Stiff Brake pedal

[ryanhouston_e46]

Hi all.

Driving along normally the other day and suddenly the brake pedal goes stiff and i'm having difficulty stopping the car at low speeds. Brakes fine from high speeds. One week ago the brake pads warning light came on. I replaced the front and rear pads and the light went off. Bleeding procedures were carried out by a BMW mechanic. Is there any way to fault find this problem? I read on some international forums that it may be the brake booster, vacuum pipe with built in check valve or vacuum pump itself.

I'm driving a 2003 e46 318i f/l. N42 B20A motor.

Thanks in advance for any responses.

 

[zaleonardz]

The stiffness does indicate that your vacuum assisted booster went poof, or it could very easily be a vacuum line.

The fact that the pedal is stiff indicates that you have a closed hydraulic circuit, which means its fine from the master side onwards.

Def booster/vacuum related...

H31 braking system FTW

 

[xcalibur]

Could be any one of those things.

This "tutorial" might help you find the problem if you prefer DIY.

http://www.ehow.com/how-does_4829365_testing-procedure-brake-boosters.html

 

[@jukesnc]

Hi gents i have a e46 318 i 2001facelift auto i just want to make sure im not crazy but can my brake booster cause my car to smoke if the brakes were applied hard ? This problem is getting worse also pedal is hard for emergency braking its dangerous but i adjusted to the braking its this smoke which doesnt smell like oil at all it smells likr break fluid ? Please help ?:thumbdo:

 

[Iceman007]

Its your Vacuum pump thats gone

 

[@jukesnc]

Hi thanx for your reply im not so clued up so which vacuum pump is it ? Isit the oil separator or the brake booster or where does this vacuum pump sit ? [/align]

 

[GPGrobler]

It is the pipe that goes from the brake booster to the engine.

 

[Iceman007]

Vacuum pump sits on the back of the head