VF Parking Brake Issue

[lmoengnr]

I laughed but it ain’t funny when you want to wind the window up and the emergency brake slams on

At least we know that it is an emergency brake as well and not just a park brake

No, it's not an emergency brake.
If you accidently apply it, it releases straight away.

 

[Skylarking]

No, it's not an emergency brake.
If you accidently apply it, it releases straight away.

What happens if you hold the button up?

I thought all cars must have an emergency brake but can't remember which ADR relates to it.

A quick google didnt find much (other than ADR now mandates automat emergency braking on new cars) but i did find the following*

Emergency brakes, including parking brakes intended to provide emergency braking such as those on vehicles, which do not have split system service brakes or are not subject to ADR31, or ADR35 must be capable of either:​

• stopping the vehicle on a dry smooth surface free from loose material, within the distance specified in Table 2
• achieving the deceleration rate specified in Table 2

It seems emergency brakes, other than on trucks and big trailers, are no longer needed because we have redundancy built into the main brakes via split system.

The VF commodore has a split system master cylinder which has two independant hydraulic circuits but they both go to the ABS which is a single pount of failure? The ABS does all sorts of trickery to manage things like the done by the old mechanical proportioning valve (now an ABS software function called Electronic Brake Force Differential, EBD) .

So where is the redundancy that is required so we no longer need emergency brakes? After all, a single failure of the ABS control system and you loose all front/rear brake pressure proportioning even though you have a split hydraulic circuit (that goes to a common ABS module>).

Obviously these ABS system have been working for years without noticable issues but it wouldn't surprise me that the basicas is predicated on only complience testing for a single fault mode and/or the diagnostics system checks everything on vehicle start and warns the driver if there is an anlmoly.

Don't know the ins and outs but i've always liked the security/idea of a hand brake i could pull on should the main brakes not work... And been in a car when the driver has had to do just that (and it had a split braking circuit as well)...

Go figure, regulation?

I haven't looked at the VF owners manual to see what they say on the matter.

* https://www.vicroads.vic.gov.au/-/media/files/documents/safety-and-road-rules/vsi26.ashx (results in a download of a Vicroads PDF).

 

[chrisp]

What happens if you hold the button up?

I thought all cars must have an emergency brake but can't remember which ADR relates to it.

A quick google didnt find much (other than ADR now mandates automat emergency braking on new cars) but i did find the following*

Emergency brakes, including parking brakes intended to provide emergency braking such as those on vehicles, which do not have split system service brakes or are not subject to ADR31, or ADR35 must be capable of either:​

• stopping the vehicle on a dry smooth surface free from loose material, within the distance specified in Table 2
• achieving the deceleration rate specified in Table 2

It seems emergency brakes, other than on trucks and big trailers, are no longer needed because we have redundancy built into the main brakes via split system.

The VF commodore has a split system master cylinder which has two independant hydraulic circuits but they both go to the ABS which is a single pount of failure? The ABS does all sorts of trickery to manage things like the done by the old mechanical proportioning valve (now an ABS software function called Electronic Brake Force Differential, EBD) .

So where is the redundancy that is required so we no longer need emergency brakes? After all, a single failure of the ABS control system and you loose all front/rear brake pressure proportioning even though you have a split hydraulic circuit (that goes to a common ABS module>).

Obviously these ABS system have been working for years without noticable issues but it wouldn't surprise me that the basicas is predicated on only complience testing for a single fault mode and/or the diagnostics system checks everything on vehicle start and warns the driver if there is an anlmoly.

Don't know the ins and outs but i've always liked the security/idea of a hand brake i could pull on should the main brakes not work... And been in a car when the driver has had to do just that (and it had a split braking circuit as well)...

Go figure, regulation?

I haven't looked at the VF owners manual to see what they say on the matter.

* https://www.vicroads.vic.gov.au/-/media/files/documents/safety-and-road-rules/vsi26.ashx (results in a download of a Vicroads PDF).

My recollection is that if the handbrake is applied when the car is moving (fast), it doesn’t activate the handbrake drum baking unit, but instead uses the ABS unit to apply the disc brakes instead. It apparently brakes the car at 0.5G until the car slows below some designated speed before applying the real handbrake.

I haven’t tried it out personally, but I’d be interested in hearing if anyone has.

Just to clarify, the first paragraph is basis on my memory of similar discussions that have happened on this forum, and someone posting the operation description from the manual.

 

[greenacc]

I much prefer a proper handbrake over the silly fingerbrake.
And coming from a VE, which has the driver window controllers in a similar position to the VF fingerbrake, it caused a bit of a problem...

I have done the same but luckily a message popped up on the dash, 'HAND BRAKE DENIED' or something close to that. I think I felt a tug for a split second then it seemed to figure out what was about to happen and said No.
I genuinely think half the money spent developing the VF was wasted on how to make it different to the VE just for the sake of being different. And most of those differences are LESS good than the original. Ie the VE cluster was years ahead of the VF binnacle nonsense that reminds me of vintage Chevy.

 

[lmoengnr]

What happens if you hold the button up?

I was curious, but not curious to try that!
I was barely rolling out of a car park when I decided to shut the window and applied the fingerbrake instead.
It applied then released straight away, slowed the car down but didn't stop it.
Not sure about a message on the DIC, I was trying to kick my own arse for doing such a stupid thing.

 

[chrisp]

A couple of screen shots from the VF1 service manual…

 

[RevNev]

I don’t like EPB’s and much prefers the old mechanical level and cables that go directly to the rear drums/discs. No chance of the driver getting confused when you can look down and see a level that’s still pulled up. No chance of the car rolling away unless the driver actively releases the handbrake.

You can't do a handbrake turn as easily with no lever modulation either! It's the reason M2/3/4 BMW's retained the lever mechanical handbrake where most of the others are now electric.

 

[VF300k]

No, it's not an emergency brake.
If you accidently apply it, it releases straight away.

I think reading the owners manual it does make mention of being able to use it as a emergency brake

A couple of screen shots from the VF1 service manual…



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View attachment 257544

Looks like a more advanced version of what the owners manual says

“If the EPB is applied while the vehicle is in motion, a chime will sound, and the DIC message RELEASE PARK BRAKE SWITCH will be displayed.

The vehicle will decelerate as long as the switch is held in the up position. Releasing the EPB switch during the deceleration will release the parking brake.

If the switch is held in the up position until the vehicle comes to a stop, the EPB will remain applied.

Rang the local holden service centre, apparently it would cost $148 p/h just for them to diagnose the problem, for that price I think I’ll do some of the checks suggested here before forking over some dosh to get it looked at

 

[Anthony121]

A couple of screen shots from the VF1 service manual…



View attachment 257543




View attachment 257544

I wish I played with this a bit more when I had the opportunity in the company cars . I only lifted the brake switch and let it go.

 

[Skylarking]

I think reading the owners manual it does make mention of being able to use it as a emergency brake

Seems that what the workshop manual is saying but it’s not the EPB that actually stops you. Above 15kph pulling the EPB button up and holding it activates ESC to slow you down until you stop, then EPB applies the park brake according to then workshop manual and this lines up with what seems to be stated within the owners manual. ESC is performed by the ABS system using the main brakes.

Still doesn’t resolve my lack of understanding of where the redundancy is within hydraulic brake system MC & ABS) which means an independent emergency handbrake may no5 be needed