Parking brake

[macd2401]

Tried this at work this morning, having stopped the car, but let the auto brake hold the vehicle. Taking my belt off put the parking brake on, and when I tried to take power, I felt the car try to move.

In fairness, unless you're horsing it, the spring compression is enough to give you a heads up that the brake is still on...

As an aside, and for no reason other than a reckless urge of "I wonder what it actually does", I also tested the emergency brake function, the parking brake switch whilst moving. Sounds awful, but it's effective. If I had falsers, they'd have ended up on the dash somewhere Just be aware that the brakes only stay on as long as you pull the switch. Let go, and they come straight off.

 

[peterkins]

Thanks for your observations, guys. Car is going in for its first service soon with only 3500 on the clock. Damn Covid. I'll talk to the service chappie about the issue encouraged by knowing its not just me.

Having built security and safety critical systems in a previous life I know that a design criteria is that the "service" what ever that may be must not be offered to the consumer in an insecure or unsafe state. Clearly, its not unsafe to leave the brakes on when you try to start to move but it demonstrates a lack of engineering discipline that might exhibit itself in the system elsewhere too.

In the case of the MG ZS EV, their software has enough wit to turn on and off the light and engage the brake as appropriate, the same logic should be employed to inform the motors that they should not attempt to turn if the brake is on. Its not hard - they just got it wrong.

macd2401: thanks for doing the "chuck a spanner in the gears while the engine is turning" test. A more brave chap than I. Your're right that on a solid road the car rocking on the suspension is a bit of a give-away that the brakes haven't released when they should have done. However, on gravel its a different experience. My cat has learned to head for the bushes when I get in the car.

 

[Kithmo]

Yay, handbrake and J turns are possible

 

[peterkins]

Gotta get one of them air scoops for my EV. If I could get something to push fumes out the back the illusion would be complete.

 

[Gomev]

Thanks for your observations, guys. Car is going in for its first service soon with only 3500 on the clock. Damn Covid. I'll talk to the service chappie about the issue encouraged by knowing its not just me.

Having built security and safety critical systems in a previous life I know that a design criteria is that the "service" what ever that may be must not be offered to the consumer in an insecure or unsafe state. Clearly, its not unsafe to leave the brakes on when you try to start to move but it demonstrates a lack of engineering discipline that might exhibit itself in the system elsewhere too.

In the case of the MG ZS EV, their software has enough wit to turn on and off the light and engage the brake as appropriate, the same logic should be employed to inform the motors that they should not attempt to turn if the brake is on. Its not hard - they just got it wrong.

macd2401: thanks for doing the "chuck a spanner in the gears while the engine is turning" test. A more brave chap than I. Your're right that on a solid road the car rocking on the suspension is a bit of a give-away that the brakes haven't released when they should have done. However, on gravel its a different experience. My cat has learned to head for the bushes when I get in the car.

Just so I'm clear,
are you saying that if the parking brake is on i.e. you are in 'Park' when you press the Go pedal it tries to go ?
or
are you saying when you are in 'Drive' or 'Reverse' and the brake is on, when you press the Go pedal it tries to go ?

The former I would not expect, the latter I would expect. (I think)

 

[SCB86]

My car won't disengage the handbrake if I try to pull away without a belt on, it will even strain against the brake if you push the accelerator.

 

[Cocijo]

Can you release it manually?

 

[Lovemyev]

I checked on my car yesterday.
The car is parked on a slight decline on our driveway.
When entering the car, foot hard on the foot brake, then with pressure still applied, hit the “Start” button.
When the car has booted to the full “READY” mode, turn the gear selector to “R” to reverse off the drive.
Release the pressure from the foot brake and tap the “GO” pedal.
The handbrake will release and with slight pressure on the “GO” pedal, the car will slowly pull back wards.
AT THIS POINT - I DID NOT HAVE MY SEAT BELT IN PLACE !.
It would allow me to switch to “D” mode and pull away.
When I hit about 15 - 20 Mph - The car gave out the seat belt warning .
My previous VW would not allow this type of behaviour.
To move the car, the drivers door would have to be totally closed and the seat belt in place.
Otherwise it would NOT release the electronic hand brake.
It would NOT allow you to reverse the car with the drivers door slightly open either !.

 

[Dodger]

I checked on my car yesterday.
The car is parked on a slight decline on our driveway.
When entering the car, foot hard on the foot brake, then with pressure still applied, hit the “Start” button.
When the car has booted to the full “READY” mode, turn the gear selector to “R” to reverse off the drive.
Release the pressure from the foot brake and tap the “GO” pedal.
The handbrake will release and with slight pressure on the “GO” pedal, the car will slowly pull back wards.
AT THIS POINT - I DID NOT HAVE MY SEAT BELT IN PLACE !.
It would allow me to switch to “D” mode and pull away.
When I hit about 15 - 20 Mph - The car gave out the seat belt warning .
My previous VW would not allow this type of behaviour.
To move the car, the drivers door would have to be totally closed and the seat belt in place.
Otherwise it would NOT release the electronic hand brake.
It would NOT allow you to reverse the car with the drivers door slightly open either !.

 

[Dodger]

My car does exactly the same as yours, often drive out in the morning get up to about 20mph and get the seat belt warning. If my wife with me i drive about 2yds and get a warning from her!

 

[chromeskull]

If my door is open with my belt off it will not allow the car to move, it will apply the parking brake even if I took it off.
Close the door with belt off and it will allow you to drive without one. But it will complain about it.