What’s the point in the Park function of a automatic?

[durbster]

cootuk said:

At least you don't have air brakes to worry about. We don't leave wagons stood long term in gear as, if they lose air pressure, you will find yourself trying to start it in gear until you can jolt it back to neutral.

I once worked on a farm in Australia on which they had a lorry half parked in a billabong. They said somebody had gone to start it up and it had somehow driven itself into the water. I never quite understood the explanation so could it have been something like this?

It had been there ages because they'd concluded it was too difficult and dangerous to retrieve it, partly because of all the crocodiles.

[jondude]

Would not surprise me if it started out as a safety feature for San Franciso residents, then just got moved across to all automatics. The Americans love their automatics and I presume this was the first, big market for them.

The added bonus and not least ease of the park function would make sense there - and yes particularly in San Francisco where any car just relying on neutral and the handbrake is in serious danger of free rolling. Until you go there, you simply cannot imagine how steep those hills are!

[CABC]

jondude said:

Would not surprise me if it started out as a safety feature for San Franciso residents, then just got moved across to all automatics. The Americans love their automatics and I presume this was the first, big market for them.

The added bonus and not least ease of the park function would make sense there - and yes particularly in San Francisco where any car just relying on neutral and the handbrake is in serious danger of free rolling. Until you go there, you simply cannot imagine how steep those hills are!

nearly 100% of drivers used to turn their wheels into the curb too. with modern cars that habit may have eased a bit?

[ajprice]

Second Best said:

Does anybody else here have an EV with a manual handbrake? I didn't think EVs were able to have a "Park" setting, so to speak, indeed mine just has R/N/D. Disengage the handbrake and you can push it around.

I can't think of many EVs that would have a manual handbrake, VW E-Up and early or base spec Renault Zoe?

A few cars ago I had a Smart, it's an 'automated manual' gearbox. The shifter centred to neutral it was a move to the left for Drive and then + and - for up and down gears, or a move down for reverse. The American market car with the same engine and gearbox had a PRND automatic shifter

[fido]

CABC said:

nearly 100% of drivers used to turn their wheels into the curb too. with modern cars that habit may have eased a bit?

I do that just to avoid kerbing the alloys but always put it in gear when parking on a un-level surface.

[Pica-Pica]

ScoobyChris said:

sooty61 said:

I would say most people use P when they park. I never use the handbrake

In my car it engages P when the engine gets switched off anyway but I use the handbrake also. In manual cars, I’ll always leave it in gear with handbrake on.

Chris

Edited by ScoobyChris on Saturday 18th March 21:51

F30 worth ZF8 auto engage P when stationary and,
Engine is switched off
Driver’s door is opened
Driver’s seat belt it undone.
I rarely need to press P, but I do use the manual parking brake lever.
Oh, and if in a long wait in traffic, I engage neutral, put parking brake on and take my foot off the footbrake
I occasionally engage my parking brake when coming to a stop to give the shoes/drum a bit of work in order to avoid glazed brake shoes (recommended for rear discs with drum-in hat shoes).

On manuals I always leave it in gear, but my wife shuns that procedure with hers.
Many modern manual cars cannot be started unless the clutch is depressed (avoids the ‘starting in gear’ situation)

[MikeB444]

V8 Bob said:

Many moons ago had a Citroen BX handbrake was on front disc brake. If you applied it after a fast journey with hit brakes once the disc cooled and contracted the handbrake was effectively released….always had to leave in gear or be like a colleague who wondered where his car had gone!

Had this happen to me on a rear handbraked car too.
It was a brand new early model mondeo. I'd driven it back over the hills between Buxton and Congleton, parked it on the drive and 5 minutes later saw it rolling back down the side of the house.
Luckily just a tiny mark on the bumper where the wall stopped it.
I didn't think I was being that 'enthusiastic' on the brakes, but since then I've always left my cars in gear.

[donkmeister]

Wacky Racer said:

Higgs boson said:

Wacky Racer said:

You should never leave a manual car parked up in neutral.

Always in first, plus apply the handbrake....No chance of the car rolling away.

If I'm facing downhill, I stick it in reverse. You likely do, too.

Never thought of that

Not actually as smart as it might sound...

If you are going to choose the direction of your gear based on whether facing uphill or downhill, you should choose a gear in the direction of travel if your handbrake fails. You never turn an engine backwards as you can mess up the timing (the tensioners are designed for the running direction of the engine, regardless of whether the torque is applied from the wheels to the engine or the engine to the wheels).

So, facing uphill you would engage reverse, and downhill a forward gear.

However... As it's unlikely to move far enough to spin the engine (as you have doubtless turned the wheels to use the kerb to halt any progress), I'd say it's a nugatory concern whether you choose forward or reverse gears.

[donkmeister]

stevemcs said:

We see quite a few automatic cars fail there mot because the owner never uses the handbrake, personally I always use the handbrake

A Mercedes specialist near me always leaves the parking brake off - I suspect it avoids "well it worked when I dropped it off" arguments if it seizes through non use.

I think the necessity of a P-brake is case dependent too - I always use it, but it's usually unnecessary round here in an auto as the land is pretty flat. If I lived somewhere like Yorks though, I would probably think it's vital as I'd be parking on hills all the time.

[paintman]

MikeB444 said:

V8 Bob said:

Many moons ago had a Citroen BX handbrake was on front disc brake. If you applied it after a fast journey with hit brakes once the disc cooled and contracted the handbrake was effectively released….always had to leave in gear or be like a colleague who wondered where his car had gone!

Had this happen to me on a rear handbraked car too.
It was a brand new early model mondeo. I'd driven it back over the hills between Buxton and Congleton, parked it on the drive and 5 minutes later saw it rolling back down the side of the house.
Luckily just a tiny mark on the bumper where the wall stopped it.
I didn't think I was being that 'enthusiastic' on the brakes, but since then I've always left my cars in gear.

Not long after we got Mrs p's Peugeot 307 she came & asked me why I'd left her car parked halfway across the road instead of on the drive.
Told her she was the last one to drive it & I hadn't touched it or seen it since she came in.
Same issue as the above, sloping drive & fortunately we're in a Close & it hadn't made it across to the neighbours!
She's left it in gear ever since.
A quick google showed it to be a common problem across several marques.

[Got4wheels]

I just put my Transit in P when I park up. I very rarely park on any incline so never need the parking brake. I had been using it, but as mine has been heavily adapted, the 'proper' lever was replaced with a very rudimentary switch and mechanism. The mechanism is bulky and as Ford had designed the Transit not to have one so this has a smaller fuel tank to accommodate it.

Anyhow after barely 1500 miles the mechanism failed, owing to the cobbled together nature of the set up and the fact that when I locked the car, the signal also triggered the handbrake to tighten on even further. Once it go too tight, it breaks. I'm lucky mine was off when it failed. When it was replaced, the technician told me not to use it unless 'I'm parked up the side of Everest.'

Michael

[3GGy]

Rarely use the parking brake in my auto.

I have always wondered though how much wear that parking pawl receives over its life-time. Must be made out of something hardened.

160k and 20 years of abuse on mine anyway, inclines n'all.

Good luck to it.

[ScoobyChris]

Pica-Pica said:

F30 worth ZF8 auto engage P when stationary and,
Engine is switched off
Driver’s door is opened
Driver’s seat belt it undone.

Ah yes this reminds me of the fun and games I had trying to manoeuvre my car (hanging out the open door) so i could get the jacking point in a good spot and it kept putting it in Park and bonging at me.

I’m sure the design is well intended but a bit nanny state for me.

Chris

[Pica-Pica]

ScoobyChris said:

Pica-Pica said:

F30 worth ZF8 auto engage P when stationary and,
Engine is switched off
Driver’s door is opened
Driver’s seat belt it undone.

Ah yes this reminds me of the fun and games I had trying to manoeuvre my car (hanging out the open door) so i could get the jacking point in a good spot and it kept putting it in Park and bonging at me.

I’m sure the design is well intended but a bit nanny state for me.

Chris

Yes, if, on a rare occasion, I wanted to move my old manual E36 a metre or so, I could put it into neutral and push it at the A pillar. Now, I can’t put the ZF8 into neutral unless the engine is started - then I may as well drive it that metre.

[emperorburger]

donkmeister said:

Not actually as smart as it might sound...

If you are going to choose the direction of your gear based on whether facing uphill or downhill, you should choose a gear in the direction of travel if your handbrake fails. You never turn an engine backwards as you can mess up the timing (the tensioners are designed for the running direction of the engine, regardless of whether the torque is applied from the wheels to the engine or the engine to the wheels).

So, facing uphill you would engage reverse, and downhill a forward gear.

However... As it's unlikely to move far enough to spin the engine (as you have doubtless turned the wheels to use the kerb to halt any progress), I'd say it's a nugatory concern whether you choose forward or reverse gears.

You can't remove the keys from the ignition on my old manual Corvette unless it's in reverse, likewise once the keys are removed you can't disengage reverse gear. Quite possibly an anti theft measure more than anything else. The handbrake itself is next to useless.

In so far automatics, always used park and never applied the handbrake. It's a bit different now with drive by wire as the handbrake functions are often automated.

[caziques]

Some of the replies in this thread are quite unbelievable.

When parking on a hill the front wheels should always be angled to prevent a runaway, regardless of auto or manual.

Most US auto drivers never use the handbrake (or parking brake), it's generally referred to as an emergency brake.

I thought everybody put a manual car in gear when parked, seems so obvious to me.

[carl_w]

I've recently acquired an EV (BMW i4) that has a park button on the "gear" stick and an automatic parking brake. I suspect they both do the same thing.

[Nickbrapp]

What happens if you put an auto into park when you’re driving along? My transit has a big clunky gear lever for the auto box and I feel it would cause me to crash but I still want to try it

[donkmeister]

Nickbrapp said:

What happens if you put an auto into park when you’re driving along? My transit has a big clunky gear lever for the auto box and I feel it would cause me to crash but I still want to try it

I did it in a rental once at about 10mph... It made a ratcheting sound (which makes sense as the park mechanism is a big ratchet) and then stood on its nose.

No damage done, but I have heard tales of pawls breaking off.

ETA it was a hateful, hateful Peugeot 30-something with a 4-speed slushbox and about 2 horsepower. This was a new car in the 2010s, when 6-speed autos were already typical of that class of car and most small engine stuff had a turbo to make up for the lack of capacity. Aagh I wanted to hurt it. Hence the "experiment" as I reached my house.

Edited by donkmeister on Sunday 19th March 19:30

[Teddy Lop]

Nickbrapp said:

What happens if you put an auto into park when you’re driving along? My transit has a big clunky gear lever for the auto box and I feel it would cause me to crash but I still want to try it

Depends how tough the transmission is I guess, I know someone with a delica which have a column shifter controlling some lumpy old yank unit and he shoved the shifter into r or p instead of flipping the indicator on the motorway... It survived. Kinda think whatever my transit has would be a whole lot more explodey and expensive.