What is this ?

[spbt1]

I am about to replace my brake master cylinder and have noticed that the two brake pipes out of the master cylinder go into a smaller cylinder just underneath and then from that to the abs pump. Can someone tell me what the smaller cylinder is as it coesn't show on realoem's parts listing.

I would like to replace that aswell but don't know what it is for, i am presuming it is some sort of balancing cylinder but i really don't know so am unable to order.

[spbt1]

So i have been to bmw and we have looked it up on their system and it appears to ba a brake pressure regulator. Although the picture on their system is different.

Does anyone know if this is a must as i have never come accross one before. Plus they are £113.00 from bmw.

[DanThe]

Delete your other thread, no need to have two running.
What master cylinder have you now got to fit? Same as the one you took off or a later one?

[spbt1]

i have now found that this is the brake pressure regulator of which two types were manufactured. I have the earlier one although both give the same results.

Can anyone tell me if they have done away with theirs and what the effects were (locking up the rear end )

I have purchased a new Brake master cylinder but the brake pressure regulator appears to be a dealer part and is £113.00.

I am going to fit the MC and hopefully the pressure regulator is functioning ok as the problem i have is not getting fluid to the rear calipers. Fronts bleed up fine.

[spbt1]

Hi Dan yes i have a purchased one from gsf that is a match for the one i have taken off. What are your thoughts.

[DanThe]

If you have the same master you will have to refit the regulator. With a later master cylinder you wont need the regulator

[spbt1]

Cheers for that DanThe, would you recommend changing to the later one. If so which model i.e 1990 325i ?

[DanThe]

Ignore what I said, its rubbish

Had a closer look today at a car im working on which had the same split system crap yours has, im changing the servo and binning the ABS, this car had no pressure regulator in the usual place which is down by the fuel lines in the engine bay, it had a straight through piece instead. Im assuming this is because the pressure regulator is part of the split system thing mounted on the servo. If you get rid of this you will have to fit a later one by the fuel lines IMO, I stripped a late regulator down and it just looks like it prevents the rear brakes coming on when braking lightly, normal/heavy braking and the rears will work. Will add some pics in a mo

[DanThe]

Here are some pics of the straight through piece, modelled by the lovely Kelly 19 from Daventry





And this is the pressure regulator

[Rav335uk]

Nice pics Dan

[spbt1]

right thanks for that Dan i'm not going to get much chance to work on it this weekend as i am in Daventry...............

[DanThe]

bump