.

 

[deQuincey]

Hi there
I like your version of the same job !
The grease is used to lubricate the bores on the valve.
To be honest I only use a Tiny amount. , I don’t want any of it to become loose as I think it could flow off somewhere with the brake fluid and cause some problems elsewhere in the system. ( perhaps )

ok, so then that is brake grease, as ATE brand has
thanks

 

[Christopher]

Hi guys
I just rebuilt my rear brake pressure regulator valve.

I used a pmb kit that is meant for an early Porsche.
Anyway I took mine off and cleaned it and glass bead blasted it before I took it apart.
It was easier to keep the blast media out that way .
It is spring loaded so I put it in a hydraulic press so that I could hold it while I removed the 4 m6 screws holding it together.
Once I had the screws out , I slowly released the hydraulic press to let the spring pressure off.
It separated by about 20 mm then the spring was free.
I took all of the internals out and cleaned them.
There is a type of sliding piston which has 2 seals on it , 1 o-ring and 1 radial seal.
They need replacing, the o-ring is easy.
The radial seal is difficult to do.
The kit comes with a tapered tool which you put onto the end of your piston , then you have to push the new seal up the taper and onto the shaft until it pops into its groove.
I use hot water to make the seal softer and I used lubricant to help also.
It was not easy !!!
Note the tapered tool in the Porsche kit was too short for the Bmw part which left a reduced diameter with a step ahead of it on the shaft , a kind of “ trough “so I made up the difference by wrapping masking tape around and around the shaft until it was the same diameter as the tool and the shaft , I didn’t want the seal to fall into the “ trough “.
Once that was done I was able to slide the seal up the the taper , over the masking tape and on into its groove on the shaft.
Then when all of the seals and o-rings are replaced, and greased up , you use the 4 new screws to put it back together. The screws are longer than the originals so they are long enough to pull the spring down so you don’t need to use a press.
I hope that might be of some help, if others are planning on rebuilding theirs.

Thanks Barry - most informative.
I'll follow your instructions on a spare unit i have

 

[Fritzie]

Hi guys
I just rebuilt my rear brake pressure regulator valve.

I used a pmb kit that is meant for an early Porsche.
Anyway I took mine off and cleaned it and glass bead blasted it before I took it apart.
It was easier to keep the blast media out that way .
It is spring loaded so I put it in a hydraulic press so that I could hold it while I removed the 4 m6 screws holding it together.
Once I had the screws out , I slowly released the hydraulic press to let the spring pressure off.
It separated by about 20 mm then the spring was free.
I took all of the internals out and cleaned them.
There is a type of sliding piston which has 2 seals on it , 1 o-ring and 1 radial seal.
They need replacing, the o-ring is easy.
The radial seal is difficult to do.
The kit comes with a tapered tool which you put onto the end of your piston , then you have to push the new seal up the taper and onto the shaft until it pops into its groove.
I used hot water to make the seal softer and I used lubricant to help also.
It was not easy !!!
Note the tapered tool in the Porsche kit was too short for the Bmw part which left a reduced diameter with a step ahead of it on the shaft , a kind of “ trough “so I made up the difference by wrapping masking tape around and around the shaft until it was the same diameter as the tool and the shaft , I didn’t want the seal to fall into the “ trough “.
Once that was done I was able to slide the seal up the the taper , over the masking tape and on into its groove on the shaft.
Then when all of the seals and o-rings are replaced, and greased up , you use the 4 new screws to put it back together. The screws are longer than the originals so they are long enough to pull the spring down so you don’t need to use a press.
I hope that might be of some help, if others are planning on rebuilding theirs.

Hello Barry,
Thanks for your writing. Very helpful!
Fritzie

 

[Fritzie]

Hello e9 Freunden,
Just refurbished the pressure regulator valve. Used the PBM kit. The special tool which goes with the kit is very useful but too short for the e9 (the kit is normally used for Porsche 914). So I bought two kits and used one of the special tools to extend the other one. I welded a part of it together ( I don’t have a lathe otherwise that would be the best way).
I used a very little of the red grease. Don’t believe more it’s better.

 

[Lean181]

Hi everyone, I hope you're all doing well!

I've been reading this and other threads related to the brake pressure regulator because I'm experiencing some problems with it.

In my case, I'm rebuilding an E3 that was sitting for a long time, and I've taken the time to rebuild several brake-related parts, such as the calipers, brake master cylinder, brake booster, etc.
The problem arose when I started bleeding the rear brakes and couldn't get any fluid to reach the rear calipers. Upon closer inspection, I found this regulator and noticed that fluid pressure was reaching its inlet, but it wasn't flowing.
I removed it from the car and disassembled it to clean it. I found a lot of dirt, but even after cleaning it, I couldn't get the fluid to flow.

Reading an Ate operating manual for this regulator, I discovered that the internal holes of the valve are clogged, and the fluid isn't flowing correctly inside.

I wanted to ask if you know of any replacement kit or regulator that includes the internal valve, since the replacement kits I've seen include gaskets and seals but not the valve housing.

PS: I'm not sure if it's appropriate to post my question here or start a new thread; I apologize if I didn't post it correctly.

Regards, Lean

 

[boonies]

I have a kit and plan to take mine apart when I re-furbish the rear axle so no direct experience yet with the valve. Since it sounds as though you have had the valve apart, have you considered using an ultrasonic cleaner to soak the the dis-assembled valve to dislodge the debris inside the valve itself?

PMB Performance specializes in Porsche parts and service and they also rebuild these. You can find some resources and diagrams here.

 

[mulberryworks]

That's nice information from PMB but the kit seems to be NLA from everyone. PMB used to sell it but must be holding onto their remaining supply so they can offer a rebuild service for these brake pressure regulators while the parts last.

 

[e9Leveque]

I assume when you say the kit is NLA you mean a kit with the actual valve? They still do offer the gasket and seals kit on their website - just ordered one since I had taken off this part last week and cleaned it externally but hadn't refreshed its internals, figure before I refill and bleed the braking system would be the time!

Pressure Regulator Repair Kit

You've searched the world over and you've discovered that this is the only 914 "Pressure Regulator Repair Kit" on the planet. Well... you have finally landed. It's a pressure regulator, "NOT" a proportioning valve. It proportions "NADA". It is the first anti-lock brake device ever to be...

pmbperformance.com

Their website also has the following text as a very nice write-up. Interesting that there is some epoxy underneath that nut, I guess that's serving as a loctite equivalent

Rebuilding the regulator at home.

If you're a DIYer, you're in luck as well, we offer a full rebuild kit including the proprietary conical tool that makes getting some of the tricker O-rings into the body a breeze. The rebuild kit can be found here

To rebuild the regulator correctly, follow the following steps:

• Remove the pressure regulator from your car. You'll find it mounted on the firewall.
• Completely disassemble the regulator being sure to keep all the hard parts not included in the rebuild kit safe for reuse.
• Remove all old seals on the valve, be careful not to mar the seating surface during removal.
• Lube the installation cone with a silicon brake lubricant. This will allow the seals to easily slide onto the valve body.
• Place the seals onto the shaft, skirt facing down. Use a pick to stretch the seal, and "hula hoop" the seal down into the proper journal on the valve body.
• Put the remaining small O-ring on top of the valve in the smallest journal. Lightly lubricate the valve and place it into the body of the pressure regulator.
  
  
• Place the large o-ring on the 32mm hex cap. Screw the cap back onto the regulator valve body.
• Place the body of the regulator in a vise, and use a 32mm wrench to tighten the cap as tight as you can.
• Turn the valve body upside down and install the gasket.
• Place tall hat on the bottom of the valve body. Add spring. Add short hat upside down into spring (surface is cupped inwards to the spring).
• Assemble the 17mm nut on the adjuster screw, and adjust the nut accordingly.
• Screw the assembly into the spring housing leaving space for epoxy and final adjustment.
• Mix and lay epoxy underneath the nut. Screw the nut on, and re check that your adjuster nut is still correctly positioned.
• Place the spring housing onto the valve body.
• Install the mounting bracket, making sure the bracket is positioned correctly.
• Place new screws and lock washers through the mounting bracket and spring housing.
• Using a press, press the spring housing into the valve body. Make sure all components stay in alignment as the housing mates to the body.
• Gently thread the screws into the valve body
• Remove from press, and torque all screws down to 15ftlbs.