MixMasterMIke

I have a 2006 530xi and I have a problem with my brakes I just can't figure out.

Symptoms:
Long Brake Pedal Travel - Basically goes all the way to the floor
High effort to slow down the car
Doesn't feel firm

What I tried to fix it:
Replaced master cylinder
Flushed the fluid using Motiv bleeder and super blue fluid.

Could there be air in the abs unit? Is there a way to cycle it without using a DIS that can be done on other models. I have DTC but I don't think I have DSC. The brake booster tests you can do with the pedal and turning the car on and off seem to show that it is working find but the pedal is pretty much to the floor when i do it. Any ideas?

DanL

Assuming you don't have a leak somewhere and you're sure you've bled the master cylinder correctly, it does sound like you have air in the ABS unit and yes, you normally need to use DIS or INPA to bleed it. I'm not sure if this will work or not, but since you're in Buffalo, perhaps you can use a slick parking lot to your advantage. Perhaps if you can engage the ABS a lot it will drive the air out of the unit so that you bleed it out at the calipers. After all, that's what DIS does -- it rapidly pulsates the ABS unit to force any trapped air out and into the lines so that it can be removed through the normal bleeding process.

twh

High effort to stop is often a faulty brake vacuum booster. Basically, the car is behaving like an old time car without power brakes.

So, you should check the vacuum lines to the brake booster.

Also, the N52 has an auxiliary vacuum pump rather than taking the vacuum from the intake manifold. The Bentley manual says it is located front lower left of the engine and is driven off the oil pump chain.

Check that also to make sure the vacuum hoses are hooked up and check for a vacuum.