Mystery knocking / clunking. Any ideas?

[Arnolfini]

Hi all

Arriving at the car park where I work my car suddenly started producing an odd noise. It's a knocking sound which seems to be coming from somewhere below the drivers footwell (I can feel it vibrating slightly through my feet).

It's a regular rhythmic sound, and seems to make one 'clunk' per rotation of the front wheels, so when driving slowly it slows down, but when picking up speed it goes faster.

Also it's barely audible when driving in a straight line, but gets louder when turning corners - at least when turning right, haven't tried turning left (there are no left turns between the entrance of the car park (when it started) and parking space)!

When I parked up I had a peer underneath, and there's nothing obviously sticking out anywhere, but then again i have absolutely no mechanical knowledge anyway... so has anyone got any ideas what it might be?

I just got new alloys about 3 days ago if that makes any difference...?

Cheers

 

[UncleFester]

I wonder if it's the discs not seated properly?

 

[Arnolfini]

I wonder if it's the discs not seated properly?

Would that be something that could just happen all of a sudden? And would the noise get louder when turning?

When bolting the alloys on the other day, everything looked pretty solid, but like I say, I don't have any mechanical knowledge!

 

[UncleFester]

Are the new wheels bigger / wider than the original ones?

 

[Arnolfini]

Are the new wheels bigger / wider than the original ones?

Yes on both counts - I previously had the standard 16s on there, but upgraded to 18s, and they are slightly wider too.

Also, I just went down to the car park and drove it around to listen to the noise again. It's definitely coming from the front of the car, but it seems to be a little more central than I first said (albeit still more on the drivers side), rather than under the footwell.

 

[UncleFester]

Hmm drive shaft / popped CJ joint cover or a dry joint?

 

[Arnolfini]

They sound scary...

Are those problems expensive to fix?

Also if it's any of those is the car still safe to drive? I'm meant to be doing a 150mile round trip to the airport at about 4am tomorrow!

 

[UncleFester]

Well a quick peek under the car would tell you if a CV boot had come loose ( not an expensive problem to fix) .... i would wait and see what other suggestions come in first though

 

[jonjay]

Cant do any harm following Pats instructions to be honest...I would drive the car in case it was something like that.

 

[Arnolfini]

I have a feeling you might be on to something with the dry joint theory (although I'll get the car jacked up to have a look at the CV boots this evening).

I've just spoken to a mate who actually helped me with putting on the new wheels.... Now said friend enjoys tinkering with cars, and knows a fair bit. He tells me that when the wheels were off he thought one of the joints looked a bit on the dry side.

I take it a dry joint would have the same symptoms that I've mentioned?

Is this an easy problem to solve, and would it be ok to do my airport trip if that's the problem?

 

[UncleFester]

if the joint is just dry, it can be regreased, if the boot has split it can be replaced - a split or worn boot will cause the joint to lose grease and dry out. Dry joints will sound exactly like that.

 

[andycupra]

could be drive shaft catching on something.
i once had a car that had the balance weight on the driveshaft work loose. that only made noise when braking, as the front of the car dropped it caught on something, but then i looked under the car all seemed well as the front was higher.

is the undertray and plastic sheilds in place ok? they could rub on it?

dont suppose the wheels have been on or off recently, new tyres or anything?

*i also agree with the dry comments*

 

[Arnolfini]

if the joint is just dry, it can be regreased, if the boot has split it can be replaced - a split or worn boot will cause the joint to lose grease and dry out. Dry joints will sound exactly like that.

Marvellous! That doesn't sound too bad after all - and my mate's got a grease gun, so hopefully he can regrease it for me next week.

How about my 150 mile round trip tomorrow? Horribly bad idea, or do you reckon it should be ok, so long as i get it sorted ASAP?

 

[UncleFester]

Personally I don't like doing any kind of distance with mechanical noises present, especially if i'm not 100% sure on what is causing them.

Anyone else? lol

 

[Deleted member 20482]

i had a similar noise from my seat when turning corners...ended up changing discs and pads on front and pads on rear.
bye bye noise for me anyway.
dont recall feeling any vibs through footwell though!!!

 

[LiCkWiD]

CV Boot joint.. me thinks. Check for splits in the rubber boot and grease leakage.. first port of call. Turn a full lock and get your hand behind the wheel and feel about.

Edit: Should really read to the bottom of the thread before I post ¬_¬ but there ya go.. further confirmation.

 

[Arnolfini]

Hmmm... Think I'll call out the trusty RAC to come check it out tonight. Hurrah for home start!

 

[Arnolfini]

Turns out it was the wheels!

The numpties who sold me them had sent me the wrong bolts. As such they were working loose, and had got to the point of knocking. A couple had worked so loose that the RAC guy was able to undo them with just his fingers!

Unfortunately, me having zero experience of this type of stuff meant that I didn't realise there was a problem when I was fitting the wheels the other day. I thought the bolts seemed to fit a bit strangely, but just thought that was how they were meant to be...

So my old wheels are back on for the time being, the noise has gone, and I'll be giving the shop i got the wheels from a piece of my mind on Tuesday!

You'd think that an alloy wheel specialist would be able to give you the right bolts - at the end of the day that mistake could have cost me my life!

 

[UncleFester]

Heh that's madness, it's often good to have a poke around - in this case a cheap fix that may well have saved you more than the cost of a set of wheels! Glad you got it fixed!

 

[andycupra]

also check the spigot rings:
see here:

http://www.seatcupra.net/forums/showthread.php?t=43324