Hard Brake Pedal

[Ramzi]

HI Guys

I was on a mountain drive yesterday with some fellow Ms and on the way down i was having problems with my brake pedal being too hard. if i push it hard enough the car does brake well but i have to put a lot of physical effort into it especially going down fast into a tight corner. My oil level is good and pads and disks are still very good also. any idea how to make it lighter?

[Bruno]

Wirelessly posted (BlackBerry9000/5.0.0.509 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/179)

Bleed it

[Shak]

HI Guys

I was on a mountain drive yesterday with some fellow Ms and on the way down i was having problems with my brake pedal being too hard. if i push it hard enough the car does brake well but i have to put a lot of physical effort into it especially going down fast into a tight corner. My oil level is good and pads and disks are still very good also. any idea how to make it lighter?

Hi,
It seams like you have lost your brake assist from the brake servo?

Cause 1 , brake booster servo unit diaphragm leaking internaly(new servo and brake master cylinder)

Cause 2 , Vacume pipe from the inlet manifold to the brake servo leaking,

[Ayham]

He'd need to bleed if the pedal was "mushy" ===> air bubbles in the system.

A very stiff pedal feel resembles pressing the pedal on a car that's been parked for a while. The common thing between the two cases is the lack of vaccum pressure.

[Ramzi]

Hi,
It seams like you have lost your brake assist from the brake servo?

Cause 1 , brake booster servo unit diaphragm leaking internaly(new servo and brake master cylinder)

Cause 2 , Vacume pipe from the inlet manifold to the brake servo leaking,

In both cases, shouldn't the oil level go down? In my case its fine!

[Ramzi]

He'd need to bleed if the pedal was "mushy" ===> air bubbles in the system.

A very stiff pedal feel resembles pressing the pedal on a car that's been parked for a while. The common thing between the two cases is the lack of vaccum pressure.

exactly, its just stiff whenever u depress it enough to actually start braking....it never really bothered me until yesterday since i was driving fast down hill for 20 minutes going hard on the brakes.

whats the fixing Reco?

[Ayham]

Wirelessly posted (BlackBerry8520/4.6.1.272 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/212)

The leak is a vaccum leak, not an oil leak.

Check your air hoses throughly, worth spending time doing this. Any rough idling?

[Ramzi]

Wirelessly posted (BlackBerry8520/4.6.1.272 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/212)

The leak is a vaccum leak, not an oil leak.

Check your air hoses throughly, worth spending time doing this. Any rough idling?

Not really, it idles very smooth and normal....

[Shak]

In both cases, shouldn't the oil level go down? In my case its fine!

Only a few drops from the master cylinder over a period of time can contaminate the servo diaphragm causing leaks and loss of vacume thus causing hard brake peddle.

An air leak from the Vacume side of things should give you some indication of a slight missfire! but not allways the case !

But if the brakes are spoongy and after pumping they are fine its a matter of bleeding !!!!!!!!!!

Lets see what the rest of the club say ?

[Ramzi]

so i should first start by bleeding the brakes and c if the problem persists?

thanks Guys for the feedback

Hi,
It seams like you have lost your brake assist from the brake servo?

Cause 1 , brake booster servo unit diaphragm leaking internaly(new servo and brake master cylinder)

Cause 2 , Vacume pipe from the inlet manifold to the brake servo leaking,

In both cases, shouldn't the oil level go down? In my case its fine!

The two points specified seemed to fit right to a t. If after bleeding the brake pedals are hard to push, what would be the likely cause and resolution? Bled twice = same thing.

[SewerSideUp]

My pedals gets a little stiff after hard braking on downhill roads as well then when the oil and pads get hot it's start to mush out a little bit, that's when I ease off. But, I have my intake system/vacuum hoses/manifold/PCV and lines/ICV and lines completely sealed with not air leaks and it still happens. I was in slow moving traffic once, the car infront of me braked instantly, I braked, the pedal moved forward and then stiffened. Because of the short time I didn't stop early enough and bumped into him.

Booster diaphragm ? Is it rebuildable ? My dad's got a 75' Range Rover and we rebuilt the booster on that, changed out the diaphragm and spring. Possible on the E36 ?

[Shak]

My pedals gets a little stiff after hard braking on downhill roads as well then when the oil and pads get hot it's start to mush out a little bit, that's when I ease off. But, I have my intake system/vacuum hoses/manifold/PCV and lines/ICV and lines completely sealed with not air leaks and it still happens. I was in slow moving traffic once, the car infront of me braked instantly, I braked, the pedal moved forward and then stiffened. Because of the short time I didn't stop early enough and bumped into him.

Booster diaphragm ? Is it rebuildable ? My dad's got a 75' Range Rover and we rebuilt the booster on that, changed out the diaphragm and spring. Possible on the E36 ?

Hi mate,
The booster is a sealed unit so it has to bo replaced! But you will not know until you remove the master cylinder to see what extent the damage is!

why it gets stiffer when u press the pedal in a continuous pumping action?

i mean pressing and releasing repeatedly...

cos it gets hot or what?

[Shak]

why it gets stiffer when u press the pedal in a continuous pumping action?

i mean pressing and releasing repeatedly...

cos it gets hot or what?

If the servo diaphragm is leaking it will only work the first time you apply the brake,there after it will take longer for the vacume to build up again and thus have no brake assist straight away!

Make sense or not !!!