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Run Away Car
ash_hammond - 7/8/06 at 09:33 AM

Morning Chaps.

Last night after coming off a long drive I parked my car out side my parent’s house, which is on a sheepish hill. I applied the hand brake and exited the car as normal. After being in the house 15 or so minutes I heard some one yell - "The car is moving down the road" Luckily or maybe not the neighbors car was only 6ft away so my car gently nudged into theirs and no major damaged - just a few scuffs.

What I found strange was, the car had managed to stop still on the hill for 15 minutes and then decided to roll. The handbrake was applied (checked it when re-entered the car. After the event had unfolded it was decoded that the rear discs must have been hot - therefore slightly expanded. Now the car had been stood and the brakes had cooled, it had allowed the handbrake to slacken slightly, just enough to allow the car the move slowly. If the car had been parked on the flat there would have not been enough force to move to car.

Has any one ever come across this before?

Cheers

Ash


muzchap - 7/8/06 at 09:34 AM

Nope - that's gutting

Keep it in 1st if parked on an upwards slope, if on a downwards slope, leave in Reverse.

I never trust handbrakes on a slope...

HTH.


melly-g - 7/8/06 at 09:38 AM

yes a mate at work had the same with his Bora! Parked in his drive Quite a steep hill and looked out of his window before going to bed to see his car parked in his neighbours hedge! It just missed the front of Neighbours car as well.

As you say disks expanding then cooling once stood! Leave it in gear as well!


mookaloid - 7/8/06 at 09:38 AM

Citroens used to be famous for this - it isn't a citroen is it?


graememk - 7/8/06 at 09:43 AM

my citroen c5 used to do it

i got used to leaving it in gear, seeing as i live in lincs its not second nature parking on hills anyway


Agriv8 - 7/8/06 at 09:49 AM

Citreon BX did it twice .

Handbrake used to be on front wheels to allow them to sag as the suspension dropped .

second occassion it rolled accross a road
between 3 parked cars and came to rest on a rockery.

Regards

Agriv8


ash_hammond - 7/8/06 at 09:49 AM

No not a citroen, 06 Focus. Before the event happened i tested (with me in the car :-) ) to see if the car would hold on the hill in gear, the hill is that steep that there is enough force to turn the engine and gearbox over and force the car down the hill at a decent speed. After those results i never bothered leaving it in gear, if the hand brake cable snapped it would have rolled regardless.

I think the saying is

"shit happend" :-(

What made the situation worse was the neighbour had 10 ppl round for a bbq so the whole bloody familly had to come for a gorp! and express their views.

ash


NS Dev - 7/8/06 at 10:12 AM

ahhh hilly sheffield!!

Was up there this weekend funnily enough. Popped up to derwent ressy with my girlfriend and there were a few dax rushes around up there, anybody on here?


02GF74 - 7/8/06 at 10:41 AM

quote:
Originally posted by mookaloid
Citroens used to be famous for this - it isn't a citroen is it?


nope; thinik it was the laguna - advertising slogan was "it's moving evenwhen it is still" or somethig lke that - use to rooll away all the time.

A prper car like a volvo wpold have drums as well as rear discs fopr this reason.


mike smith1 - 7/8/06 at 11:04 AM

My friend is a ford mechanic and the exact same thing happend to him at work with a brand new st mondeo, except it wiped out a st focus with it oops!

Mike


Avoneer - 7/8/06 at 11:07 AM

Put it in 5th gear then!

I always leave my car in gear.

Makes it harder to steal as well if they want to drag it onto a trailer after cutting the handbrake cables.

Pat...


Syd Bridge - 7/8/06 at 11:35 AM

It's always best to leave a car parked 'in gear'.

Although, here in UK, I'm told it is a fail at licence test time if you do so.

In Aus, the exact opposite. Leave the car parked out of gear and you've failed.

Also, should leave it parked on hills with the front wheels turned into the kerb, just in case the sort of thing described above happens.

'In Gear', would seem the most obvious and common sensible. To me at least.

Cheers,
Syd.


romer - 7/8/06 at 12:20 PM

Seen this happen quite few times with road rally cars.
Sitting there waiting for results, eating your breakfast while looking out the window and trying to keep awake after the night long sport - then you see a driversless car slowly, silently and earily float past the window . . WOW, you sure wake up with a start. Never seen so many sleepless people move as quick

Yup, down to hot rear brakes.

Romer


MikeRJ - 7/8/06 at 12:44 PM

Yes, this is a far from uncommon occurence with rear discs. A drums brake will get tighter as it cools (and the drum contracts) but discs most always loosen off. The moral of the story is to always leave you car in gear when you leave it.


Peteff - 7/8/06 at 02:48 PM

It won't make any difference, it's only the compression holding it so it will still turn over forwards or backwarsd if the hill is steep enough, I doubt if the weight of a locost will turn it over though


mcerd1 - 7/8/06 at 03:09 PM

the other type of handbrake for cars with rear discs has a small drum inside the disc (i.e. normal brakes = disc, handbrake = small drum in centre)
I think thats what on the old cavaliers or vectra's (but I could be wrong)

landrovers have a drum on the back of the gearbox as a parking brake (it gets a mechanical advantage that way)


indykid - 7/8/06 at 03:53 PM

quote:
Originally posted by mcerd1
landrovers have a drum on the back of the gearbox as a parking brake (it gets a mechanical advantage that way)


it might get a mechanical advantage, but they're still crap!

i don't trust the lurch as the backlash gets taken up in the diffs with transmission brakes. and even then, you're never sure if it'll hold. most unnerving.

there just seems to be a better and better case for having drums on the back of a locost. i would say that though

tom(with drum braked indy)


cloudy - 7/8/06 at 04:28 PM

quote:
Originally posted by Avoneer
Put it in 5th gear then!

I always leave my car in gear.

Makes it harder to steal as well if they want to drag it onto a trailer after cutting the handbrake cables.

Pat...


remember the force is coming through the gearbox backwards, meaning 1st is the highest ratio - using 5th is a bad idea, it gives the most mechanical advantage against the engine....


DIY Si - 7/8/06 at 05:06 PM

You could always just take a brick with you.....


2Fast - 7/8/06 at 05:39 PM

quote:
Originally posted by cloudy
quote:
Originally posted by Avoneer
Put it in 5th gear then!

I always leave my car in gear.

Makes it harder to steal as well if they want to drag it onto a trailer after cutting the handbrake cables.

Pat...


remember the force is coming through the gearbox backwards, meaning 1st is the highest ratio - using 5th is a bad idea, it gives the most mechanical advantage against the engine....

I would have to agree with Cloudy here, 5th is a 1/1 ratio on a lot of cars whereas 1st is lower and would therefor need more effort to turn the engine.

I find with my MR2 that pulling the handbrake up one more notch than usual on a hill holds it rock solid (handbrake grabs rear disc), my driveway is on a steep incline and even after a good thrash and half an hour wait i can push on the car and it'll stay solid, i tend to leave it in first though just in case.


MikeRJ - 7/8/06 at 06:45 PM

quote:
Originally posted by mcerd1
the other type of handbrake for cars with rear discs has a small drum inside the disc (i.e. normal brakes = disc, handbrake = small drum in centre)
I think thats what on the old cavaliers or vectra's (but I could be wrong)


The Astra GTE and Cavalier SRi's both used this system, very effective it was too IME. However, I suspect there must have been a weight penalty for having two entirely separate braking systems.


r3nuf - 7/8/06 at 07:32 PM

Colleagues newish M3 Convertible did the same.

Caused a few quid's worth of damage to his car and neighbours.

This was a couple of weeks before it got nicked off his drive! Poor bugger.


Liam - 7/8/06 at 07:35 PM

quote:
Originally posted by MikeRJ
quote:
Originally posted by mcerd1
the other type of handbrake for cars with rear discs has a small drum inside the disc (i.e. normal brakes = disc, handbrake = small drum in centre)
I think thats what on the old cavaliers or vectra's (but I could be wrong)


The Astra GTE and Cavalier SRi's both used this system, very effective it was too IME. However, I suspect there must have been a weight penalty for having two entirely separate braking systems.


Ah haaaa!!

Of course - that's why my Omega has a little drum handbrake mechanism sort of in the rear disc bells. Absolute geniuses! I'll never knock it again... unless I ever have to work on it again that is...

Liam


John Bonnett - 7/8/06 at 07:35 PM

I had a car run away once down a steep driveway into the road. Fortunately no damage but ever since then I always always always park in first gear with the handbrake on.

John


DIY Si - 7/8/06 at 07:45 PM

I had my van do it on a customer's drive once whilst I was sat on her drive! Thankfully it's only a transit connect so I could wedge my foot under the front wheel and stop it. Only realised when I heard a creak and a movement out of the corner of my eye.


Jeffers_S13 - 8/8/06 at 09:10 AM

quote:
Originally posted by NS Dev
ahhh hilly sheffield!!

Was up there this weekend funnily enough. Popped up to derwent ressy with my girlfriend and there were a few dax rushes around up there, anybody on here?


There was a Rush owners outing at the weekend, could have been them, how good a look did you get ? was one of them maroon coloured with grey interior ? if so thats Peter Woolvins, the midlands Rep, he usually organises these events, top bloke, I was doing finishing touches to mine !


mcerd1 - 9/8/06 at 08:13 AM

quote:
Originally posted by indykid
quote:
Originally posted by mcerd1
landrovers have a drum on the back of the gearbox as a parking brake (it gets a mechanical advantage that way)


it might get a mechanical advantage, but they're still crap!

i don't trust the lurch as the backlash gets taken up in the diffs with transmission brakes. and even then, you're never sure if it'll hold. most unnerving.


I know exactly what you mean

try putting it on at before you've stopped (1 or 2 mph) the mechanical advantage means 1 click and the wheels lock - then the whole thing bounces back and forward within the backlash for a couple of mins

its a good parking brake, but you just need to remember to park 6" up hill from anything it might hit


PaulBuz - 9/8/06 at 06:44 PM

Surely the amount that disk shrinks in its thickness is negligible.
I would have thought that the stretch in the tight handbrake cable would easily be able to absorb that small amount.
................Obviously I'm wrong - but its what I would have expected!!