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.