Changed brake pads...now very soft pedal

[jonfarrell]

Newbie here but long time BMW owner, thanks for allowing me to join the discussion group. Removed tire, removed caliper, installed new OEM pads on front, reinstalled caliper, reinstalled wheel. Now very soft brakes and significantly less stopping power. Brake fluid is fine, I bled the brakes on both sides of front, nothing but brake fluid coming out the bleeder. Any ideas? Some say the ABS unit must be bled, how the h*ll did air suddenly get in the ABS system, the hydraulic system was never compromised at all. The cap on brake reservoir was on all the time. Damn German car (JK I love it). Any ideas?

[jonfarrell]

Also, when the car is off, the brake pedal pumps up really hard, then when the car starts, the brakes go immediately soft and all the way to the floor. Before I changed the pads, everything in the braking system functioned 100%. This is so puzzling....

[Riche3]

With engine off ,if you pump the brake pedal ....it will exhaust the brake servo of any vacuum .

When fitting new brakes , the efficiency will be less ...until they are bedded in which can take up to 400 miles .
So no harsh braking during this period .

I would advise that you get some one who is qualified to look over your braking system to check if it is okay to be used for public highways ,

as if it has brakes fitted incorrectly it could dangerous to use .

[thestimp]

Dont need to bleed brakes for pad change. Sounds like shitty pads, or ABS issue. Time to hit the indy shop!

[LevinBR]

Did you only install new pads? Pads wear down the rotor over time and create a thumbprint on the rotor (wear pattern) which is unique to the pad. New pads will not have the same fit subtleties as the old and hence you will have less contact area and braking power. It'd be like trying to put your foot in someone else's footprint..

You should always replace pads and rotors together, but if you don't, there are a couple options; Over time, your new pads will "seat" to the rotor shape and braking will improve, but it may take a while. Another option (if you don't want to replace rotors) is to have your rotors re-surfaced. This is also refereed to as "cutting rotors" and will be done with a brake lathe. This, however, requires that there is decent life left in the rotors.

I have friend in the industry that takes it to another level. He says that even when the rotors and pads are replaced together and are brand new, the rotors should still be cut true to the hub with a brake lathe. This ensures peak performance, but is not entirely necessary in my opinion.

[Roch M4]

I replaced both pads and rotors on my X1 and I didn't have any issue. did you take off the extra brake fluid when you installed the new pads? There's a maximum fluid level (and minimum of course)..so when you push back the pistons, the level of the brake fluid goes up, then you need to take out with a syringe

[Mtpisgah]

Whenever I have changed my pads and rotors, they feel soft until the pads are properly bedded in. Bed them and go.