What would cause...

ste_bla · 18 Jul 2008 at 20:45

Under heavy braking from high speed the back end jumps/squirms around. Mainly contry lanes although its fine the other car (same model but different engine)

What/where should I start looking at?

i was thinking brakes however they seem fine at lower speeds/lighter braking

Tinders · 18 Jul 2008 at 20:53

Bushes,rear arms and rear antiroll bar bushes would be worth checking.

Gaygle · 18 Jul 2008 at 21:07

What tyres have you got on the rear and what car is it? Cars squirm around by nature under heavy braking (in cars with a front mounted engine) as all the weight of the car is transferred to the front, leaving very little to keep the rear wheels firmly on the floor, hence making the back end go light.

BigglesPiP · 18 Jul 2008 at 21:08

Standard wheels?

Offset at the front can cause this.

FrannoBaz · 18 Jul 2008 at 21:08

Tracking?

ste_bla · 18 Jul 2008 at 21:18

Tryes are goodyears (not sure which as only got today), the other (nearly identical car) has some I've never heard of so doubt its that.

Standard alloys

I'll put it in the air tomorrow and have a look at the bushes etc

LewisStuart · 18 Jul 2008 at 21:26

Worn suspension?

MrMatteh · 19 Jul 2008 at 00:45

LOOS?

check the brake bias

zeppelin101 · 19 Jul 2008 at 00:46

I'd say it's most likely to be rear tires or bushes.

Mileage? What sort of driving do you?

ste_bla · 19 Jul 2008 at 00:55

zeppelin101 said:
I'd say it's most likely to be rear tires or bushes.

Mileage? What sort of driving do you?

97k I think, this car no driving yet (well 20 miles from collecting + petrol)

Zuban · 19 Jul 2008 at 00:55

ste_bla said:
Under heavy braking from high speed the back end jumps/squirms around. Mainly contry lanes although its fine the other car (same model but different engine)

What/where should I start looking at?

i was thinking brakes however they seem fine at lower speeds/lighter braking

is it something that started suddenly or progressivly?

and is the squirm consistent, as in does it initally pull in one initial direction when you apply the brakes?.

ste_bla · 19 Jul 2008 at 01:00

Zuban said:
is it something that started suddenly or progressivly?

and is the squirm consistent, as in does it initally pull in one initial direction when you apply the brakes?.

Just got the car and driven 20 miles in so unsure and it doesn't really pull to either side I can feel it squirming though

zeppelin101 · 19 Jul 2008 at 01:03

I'd see if you can find somewhere to test it, but definitely check the rear tires first as a starting point.

Zuban · 19 Jul 2008 at 01:08

ste_bla said:
Just got the car and driven 20 miles in so unsure and it doesn't really pull to either side I can feel it squirming though

yeah sounds more like bushes/tyres to me, if it was a dodgy caliper/pad it would likely pull more to one side.

Vasquez · 19 Jul 2008 at 01:10

tyres can be a bit slippy when new could be that.

viper_2003 · 19 Jul 2008 at 09:45

Just a characteristic of the car? The weight transfer under heavy breaking could just be unsettling the rear, most cars do it to some extent.

ste_bla · 19 Jul 2008 at 09:53

viper_2003 said:
Just a characteristic of the car? The weight transfer under heavy breaking could just be unsettling the rear, most cars do it to some extent.

No.

I have two (well three but..) one I have had for ages with crap tyres doesnt do this, this new (to me) car does this and it has decent tyres. They are the same model of car but different engines both RWD and they weigh within 50kg of each other.