Chris Lang

My car has done 11K and when reversing on a right hand lock out of parking spaces has developed a "clunck" which repeats itself a few times. It sounds much louder than a CV joint, almost if the transmission is sticking on the front left wheel.

Is this some form of "transmission wind up" or something else?

The problem is getting worse. There is no noise when going forwards.

Darren Thompson

It could the back diff there have been a few threads on this and I think there was one in Drivetrain yesterday.

In fact I have been off and got the thread for you.

crusher

Could be that part of the rear suspension is fouling when in reverse....look just a fer inches forward of the rear wheels and you'll see a flat bracket (approx where the rear jacking point on the body is)...the mounted arm above it moves upwards as you go forwards and downwards as you go backwards....if you've had the car jacked up there(for instance by a tyre fitter with a trolley jack0..this mounting can be distorted and lead to a knock when reversing....tends to be worse when on lock....

MarkF

Chris, my 93 WRX does exactly the same! I and a couple of friends who are mechanics have come to the conclusion that it is the cv joint starting to go. I haven't had time to look at it properly yet but it may be in need of regreasing. Also I have a slight vibration when doing 60mph. It feels like a wheel vibration but all 4 wheels have been balanced and i'm pretty sure its not the clutch.

steve McCulloch

Blimey - you can reverse - my car hates this - always has - and the clutch always stinks whenever in reverse mode - and no I am being very sensible and not letting it slip

My car makes loud knocking noises occasionally - but this is from the engine when I cant get it started on very cold mornings!

ski

Chris
My car does the same,its a MY00,with standard alloys and suspension.About 6k on the clock.Could it be steering rack and track rod ends?
ski.

SimonH

Er, hello...mines been doing exactly the same thing (MY00, 6000m, spooky).
Think I'll be visiting Monsieur Le Subaru Servicing man tomorrow.....he can tighten up my front spoiler as well which rattles like, well, rattles a lot.

nigelm

I thought I had a puncture when reversing on full right lock when I heard a clunk, sounded like alloy wheel on ground but all normal. MY99 43K what's going on?

mattski

mine does it too!

only when reversing right out of a car parking space (there is a slight 'lip' in works car park).

My clunk/knock only does it once and is fairly subtle but loud enough to be noticed...

ta,
Matt

(MY94 WRX)

[This message has been edited by mattski (edited 18 January 2001).]

Chris Lang

Following on from my original post, the car has never been jacked up, except at sevice by a main dealer.

It is definately coming from the front of the car and only on right hand lock one way.

It is in to be looked at in a few weeks - I will let you know the results.

On another point how can I change my user profile details?

Moss

Similar problem (as discused in Drivetrain). Went out to see if it's worse to the right and sure enough it is!? Mines more of a "geary" type grinding though.

Top of page, click on 'profile' to change details.

Moss

TKH

This can often be tracked down to front brake pad pins moving in the caliper when there not hot try to wiggle them you'll be surprised at the free play.

or

if you have a wrx with adjustable diff make sure its rolled full back as even one notch forward can bring on some evil noises on lock.

Tim

Luis

I had this problem on MY97 and it started developing on my new MY00 already. In both cases it was tracked down to front brake pads, just like TKH mentioned.

robski

Me too, just started doing it
I too thought it was alloy hitting low kerb as I drive out of my drive.

Only been doing it since last service!

robski

NITO

Guys,

I back what TKH and Luis said. It's the brake pads in the calipers so nothing to worry about.

It happens particularly after a hard thrash wear sometimes the pads haven't had a chance to cool and create hot spots over the disc when they are stationary. I once went for a thrash and left the car for about a week...next time I came back to it it just wouldn't reverse...they'd literally welded themselves to the discs...eventually with a bit more revs they released with an almighty klunk.

Other times when you are braking to a stop the pads can shift minutely forward as they grip the discs...when you go in reverse they go back to their positions particularly when you brake in reverse or touch the pedal!

I think this happens more with the 4 pots IIRC as I don't remember it happening on my old brakes!

Nito

Chris Lang

I have been re testing the knock today and it is only there when the car is cold in the moring or having been parked in the day. If it has been driven hard there is no knock at all.

In addition, there are a number of knocks when you go backwards so I presume this rules out the pads going back into position?

TKH

I dont think you need to worry too much and it actually makes more sense now because if you think about it after a hard drive the pad pins would expand at a far greater rate than the calipers and so would go tighter in the holes thus reducing the free play and the resulting noises and then on cooling i.e first thing in the morning they will have shrunk back to normal size bringing back the clunk until heated up again.

Chris L

Chris

I have exactly the same thing on my MY00. I only get it when reversing out of my parking space (in the morning, when it's cold) and I have to put the car on full right hand lock. I get a series of knocks, sounds like they come from the back of the car.

I don't think it is the rear diff as mentioned in the thread posted by Darren. It is a distinct knocking noise, rather than a grinding noise.

I'm seeing Steve Lawson tomorrow (ex-Subaru guy) - I'll see what he says.

Cheers

Chris

[This message has been edited by Chris L (edited 19 January 2001).]

Bob Rawle

Gents, this is not down to brakes etc but most likely the tyres digging into the drive/road surface and then skipping causing the "knock". I've actually witnessed a tyre trying to wind itself off the rim when reversing on full lock, at a trackday with slicks a car had a tyre pull itself virtually off the rim altogether due to the extra grip. So reverse out and don't hold full lock all the time, when everything is warmer (tyres etc) its not so prevailant. My car does it is well and its definately the tyre skipping as it digs in, no problem as they say.

Chris L

Interesting post from Bob and it sounds quite likely, except that I have experienced this knocking when reversing out of my parking space, which is on a slight slope, so I normally reverse out in neutral - i.e. with no drive. I did speak to Steve Lawson about this today and he did say that the cause WAS normally the brakes. I'll see if I can get him to post an explanation. He didn't think it was a problem, but if you are concerned I would recommend you go and see your dealer.

I would never question Bob's undoubted tuning talents with the Impreza, so I've no reason to doubt his reply concerning this issue either, but Steve knows these cars as well as anyone in the UK, so it will be worth getting his input too.

Cheers
Chris

Bob Rawle

What I am describing occurs every time I reverse from my garage and it repeats for as long as I have full lock on, I know its the tyre jumping cos I have a big hole in the gravel were it happens, brakes can do this of course but then would usually just give one knock per pad set, so two scenarios both can happen, Steve should know of maybe other causes as well, my AP's do this if the car has been stood out but never if its in the garage.

BTW a big thanks to Steve for sorting out my new turbo, downpipe, roll bars, anti lift kit, drop links, transmission fluids last Thursday at Scoobysport, everything done methodically, professionaly and right first time.