Park brake failure?!

(14-02-2013 02:32pm)speary Wrote:  It won't release in second gear even though it says it will in the manual

I stand corrected , can't check as i'm in the middle of the north sea

There are two values of clamp load that is applied by the EBP based on the gradient that the vehicle is on. If the gradient is less than 10%, the EBP applies a clamp load of 13.5 kN to the brake pads. But on gradients of 10% or more, it applies 16.5 kN.

Assuming you applied the EBP on a flat surface, it was the low (13.5 kN) clamp load that it put on, which might not have been enough to hold the car stationary. According to you, there was a constant pulling load because you kept the transmission in D and, at the time, the brake pads/discs could have been slippery (exposed to contaminations from snowy roads). Your car moved forward not because the EBP released, but because the parking brake pads slipped. When you put the transmission back to P, there was no pulling load and that's why it held successfully. It might work some other times, but not this time. So, I'd say there is nothing wrong with your car.

However, you can manually force the EBP to apply full clamp load (of 16.5 kN) regardless of the surface gradient the car is on by pulling and holding the EBP switch for more than 3 seconds.

Thanks Bowl,
That makes perfect sense.

(14-02-2013 05:40pm)Bowl Wrote:  There are two values of clamp load that is applied by the EBP based on the gradient that the vehicle is on. If the gradient is less that 10%, the EBP applies a clamp load of 13.5 kN to the brake pads. But on gradients of 10% or more, it applies 16.5 kN.

Assuming you applied the EBP on a flat surface, it was the low (13.5 kN) clamp load that it put on, which might not have been enough to hold the car stationary. According to you, there was a constant pulling load because you kept the transmission in D and, at the time, the brake pads/discs could have been slippery (exposed to contaminations from snowy roads). Your car moved forward not because the EBP released, but because the parking brake pads slipped. When you put the transmission back to P, there was no pulling load and that's why it held successfully. It might work some other times, but not this time. So, I'd say there is nothing wrong with your car.

However, you can manually force the EBP to apply full clamp load (of 16.5 kN) regardless of the surface gradient the car is on by pulling and holding the EBP switch for more than 3 seconds.

Yea think the snow probably did have something to do with it as the car's been ok today. Didn't know about the full clamp when holding ebp for more than 3 secs - thanks for that! Learnt something new