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Slow speed clacking noise

Alex L

Alex L

PCGB Member
Member
Really weird this one and seems to be baffling everyone. Between about 5 and 15mph, when my car is warmed up, I get a intermittent clacking noise.

The noise is more frequent the higher the speed but less loud, and less frequent at slower speeds but louder. Happens on smooth or rough surfaces equally.

It's like something is catching then releasing and causing a noise relative to the friction & inertia to overcome it.

This doesn't happen when the car is cold or at standstill. It happens with the clutch in or out, or not in gear so it's not rev/gear related.

Perhaps it's the brakes sticking?! It seems to be coming from the rear of the car.

Anyone has anything like this before? Any ideas what it could be?

Many thanks,

Alex
 
Alex,

I would start with the rear brakes. Could be pad knock or a stone lodged in the top of the caliper or rotor vane.

Good luck with solving this. [:)]

Clive.
 
Alex

I'm with Clive on his advice but just to throw something so basic into the discussion that you may have overlooked it - have you checked the tyres for stones, nails etc?
 
Good suggestions guys. I am getting the car up on my OPC's ramp tomorrow to take a closer look.
 
The clacking rate is about:

5mph = 1 per 4 secs (loudest)
10 mph = 1 per 2 secs
15mph = 1 per 1 sec (quietest)

So that's quite a lot of revolutions of the wheel per 'clack'. I can definitely feel it sticking and then releasing (with the noise), whatever it is.
 
Is it a drive shaft or CV joint being unhappy??
Mine used to make a small amount when on full lock..

garyw
 
Well it makes the noise if I am braking or not - so I dont think its brakes related now. Will mention the DS/CVJ tomorrow, thanks.
 
Hi Alex,

I was thinking exactly what Clive suggests as I had similar on my Cayman.

It was hard to identify an exact location and was more of a regular 'ticking' to be honest, got quicker when I speeded up and did it whether braking or not.

Mine was as simple as a small road chipping which had lodged between the top of the rear nearside calliper and the disc and was catching on the disc face. Really difficult to see, but with the wheel off and a torch, I could just see it stuck there. Getting it out should have been easy, but I tried to flick it out and it dropped into the depths of the calliper, so I had to take the calliper off.

Located it again, being blase, flicked it out again and it dropped into the hub casting. Poking with wire, eventually got it out and everything was fine from then on.

Hope it's somehing as simple as that on yours Alex and would be interested to hear of the resolution.

Regards.

Barry.
 
OPC couldnt find anything. I am booked in for a full day diagnostics in a couple of weeks.

They suggested in the meantime I have a chat with Chris from CG to see if it could be suspension related (which I dont see how it could be given it happens on perfectly smooth surfaces going at 5mph whether in a straight line or turning).
 
Alex,

If it's not one of the more common issues already discussed, it may be something like a bent rim or disc shield, but this would normally be indicated by some sort of abrasion.

You may need to run the car suspended and raised on a ramp to identify its location (it's 4WD don't forget! [&:]), I expect this is what the OPC is intending to do, but I'm surprised they can't do it for a fortnight. [:mad:]

Regards,

Clive.
 
Hi Clive

The OPC kindly booked me in early for a quick diagnosis to check that it wasnt anything falling off and thereby dangerous. My main booking as I say is in a couple of weeks.

Yes I think the OPCs best bet for diagnosis is to put the car up on a ramp and then leave the wheels turning in 1st gear (I know they often do this).

If it were wheel related though wouldnt I get this noise every single rotation? 5mph every 100 yards or so is much more than a single wheel rotation. I can feel something catching and releasing - so it must be something brakes or drive-train related.
 
Alex,

If it's something grabbing it probably is brake related - maybe the handbrake.

If I remember correctly your handbrake works with brake shoes acting on a drum, an integral part of the brake rotor. This has an auto-adjust mechanism which sometimes goes wrong. This is another area to look at but, as with all these things, it's difficult to diagnose from afar.

Would be interested to hear once you've resolved it though.

Regards,

Clive.
 
I wonder if it's an ABS fault? Although I guess that would bring up a warning on the dash. Or maybe the PSM is grabbing one or more of the brakes when it shouldn't? Odd one. Do the brakes/wheels feel or smell hotter than normal after drive?
Wheel bearing possibly?
 
Sadly not. OPC had the car all this week and couldn't diagnose it.

When I took the car in last weekend and I was reverse parking it into a spot, I pushed the brake too hard and came to an abrupt halt. There was then a big clack noise 10 times louder than rolling forwards.

OPC thought it might be the driveshaft but without ordering a new one and swooping it there was nothing they could do.

So I have arranged some time with Chris at Center Gravity to see if he can do any better. So hopefully will know more towards the end of the month.
 
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