325ci e46

opposer · 04-05-2024, 01:48 PM

Hi.
I tried to drift my e46 (it has a locking diff and a manual)

After being spun, the brake pedal becomes absolutely soft - falls to the floor and the car doesn't brake. If you press it one more time - it becomes firm again like always.

I disabled totally the DSC (holding DSC button for 5secs).

What can be the problem? Maybe I should take out the ABS fuse before drift training?

The brake fluid is fresh and level is ok.

tracer bullet · 04-05-2024, 02:04 PM

I like the line of electronic thinking, but - is there a chance your brake fluid level is low and you momentarily slosh the fluid up to the side and let some air in? I wouldn't think it'd suddenly purge back out right afterwards so probably not, but - maybe check the level?

cbpip · 04-05-2024, 11:06 PM

Could be pad knock back.

M3SQRD · 04-06-2024, 03:05 PM

I agree. It sounds like the brake piston(s) are getting pulled back off of the pads and into the caliper while drifting. Getting the pedal back after pumping/bumping the brake pedal once and then works properly again. There’s not much you can do with stock calipers. The usual solution is to install 6 lbf/in anti-knock-back springs behind each piston.

04-05-2024, 01:48 PM	#1
opposer Enlisted Member 15 Rep 35 Posts Drives: Subaru STI EDM 2005 Join Date: Jun 2017 Location: Moscow, Russia iTrader: (0)	325ci e46 - Brake pedal to the floor after spinning Hi. I tried to drift my e46 (it has a locking diff and a manual) After being spun, the brake pedal becomes absolutely soft - falls to the floor and the car doesn't brake. If you press it one more time - it becomes firm again like always. I disabled totally the DSC (holding DSC button for 5secs). What can be the problem? Maybe I should take out the ABS fuse before drift training? The brake fluid is fresh and level is ok.
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04-05-2024, 02:04 PM	#2
tracer bullet Brigadier General 3917 Rep 4,370 Posts Drives: '25 Z4, '15 X3 35i (135i sold) Join Date: May 2011 Location: Saint Paul, MN iTrader: (1)	I like the line of electronic thinking, but - is there a chance your brake fluid level is low and you momentarily slosh the fluid up to the side and let some air in? I wouldn't think it'd suddenly purge back out right afterwards so probably not, but - maybe check the level?
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04-05-2024, 11:06 PM	#3
cbpip Second Lieutenant 264 Rep 275 Posts Drives: BMW Z4C 3.0si 3 pedal Join Date: Nov 2020 Location: MD iTrader: (0) Garage List 2007 BMW E86C [10.00]	Could be pad knock back.
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04-06-2024, 03:05 PM	#4
M3SQRD Major General 4127 Rep 7,690 Posts Drives: G20 330ix,F22 240iX,e92 M3 Join Date: Jun 2009 Location: Mid-Atlantic iTrader: (12)	I agree. It sounds like the brake piston(s) are getting pulled back off of the pads and into the caliper while drifting. Getting the pedal back after pumping/bumping the brake pedal once and then works properly again. There’s not much you can do with stock calipers. The usual solution is to install 6 lbf/in anti-knock-back springs behind each piston.
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