Help! (please! )

Bit of a strange one this

The problem is an intermittent clonking noise under braking, sounds like it's coming from the front of the car and varies seemingly for no reason. Sometimes I can complete a whole journey without any noise yet this evening under hard braking 80mph - 0 it sounded like the car was going to fall appart!! It then completed the rest of the journey without a whisper.

It's a UK98, no changes to suspension with Godspeed 308mm grooved and drilled disks and 4 pot's on the front.

There's no noise just rolling along, we've tried accelerating quickly (as yer do ) and cornering hard (enough to get the husband to tell me off ) and that doesn't seem to reproduce the problem Since our last service the problem seems to have got a quite a bit worse.

I'd appreciate any advice for basic things to check before we have to take it in anywhere...

Thanks in advance

Jen

 

Take your high heels off

 

LOL @ Sonic

I've noticed the same on my car (front & rear). Could be the pads moving in the calipers. I have the Godspeed 335 fronts & rear discs/pads.

Stefan

 

lol @ Sonic!

...being 5ft 11" and the balance of a drunk monkey I tend to have a few problems if I wear high heels

Don't think it's the pads rattling as I've heard them before - today was *seriously* loud as well...but I'll definatly double check tomorrow Thanks!

 

its yer abs.

 

so is it just a single clonk as you brake or a constant banging whilst you're applying the brakes?

Stefan

 

I sometimes get a strange noise under heavy braking on my car, havent quite worked out what it is myself, its more like a grinding noise as apposed to a clonking noise tho

 

Stefan - it's a constant banging (one of those "it's going to be expensive" noises ), sounds kinda like it's everytime the wheel goes around, but seemingly too far apart for that (sorry, not the most techincal person in the world! ). Hope that makes sense.

Bart - I did think that, but the braking isn't that heavy! Thanks.

 

could be a wheel bearing or CV joint. Neither are the cheapest of things

Check for play in the driveshafts and have a wobble of the wheels when they're jacked up...

 

Mm, there's also a bit of creaking when you turn the wheels sometimes...i.e. when manouvering (sp?!) into the garage...would that be another clue?

Thanks David - I'll try jacking it up tomorrow btw [stupid mode]what's the CV joint?[/stupid mode] - yeah, I do feel silly asking!

 

CV joint = Constant Velocity joint. They're the things that are on either end of the driveshafts - wrapped up in rubber boots.
They connect the driveshaft to the wheel and to the diff.

No idea about the grinding noise.

 

Thanks matey

Sonic, it's not a bit of grit or something? or is that far to obvious

 

If it was grit or debris between the pad and disk it would normally make more of a squeal or screaching sound than a 'expensive' clunk. Check the surface of the disc for markings or scoring. Does the noise vary under light or heavy braking?

I was told that I'd know when a wheel bearing had failed as they make a horendous groaning noise all the time and not just under braking.

If you had something wrong with the CV joint, diffs or the bearings I'd expect more clonks during everyday driving and not just under braking.

Other possibilities are the suspension components which are stressed as the car dives under braking. Again, that should be easily replicated under hard driving - accelerating, cornering, etc..

Can you narrow down where the noise is coming from - either one side of the car or the other, both or more in the centre underneath

Stefan

 

My wagon does the same **** as jens and it don't sound good, mine has got to the point of clicking all the time when i drive and making a bang when i brake. CV joint, I say, give it time and let it pop out totally and change it at the side of the road.

 

Yeah - sorry Stefan, I meant Sonic's grinding noise for the grit, although I reckon he'd have already thought of that

I'll try and analyse it a bit more on the way to work this morning

Legacy - I'd like to do that! lol! although it would just involve me stood by the side of the road with a confused look on my face

 

Ok - had a good blast down my favourite country lane on the way to work - lots of left and right handers and I did my best to put the car under as much load as I could handle when driving No noise until I came to brake and then a loud droning decreasing to clonking getting progressivly slower as my speed reduced.

Chris reckoned it was coming from his side of the car, and I reckoned it was from the drivers side, so I guess that's both

Spent about 5 minutes doing circles in the IBM car park - there's a slight noise on full lock "left-hand-down" going both forwards and backwards but it doesn't seem to be the same as the clonking noise. "right-hand-down" all seems normal.

Harsh acceleration - no noise.

We thought we heard a very faint clonking a couple of times just driving along, but tbh that could just be our imaginations - paranoia is a great thing

And again - sometimes no noise under braking - does seem to be intermittent....

Not sure if that makes things any clearer?! If it doesn't - thinking of taking it to Rally Colin, anyone any comments?

Thanks

Jen

 

Jen, the noise under full lock is just the power steering "hissing"

 

No it's not muppet boy. After I dropped you off I went into one of the other car parks and there was def. a noise under "left-hand down" that wasn't there under "right-hand-down"...didn't sound the same though so I don't think that's part of the problem...probably would have never noticed it if I wasn't listening for it....

 

Hi Jen

ohh i love a good clonk!!!

to test for cv joints...

drive in a slowly decreasing circle either l or R


if the joint is ok it will be all quiet..

a clonk or knoking sound on lock under driving load is a sure sign of joint failure...

with regards to the braking clonk,,, check the back end!!! its amazing how sounds can travel... also check your coil springs!!!

a broken one of these can give similar results... it could also
a roll bar or a suspension/ steering component wearing out...

if it is a contact based clonk examine wheel rims interior & exterior and as a final thought it could possibly be a wheel bearing starting....

hope this lot helps


Mart

 

Thanks Mart, will spend this afternoon looking for strange things under the scoob ...in fact, I'll print this out so I don't forget anything!

 

good luck! I've chased a clonking noise round my Scoob for nearly a year now... It's very intermittent now, so I'm (foolishly) going to ignore it!

 

Hi Jen,
Sounds like a CV joint to me , have you tried full-lock left and right in the car park. This produced the noise you describe on one of my previous cars. Hope it's nothing too expensive .

Jay

 

Thanks Jay, I'll bear it in mind - there's no noise under full lock, just under braking

I've still no idea, but I intend to check all these out

Thanks for all your help guys

 

and the clonking continues

i like staying power!!

have you checked that the caliper bolts/ disks wheel nuts are tight...

stranger things have happened...

also get someone to sit in the car and apply the brakes then rock the car back and forward ... you may see or be able to detect the clonk from outside...


mart

 

Hi Jen,
You need to check all the caliper and bracket nut's and bolts, and, I know it sounds silly, but are the pads in good nik?? you may even be rubbing the pads on the disc bell, (the ally bit!) if it's only under braking, it's gota be brake related, so get it checked out, cos brakes matter!!!
One of the little bolts that hold the disc to the bell has fallen off of my car, so get it all looked at.

Ron.

 

I agree with Ron, although I'm far from being an expert. Correct me if I'm wrong but the braking system is pretty straightforward. Brake pedal, master cycliner, brake lines, calipers, discs and pads (have I missed something).

If it's only making a single clonk under braking then I would look at the caliper and brake pads for excess movement. If it's banging away whilst your braking, then it would suggest to me that something's banging as the wheel or brake disc rotates.

Strap Chris to the bonnet and get him to listen more carefully

Stefan

 

take it in to a dealers or something cause if your brakes go you could do yourself some damage,and we dont want that now do we? and dont forget to let us all know what it was cause i for one is very puzzled now...

 

mine also does this
checked the caliper bolts today and noticed they werent too tight.
They needed another 2 or 3 turns.
Havnt tested yet but i guess this is the clonking noise as the calipers must move slightly when the brakes are applied.

Ill know when i next drive it!

 

you mean you didn't go straight out and test it? lol shame on you,you dont go by the rule of any excuse for a drive

BM

 

that fixed it!
try your caliper bolts?