Strange EPB behaviour....

Lee S · #1 8th November 2013, 08:18 AM

Took the car for a service to Audi the other day and they said the brake fluid needed changing so I instructed them to carry on.

Got the car back and all was well, until I pulled up at some lights and engaged the parking brake. The motors whirred for what must have been 5 or 6 seconds before the light and brakes engaged. Tried it again a couple of times and same thing.

I took it back to Audi and the tech insisted that they had not touched the EPB system and it had nothing to do with them bleeding the brakes. He put it back up on the ramps and checked everything again and said there were no faults or warning lights and it was all OK. I told him that the time the motors were on when I manually released the EPB was a lot longer too and for some odd reason he just told me to not use the manual release and to use the gas pedal all the time.

We exercised the EPB about 20-30 times and it got a bit better, so now it only takes 1-2 seconds for it to engage, but I could have sworn it was virtually instant (0.5 -1 seconds) before they did the brake fluid change. Is there anything amiss here? What's the normal engagement time for the EPB with fairly healthy discs and pads? Any adjustment that can be done?

snapdragon · #2 8th November 2013, 06:42 PM

I just bled mine and agree it should not affect the EPB at all unless they did something crazily unrelated when they were down there.
It should be pretty instant, I'm surprised shy the dealer couldn't look into it further.

Lee S · #3 8th November 2013, 07:44 PM

Quote:

Originally Posted by snapdragon

I'm surprised shy the dealer couldn't look into it further.

Probably because it was 5:15pm and they wanted to clear off home.

I told them I'd be back if it didn't get better. It's been OK for now and got no worse. Maybe 1 second to fully on.

I really need to invest in a VAG-COM cable to be honest, so I can check for fault codes myself. Maybe Santa Claus will bring me one for Christmas.

PsYcHe · #4 8th November 2013, 09:29 PM

I'd say mine is probably about a second to go on properly, though I do feel the brake pedal move when it tightens on, so given that, I'd assume that it would want to do some kind of recalibration if fluid levels have changed,

snapdragon · #5 9th November 2013, 02:22 PM

Sounds normal.
My pedal sinks a bit.
If you leave the EPB off but in P and leave the car and lock it, it should do a calibration, one side at a time. Takes about a minute per side as it winds all the way in and out rather than the <1mm it takes to apply the brake.

The fluid level has no bearing on EPB, as the EPB works by turning a threaded rod with a thrust nut screwed onto it. the thrust nut doesnt turn as it is engaged loosely in the back of the calliper piston. It will push the piston on, but won't pull it back, the pads and piston will stay against the disc but not pressed on - the nut is deep and just slides back on it's own.

Lee S · #6 10th November 2013, 11:38 AM

Interesting!! Thanks snapdragon... I will give that a go later today and see what happens.

I must say, I think it's almost back to normal now. Seems a lot lot better. Can't quite understand what they did to cause it though.

Lee S · #7 11th November 2013, 10:32 PM

Thanks snapdragon. Awesome.

Put her in Park and turned ignition off and engaged steering wheel lock (keyless) and off she went, whirring and clicking. Took about a minute and now the EPB is perfect again. Exactly as it was before being "tinkered" with.... Maybe even better. So many thanks for the simple fix.

Makes you wonder why a supposed "Senior Audi Tech" couldn't just tell me to do that or even do it himself whilst we were testing it. Makes you wonder how much these folk actually know about their product/trade.... sigh !!

Cheers!!