Line locker as a park brake ???

[kyleb]

Originally Posted by twobjshelbys

When I see things like this the question I always ask is "it seems like an obvious solution, and if it was a good idea it would already be the solution". Since it isn't there's probably something that doesn't work well. Standard mechanical parking brake always works. Doesn't need battery.

I have a BMW X5M that has a button (electric) for the parking brake.
Too scared to push it to see if it works as an emergency brake as well.

[twobjshelbys]

Originally Posted by kyleb

I have a BMW X5M that has a button (electric) for the parking brake.
Too scared to push it to see if it works as an emergency brake as well.

The ECU probably prevents it from being activated if the vehicle is moving or maybe even if not in neutral.

[kyleb]

Originally Posted by twobjshelbys

The ECU probably prevents it from being activated if the vehicle is moving or maybe even if not in neutral.

I should probably get the owners manual out but where’s the fun in that?

[Gaz64]

I don't think the switch just applies the parkbrake in an emergency. Can you imagine an electric parkbrake locking up the rear wheels with no modulation possible?
Appling the parkbrake switch in many cars at speed above about 8 mph actually applies the hydraulic brakes on ALL wheels to slow the car quickly and safely to a stop.
Great aid for a medical emergency, especially for a passenger.

[spdbrake]

I wouldn't activate yours while at speed Kyleb. The X5 only pulls the normal emerg rear cables for you via a motor and gearbox VS a lever.

https://www.youcanic.com/vehicle/bmw...ke-malfunction

[kyleb]

Originally Posted by spdbrake

I wouldn't activate yours while at speed Kyleb. The X5 only pulls the normal emerg rear cables for you via a motor and gearbox VS a lever.

https://www.youcanic.com/vehicle/bmw...ke-malfunction

No problem.. I’ll ask a mate to try it on his then.

[1795]

Originally Posted by Gaz64

I don't think the switch just applies the parkbrake in an emergency. Can you imagine an electric parkbrake locking up the rear wheels with no modulation possible?
Appling the parkbrake switch in many cars at speed above about 8 mph actually applies the hydraulic brakes on ALL wheels to slow the car quickly and safely to a stop.
Great aid for a medical emergency, especially for a passenger.

Gary,

Back when I was young and stupid, as opposed to old and stupid, we used to take our cars out in parking lots or on rarely used back roads and at about 50 mph would pull on the emergency brake (which was mechanical) and slide to a top. Left a lot of rubber on the road and you had to react quickly.

It seems like the emergency brake, which was meant to stop the vehicle by a progressive mechanical means if the hydraulic system failed, has transitioned to more of a paring brake meant to lower the risk that a car would roll when parked. With a properly set emergency brake you would have a difficult time moving the car under power. Most parking brakes today will not stop you from moving the car under power.

Jim

[Gaz64]

Jim,

Pre 2005 cars with a well adjusted hand brake should be able to stop the car albeit with less g force than all 4 wheels.

Many cars can slide to a stop if adjusted well. Some will hold well under power.

Some cars I know that have "electric park brake" are a switch operated electric servo operated cable operated mechanical handbrake within the rear brake rotors.

If the car is driven away from a stop, the electric park brake is released automatically, so impossible to drive with the park brake on.

When the switch is operated at some speed, the normal hydraulic braking system is operated, and they do stop VERY well from all 4 wheels braking.

I was a sceptic at first, until a GM trainer showed me on a drive.

If you get a chance, try it in a late model car with electric park brake.

I think that many cars that have this now would use similar architecture.