E90 Brakes Spongy

[AshJ]

Hi all, need some help please,
My 2007 e90 320i , brake pedal just became spongy, ohk, not sure if thats the best way to describe it,. pedal is just gone very low when pressing, brakes still hold, but its not how it used to be, if I tap on the pedal and then press it almost seems to come back up to its normal position,
we do not have a BMW dealership in my town, we have a few ex BMW techs who own private workshops, have had them look at the car, but they cannot give me a definate cause and fix, techs have said they looked for brake fliud sweating and leaks , none visible, even monitored the fiuld level, thinking maybe there is a leak we cannot see, but nothing,

Would really appreciated advise,

Ta
Ash

 

[freakoid9000]

At a guess from how you've explained it, I would say its your brake master cylinder.

 

[AshJ]

At a guess from how you've explained it, I would say its your brake master cylinder.

Hi ,
thank you for the suggestion,
cant see visible sweating, do you think maybe seals internally are leaking/bypassing?

 

[Blue Shirt]

First step would be to flush the brake fluid, which needs to be done every two years at a minimum. If the spongy pedal feel persists, it could be a leaky seal inside the master cylinder.

 

[AshJ]

First step would be to flush the brake fluid, which needs to be done every two years at a minimum. If the spongy pedal feel persists, it could be a leaky seal inside the master cylinder.

Hi , ironically, asked a VW /Audi tech, and he was the only one who suggested a fluid flush 1st and then take it further,
Thank you

 

[Solo Man]

I think that the brake fluid flush is the answer as this is probably the most neglected item on a car that people tend not to think about doing. Have flushed some brakes that look like coke came out of the flush!

 

[AshJ]

I think that the brake fluid flush is the answer as this is probably the most neglected item on a car that people tend not to think about doing. Have flushed some brakes that look like coke came out of the flush!

Hi
Wow, well, I opened the filler bottle and the brake fluid looks like old engine oil, very thick and brown
Thanks for the advice will get the fluid changed and report back

 

[AshJ]

Good Morning,
Ohk , update on spongy brake pedal, we did the fluid flush over weekend, it came out a redish colour, pedal much better , but still does feel as sensitive and high as it used to be , any suggestions on the whether to get the OE master cylinder from BMW or other?

 

[Gordvisr]

Give it a few days and flush again.

 

[AshJ]

Hi All,
Quick update on brake issue, a week after flush tech did what he referred to as a pressure bleed, apparently its done by activating the ABS pump via diag tool, this did not make much difference, so we got in a recon master cylinder, made a huge difference , but pedal still not responsive as it used to be, so tech wants to try the pressure bleed again.

 

[AshJ]

Hi guys , apologies for posting after a long while,
Just an update on the spongy brake issue, ended up getting a seal kit for the vacuum pump, removed with much patience , seemed like easier to pull engine out and work on the vac pump, but it worked out fine , brakes perfect again

Thank you for all the advise

 

[Mytfine]

Hi guys , apologies for posting after a long while,
Just an update on the spongy brake issue, ended up getting a seal kit for the vacuum pump, removed with much patience , seemed like easier to pull engine out and work on the vac pump, but it worked out fine , brakes perfect again

Thank you for all the advise

Remember to change your fluid every 2 years.

 

[Solo Man]

Thanks for reporting back. Good to know you came right and what the cause was!