Auto hand brake

[Philip Fisher]

Originally Posted by Fursty Ferret

Autohold applies the brakes via hydraulic pressure. The handbrake is a different system.

Yes. I hear it applying when I switch off and the A on the dash changes to a P.

[Philip Fisher]

Originally Posted by nu11eaf

My 2017 D5 XC90 does not go into park when you switch the engine off, in fact you can't turn the engine off until you put it in park position, when in park it will hold the car by locking the transmission up, without the use of the parking brake.
Although I do have mine set to apply the parking brake automatically when engine is turn off, the auto hold then changes to red parking brake symbol.
Having to put it in park before turning engine off is the default safety measure to stop car rolling by locking the transmission on my D5.

The T8 may be set up differently.

The T8 has a "joy stick type" gear selector, rather than a conventional auto gear selector. To select gears you just click back or forward and it springs back to centre. It therefore can go into park automatically as it does not need to be physically moved to select Park.

This is the Swedish crystal gear selector that was touted as a feature when the car was launched and also why my Nephew calls me "Uncle Crystal Knob".........

[EssexExile]

Originally Posted by Scotia64

Thanks guys , I did what you recommended and the box was already unticked.

Have you looked in driver profiles?

[Philip Fisher]

So. In reply to the original question I did some investigation when i popped down to the shops for the paper.

Firstly the gearbox. In a T8, whatever the brake settings, the gearbox will always go into park if you turn off the engine. I believe in D5/T6/T5s with the conventional gear selector you have to physically put it into park before the car will allow you to switch off.

Now the parking brake (shown as P in a circle on the dash).

There is indeed a tick box to activate this on engine switch off. With this ticked, the parking brake (P in a circle) will always come on when you switch off.

The other thing that could be active is the autohold which is switched on using the "A" button next to the parking brake switch. When autohold is activated an A in a circle is shown on the dash. If the A in a circle is shown and you then switch off the engine then the parking brake activates, the A changes to a P in a circle on the dash and you can hear it come on if you have the window open.

If you have the tickbox in sensus un-ticked but you have autohold switched on, and quickly turn off the engine before it gets chance to be activated (ie no A in a circle is displayed on the dash) then the car does not activate the parking brake. There is no P in a circle displayed and the car simply rolls a smidgen before the locked autobox stops it rolling any further.

So if you wish for the car to always reliably never apply the handbrake on switch off, then you need to make sure that in Sensus this option is un-ticked AND you have autohold swtiched off.

Or of course you just take the handbrake off manually after you have switched the engine off.......

Hope that makes sense, and I at least learned something today.

[MK09]

Originally Posted by Scotia64

Is there anyway to turn off the auto hand brake?
My car hasn’t move for a month until today, when I reversed the car out of my garage there was a distinct thump as the brakes released, for about 4 miles the there was a rubbing sound .

Excuse my ignorance on this but what causes this and how does turning off the auto hand brake help? I had exactly the same issue on my XC90 after not using it for 2 weeks recently - big thump on releasing the brakes and very juddery brakes for a few miles afterwards.

[volvo s60 2001]

Is there a way to turn off the engine in neutral on T8 and the parking brake not to be applied. Let's say you go in a garage where you need to switch off the engine, step of the car and the car to be pushed to be adjusted on the ramp.

[nu11eaf]

Originally Posted by MK09

Excuse my ignorance on this but what causes this and how does turning off the auto hand brake help? I had exactly the same issue on my XC90 after not using it for 2 weeks recently - big thump on releasing the brakes and very juddery brakes for a few miles afterwards.

My guess is that the parking brake motor backs off the pistons but the brake pads have remained hard on the discs and come off with a clunk once you start rolling, the pad at the rear of the disc (piston side) is held in the piston by spring clips and could allow piston to move and pad to stay on disc, (the spring clips would still be in the piston but not fully, they would seat fully again once brakes are applied again.
Not applying the parking brake if car is stood a long time would stop this happening,

You can see the type of clips that just push in to the piston in the photo on this add, (used for illustration only) these are not the correct ones for spa model but have same clips.

https://www.ebay.co.uk/itm/MINTEX-RE...edirect=mobile

[Scotia64]

Originally Posted by Philip Fisher

So. In reply to the original question I did some investigation when i popped down to the shops for the paper.

Firstly the gearbox. In a T8, whatever the brake settings, the gearbox will always go into park if you turn off the engine. I believe in D5/T6/T5s with the conventional gear selector you have to physically put it into park before the car will allow you to switch off.

Now the parking brake (shown as P in a circle on the dash).

There is indeed a tick box to activate this on engine switch off. With this ticked, the parking brake (P in a circle) will always come on when you switch off.

The other thing that could be active is the autohold which is switched on using the "A" button next to the parking brake switch. When autohold is activated an A in a circle is shown on the dash. If the A in a circle is shown and you then switch off the engine then the parking brake activates, the A changes to a P in a circle on the dash and you can hear it come on if you have the window open.

If you have the tickbox in sensus un-ticked but you have autohold switched on, and quickly turn off the engine before it gets chance to be activated (ie no A in a circle is displayed on the dash) then the car does not activate the parking brake. There is no P in a circle displayed and the car simply rolls a smidgen before the locked autobox stops it rolling any further.

So if you wish for the car to always reliably never apply the handbrake on switch off, then you need to make sure that in Sensus this option is un-ticked AND you have autohold swtiched off.

Or of course you just take the handbrake off manually after you have switched the engine off.......

Hope that makes sense, and I at least learned something today.

I’ll check the sensus set up tomorrow.

[Philip Fisher]

Originally Posted by nu11eaf

My guess is that the parking brake motor backs off the pistons but the brake pads have remained hard on the discs and come off with a clunk once you start rolling, the pad at the rear of the disc (piston side) is held in the piston by spring clips and could allow piston to move and pad to stay on disc, (the spring clips would still be in the piston but not fully, they would seat fully again once brakes are applied again.
Not applying the parking brake if car is stood a long time would stop this happening,

You can see the type of clips that just push in to the piston in the photo on this add, (used for illustration only) these are not the correct ones for spa model but have same clips.

https://www.ebay.co.uk/itm/MINTEX-RE...edirect=mobile

I once cleaned my V70 T5 (phase 1) and cleaned the wheels with wonderwheels acid cleaner. The car then sat on the drive for a week before I wanted to use it (rather inconveniently for a European camping holiday). When I came to move it the rear brakes were as good as welded on (they had an internal drum brake for the parking brake on this model). RAC were no help, hitting with a lump hammer no good either. In the end we went in the other car. When I got home I just decided to drive it down the road and see what happened. Luckily both rear brakes released about half way down our short close. The shoes were toast though, completely ripped apart. I think I saved the disks, put new shoes on it and the car was sold soon after anyway.

[Scotia64]

Thanks to everyone on here I’ve found out that you can release the handbrake manually. No lights come on the dash to say the handbrake or any other brake has been applied automatically anyway but I released the handbrake just in case.
The car has been sitting for about a week , the next time it moves will be on Tuesday as I’m going to a funeral, we’ll see what happens with the brakes then.