Xoutpost.com - auto hold question

Xoutpost.com (https://xoutpost.com/forums.php)

- X5 (E70) Forum (https://xoutpost.com/bmw-sav-forums/x5-e70-forum/)

- - auto hold question (https://xoutpost.com/bmw-sav-forums/x5-e70-forum/106468-auto-hold-question.html)

auto hold question

Say I'm stopped at a light and engage auto hold and take my foot off the brakes. Does the auto hold feature actually keep the brake pads applied or does it release that and engage the parking brake only?

I'm curious because for instance I'm coming down a series of long hills and have hot brakes, I don't want to imprint that on the rotors at a long stoplight.

Quote:

Originally Posted by rh71 (Post 1111357)

Say I'm stopped at a light and engage auto hold and take my foot off the brakes.

1. Does the auto hold feature actually keep the brake pads applied?
2. Or does it release that and engage the parking brake only?

I'm curious because for instance I'm coming down a series of long hills and have hot brakes, I don't want to imprint that on the rotors at a long stoplight.

See answer from DH from back on 4/17/16:

Quote:

Originally Posted by Doug Huffman (Post 9631222)

Automatic Hold
The concept
This system assists the driver by automatically setting and releasing the brake, such as when moving in stop-and-go traffic.

The vehicle is automatically held in place when it is stationary.

On inclines, the system prevents the vehicle from rolling backward when driving away.

For your safety
Automatic Hold is deactivated automatically and the parking brake is set when:

The engine is switched off.
A door is opened and the driver's safety belt is unbuckled.
The vehicle is braked to a standstill with the parking brake while driving.

^ thanks I did find that description via google as well, but I'm not clear on whether it releases the actual brake pads when I release the brake to auto hold. Or does it hold the pads to the rotors as well (somehow) AND activate the parking brake?

I can say that there is zero roll-back/forward when I use auto-hold, which is different than when I park in my driveway with the parking brake - it rolls slightly. This leads me to think the pads are still holding too with auto hold.

That being said, when I park with the parking brake, it holds tight, especially when it's still in gear. It rocks when you turn the engine off. Unless I am mistaken. I will test that later.

Sent from my iPhone using Tapatalk

Yes that's true - it's after you turn the engine off. The real test would be to engage the parking brake and release the brake and see if it moves.

I believe it uses your actual brakes, not parking brakes. You can see your rear brake light illuminated when auto hold is applied.

Yeah, but I wouldn't say that means it uses the brakes because that could be one line of code. Only way to find out for sure is get someone to watch the brakes as you activate it. Or a camera. Or if you really want, you can try to measure the brake fluid pressure. Maybe someone knows from experience?

Sent from my iPhone using Tapatalk

It works off the stability control and uses the front brakes, apparently not too aggressively. You may notice a slight creep if you use the system with the ac on. About 1/8 of an inch every 30 seconds or so.