electronic hand brake

[roger mcnab]

just read a bit that new cars are being fitted with electronic hand brakes good or bad idea if switch fails can one release the brake or apply it who knows
just wondering
cheers roger

[Bob46320]

So in an emergency brake failure - handbrake fully on ???

[mab01uk]

I was watching one of those 'Motorway Cops' TV programmes recently and the Police were trying to move a Range Rover Evoque which had broken down in a live lane but the Police could not disengage its electronic hand brake. In the end they dragged the Evoque with both rear wheels locked on a tow rope behind the Police patrol car to a safer place to await a recovery vehicle....I think the rear tyres may have ended up with flat spots.

[Polarsilver]

Landrover have big issues with electronic handbrakes they fail on regular basis .. i spent 18 hours hands on to remove the Handbrake unit on my sons Discovery .. priced up parts needed & given the value of the Car its not worth the spend to repair .. So car is now scrap .

[Mudhen]

Certainly nothing new using electronic parking brakes...LR has been using them since Discovery 3s in 2005. We've had 4 LRs with them over those years and (thankfully) never had an issue - other than trying to figure out how to retract them for brake servicing! Just last weekend in particular with our Evoque - 'pull parking brake lever for one second...hold accelerator to floor for one second...turn car off then on quickly'.

And then what? I can't turn the car off for the entire brake service?!!

[peasantslife]

I'm inclined to suggest they are electrically powered handbrakes, whilst I dont doubt there is an element of electronics its simple stuff for a canbus equipped car, sense the switch position and motor until a cut of torque is achieved at one end or a stop at the other.. Difficulty lies in that they haul the brake on so hard - no opportunity for the driver to moderate the clamp to suit the circumstance. My brother runs very high milage up and down the motorways of the UK, with cars under 4 years old. He got so fed up with VW passats jamming their electric handbrakes he just wont use the switch - ever, and switches off using the service procedure without it engaging.

[MagicWandWoody]

...so fed up with VW passats jamming their electric handbrakes he just wont use the switch...

A friend's old Passat had a brick in the passenger footwell. Never used the electrical handbrake because it would fail 'on' so often - instead plonked the brick in front of a wheel on any slope. He's just swapped it for a Seat... with the same type of handbrake. So I expect to be stubbing my toe on that damn brick again pretty soon.

[imack]

At slow speed, below 5 -10 mph, the hand brake 'switch ' applies the parking brake. You have no control over it, it's just maximum braking effort applied to the rear wheels. At speeds over about 10 mph the hand brake switch applies maximum braking effort via the ABS unit to all four wheels. You can't release the han brake until the vehicle comes to a full stop. I applied one of these electronic parking brakes at about 50mph, it was quite interesting!!!
Early systems apply the parking brake conventionally by an actuator operating the hand brake cables, later systems do away with the cables, and the actuators are in the calipers.