Technical Odd knocking noise with road speed

[bigshorty]

Hi All

Wondering if someone can help identify a knocking noise that has occurred from my 2004 Panda 1.2 Dynamic Dualogic on 48000 miles.

The noise sounds like a knocking / thudding sound from the front end, offside I think. It happens when I first start driving the car from cold, and the knocks speed up and slow down in relation to road speed. I can also feel each thud / knock through the throttle pedal. After about a miles worth of driving the noise goes away, and the car seems fine. The car only went for an MOT a couple of days ago, and I was convinced this might show up what the problem was, thinking it could have been a driveshaft, CV joint, suspension, brakes, or something like that, however it passed the MOT with no advisories. I can't see anything out of place, so am at a real loss as to why this noise should be happening.

I have done a bit of research, but can't find anything that relates to this issue. If anyone has got any views, thoughts or comments on this and what could be causing this noise, I'd be very grateful to hear them.

Many thanks in advance.

 

[koalar]

If you can feel it through the pedal it needs sorting immediately.


First check your wheel nuts

Next check the wheel bearings. Tried to find a decent video and failed.

But you get the idea from here

 

[bigshorty]

Thanks for the reply, the possible causes you mention are my thoughts as to what could be causing the problem.

However, I didn't know if this extra bit of information might be significant. I know that the dualogic transmission can be jerky when changing gear, but do you know if you should be hearing a slight mechanical sound when it actually changes gear? I've not owned the car for long, and never driven an automatic before, so didn't know if this was normal, and if not, whether this could be a reason for the knocking.

 

[varesecrazy]

Thanks for the reply, the possible causes you mention are my thoughts as to what could be causing the problem.

However, I didn't know if this extra bit of information might be significant. I know that the dualogic transmission can be jerky when changing gear, but do you know if you should be hearing a slight mechanical sound when it actually changes gear? I've not owned the car for long, and never driven an automatic before, so didn't know if this was normal, and if not, whether this could be a reason for the knocking.

hi,
there is "other kit" involved with any clutchless manual.

however once properly engaged in a driving gear ,
there should be NO ROTATING NOISES

as it's then the same as a 5 speed manual in a panda.

ideally we'd need more info on the sound,

at what speeds..? does lightly applying the brakes change the sound..etc

charlie - Oxford

 

[irc]

I know that the dualogic transmission can be jerky when changing gear, but do you know if you should be hearing a slight mechanical sound when it actually changes gear?

Jerky changes may be because you are trying to modulate engine speed at gearchange rather than letting the system do it. The knack takes a little time but then seems "right" and you will do it without realising.

If you listen hard at gearchange time with a window open you can sometimes hear a sound similar to a rifle bolt sound effect from a movie. That is the "robotic" gearchange, which is doing all of the things that a manual change does, just quicker and more accurately.
"Normal" automatics dont make that kind of noise as they work differently.

Other than the actual gearchange (and the occasional buzz from the dualogic pump) any noises made wil have the exact same cause as a manual Panda.

The rotating noise could be loose wheel nuts, wheel bearing, deformed wheel, driveshaft or a number of other things.
Work through the possibilities methodically and post what you find.

 

[bigshorty]

hi,
there is "other kit" involved with any clutchless manual.

however once properly engaged in a driving gear ,
there should be NO ROTATING NOISES

as it's then the same as a 5 speed manual in a panda.

ideally we'd need more info on the sound,

at what speeds..? does lightly applying the brakes change the sound..etc

charlie - Oxford

Thanks for the reply Charlie

Right, I can definitely say there are no rotating noises once the gear has been selected, it is just the engaging of the gear that causes a noise. The noise itself is a rather quiet, metallic clunk / grind type noise and it seems to be a bit more pronounced during the upchange from 2nd to 3rd, although it is there during every upchange. You have to listen really hard to hear it though, and I'm pretty sure downchanges don't make a noise at all.

Does that help at all?

I haven't had the car long, and its only done 48000 miles, however it is a 13 year old car and I'm pretty sure the transmission fluid is the original. I don't know the recommended transmission fluid change interval for dualogic gearboxes, but I'm sure 13 year old fluid can't be a good thing??

 

[portland_bill]

We're getting distracted here by the gearchange noises. Let's return to the important issue of a rotating thumping noise.

This is important and possibly urgent!

First check the wheelnuts.
Next, with one wheel raised, rotate the wheel and feel and listen. The wheel bearing should rotate without any nasty noises.
Any noises, heard or felt need further investigation. Is it in the bearing, CV joint, , inner driveshaft joint, or the diff. May need someone to grovel under the car while the wheel is turned, so ensure car is propped up properly, not just on the car's own jack.
If all that shows nothing, it could be a tyre.

You say you've only had teh car a short time. Prior to your purchase, if it had been sitting unmoved for some time, one or more tyres could have taken on a 'set'. Like bending a piece of paper, you can never make it flat again, there will always be a kink. The tyre will do this every stop, but will recover as soon as driven. If left a long time, the damage could be permanent.

Ideally you now need a tyre inflator to hand. A footpump will do, but will be hard work.
Remove the wheel. Let the air out of the tyre. Once all out, have a good look at the tyre shape. Is it still round? Possibly not.
Now roll it along, applying a little downward pressure. It should roll evenly. If there is any weak part of the sidewall, it should feel different, maybe dropping as you push on it.

Hopefully this will highlight something.

If it is the tyre, it might be a good idea to check them all. Good luck with the footpump!

If tyres are an issue, any weakened area will run hotter, even after it has 'recovered' on each drive. If bought from a dealer, I'd go back to them and ask for four new ones.

Problem, could also be rust on discs. With the wheel off, check the disc surface. Again, if it has stood for some time, there may be more, or less rust where the pads were. This will eventually lead to disc thickness variation, and will cause brake judder. If this is the case, go back and ask for new discs.

 

[varesecrazy]

Hi All

It happens when I first start driving the car from cold, and the knocks speed up and slow down in relation to road speed. I can also feel each thud / knock through the throttle pedal. After about a miles worth of driving the noise goes away, and the car seems fine.

my thought would be the disc on that side is mildly warped.. and it builds a layer of corrosion ( surface rust) which you will scrub off with the rotating over distance.

as portland_bill says it should really be investigated.

warped discs are a fact of life.. and can go years of MOT's without issue.

Charlie

 

[bigshorty]

Cheers for the info and you are correct, we are getting distracted, I just wondered if the the knocking could have been transmission related.

At this point I thought I'd mention that I have just driven the car down the road and there was no knocking noise at all. Incidentally, it's been chucking it down with rain this morning, which makes me wonder if the wet has stopped the knocking. When I took it for a test drive, and when I collected it and subsequent journeys it has been dry. I did notice that when applying the brakes the car was jerking a bit whilst slowing down.

Wheelnuts are fine, but until the rain stops I can't really check each of the wheels for issues with bearings, driveshafts, brakes, etc. But I will definitely go and have a look when the rain eases off.

It was bought from a dealer, and they have given me a warranty with it, so it would make sense to get them to check it over, however I'd like to have an idea of what the problem is before I go back to them, as they could always say they found nothing wrong, especially now the knocking isn't there because of the wet weather.

Some very useful advice there portland_bill, I really appreciate it and will report back my findings once I can get out and have a look. Wish I had a garage!!!

 

[bigshorty]

Just one query, would a warped brake disc really cause knocking that would be felt through the accelerator?

 

[A3jeroen]

CV joint?

gr J

 

[varesecrazy]

Just one query, would a warped brake disc really cause knocking that would be felt through the accelerator?

a mildly warped disc ( that passes an MOT),
will still make the brake pedal pulse..
( the pedals are often all mounted on one bar / rail / structure)

however .. by design the brake pad should only rub for a few seconds with your foot applied.
it should NOT rub for any time / distance.

so if you're well into a journey and haven't used the brakes for over 2 minutes.. it should NOT be brake related.


:idea: do you have access to a trolley jack / axle stands..??

safely raising a corner of the car, and rotating the wheel by hand may just give an indication of where the issue lies.

 

[bigshorty]

a mildly warped disc ( that passes an MOT),
will still make the brake pedal pulse..
( the pedals are often all mounted on one bar / rail / structure)

however .. by design the brake pad should only rub for a few seconds with your foot applied.
it should NOT rub for any time / distance.

so if you're well into a journey and haven't used the brakes for over 2 minutes.. it should NOT be brake related.


:idea: do you have access to a trolley jack / axle stands..??

safely raising a corner of the car, and rotating the wheel by hand may just give an indication of where the issue lies.

Yes I do have access to trolley jack and axle stands, so as soon as the weather eases up I will get out there and have a good look. I've now got plenty of ideas to follow up on, and I'll update with my findings when I've had a good look.

I haven't noticed the brake pedal pulsing at all during braking, but am now wondering if the jerking under braking I noticed was the dualogic changing down gears.

Fingers crossed I'll have an update for you later on today!

 

[bigshorty]

Hi All

Here's an update for you, don't know if someone can come to a conclusion as to what might be causing the knocking.

I raised both nearside and offside front ends and spun each wheel. Nearside sounded fine, offside sounded like there was some rubbing of the brakes, but not constant, just a section of each turn (if that makes sense). Next I checked the wheel bearings and they seemed rock solid on each wheel. I removed each wheel, the nearside one came off quite easily, however the offside one was stuck well onto the centre bore, I needed to give it a good knock to dislodge and remove the wheel. Nearside brake disc looked fine, however offside disc had two noticeable score marks running around the disc. Checked all the components behind the wheels and everything looked solid and as it should, gave various bits a wiggle and didn't notice anything was loose. While each tyre was off I let them down and applied downward pressure to them whilst rolling them along and did not notice and drops or inconsistency in them. So pumped them back up and put them back on. Before lowering each wheel to the ground, I rocked them back and forth and the offside wheel was fine, however I noticed a slight knocking sound when rocking the nearside wheel. Upon further investigation I found the knocking noise coming from the joint where the driveshaft meets the gearbox, I could actually feel the knocking when I put my hand on it and rocked the wheel. I say it was a knocking noise, but it wasn't that loud, more like a loud click.

That's the results of my investigation, if anyone has any thoughts on this then I would be extremely grateful to hear them.

 

[koalar]

offside sounded like there was some rubbing of the brakes, but not constant, just a section of each turn (if that makes sense).

Push the pads back slightly and try again. Push on the tyre while spinning and pull while spinning.


There not much space between the backing plate and disk make sure its not touching.


If the grooves are on the inside edge there could be a stone suck between the backing plate and disk.


There is normally a bit of slop where the drive shaft enters into the diff. Without being there its hard to tell if its normal.

 

[portland_bill]

Just one query, would a warped brake disc really cause knocking that would be felt through the accelerator?

Yes.
Any vibration from suspension will transmit through the car. You will feel this mostly at your feet or hands, as the seat will mask most stuff.

Damage to disc and intermittent rubbing suggest it may be slightly warped or have a thickness variation. As said above, push the pads back away from the disc and rotate the wheel again. The noise will probably not be there. If the pads are not free to move in the carrier they can rub too much, so may need a clean out. Something for the seller to sort.

The slight noise form the LH inner joint is probably nothing to worry about, but worth mentioning to the seller, and let him say so. Then you've a comeback if it gets worse. (Unlikely, but worth having the conversation.

 

[bigshorty]

I really appreciate the replies, thank you.

I agree with your comments regarding the slight noise from the LH inner driveshaft joint, I'm pretty sure I have checked this on other cars I've had in the past, and they have made the same sort of noise.

Now the rain has eased off and the car has dried out, I'm going to take it for another quick run down the road to see if the knocking sound has stayed away or reappeared, that will hopefully eliminate, or maybe confirm that weather conditions contribute to the knocking. I'll then give your brake pad suggestion a go and see what happens. I have to say that it did look like the brake calipers could do with a clean up and a bit of copper greasing, there was noticeable rust present, and I wouldn't be surprised if the pads aren't moving as freely as they should. I've cleaned plenty of calipers in my life so no hardship if I feel like giving it a go.

Cheers again for all your comments and help, and I'll update again as soon as I have any further news.

 

[bigshorty]

Right, next update for you guys, see what you make of this.

I didn't even have to drive down the road to notice the knocking / thudding noise was there again, so is this indicating that the weather is playing a part with the noise?

I took each front wheel off, but couldn't see an easy way of separating the pads from the disc, so couldn't see whether the noise would go away, but the offside roadwheel does grab on during a section of each turn of the wheel. However, I did have a lightbulb moment and didn't know if this had any bearing on what might be causing the noise. I noticed that while reversing out of my parking space, on almost full lock and at very slow speed, I heard an regular, very faint knock or click, which I felt through the steering wheel. Every time the noise happened it felt like there was give in the steering wheel. I don't know if its just me, but the steering doesn't feel quite right when driving along. The best way to describe it is that there is some kind of friction or force every now and again when turning the steering wheel. When I accelerate the steering wheel stays perfectly straight, there doesn't seem to be any pull to either side under braking either. I didn't know if any of this info has given you guys any new ideas of what could be causing the knocking. To me, I'm wondering if a CV joint could be at fault, but if it was why does it knock during dry weather, but not when wet, and why would the noise go away a couple of miles down the road? The MOT was done a week ago, so the CV boot can't be split or perished, as shouldn't be any suspension bushes, etc, as well, so I'm a bit lost now.

Any more thoughts on what could be causing the issue would be more than welcome!

 

[portland_bill]

A CV joint on its way out will usually knock when the steering is on full lock, as that stresses the joint most. Unusual for them to have tight spots when turning, so I'm still with the disc/pads.

You need to push the pads back away from the discs. The caliper sits on a pin at the top, and is retained by a small pin at the bottom, held by an 'R' clip. There is an anti-rattle plate over the pads that keeps pressure on the caliper and therefore on the bottom pin.

It is a single-piston caliper. Grab the piston part and pull towards you, to push the piston back in a little. This should create more clearance for the pads, and the wheel should now turn more easily.
The pads can 'grow' into their carrier due to rusting of the backplates and/or a build-up of brake dust. Find the little 'R' clip, pull it out and drift the bottom pin out. Some pressure of the caliper towards the pads will help. Swing the caliper up, taking care not to strain the hose.
Now you can extract the pads. They should come out easily, but will probably fight. Once out, get a wire brush into the pad carrier, but don't damage the caliper piston seal. The pads may clean up around their edges, or may need replacing. They should be a slightly slack fit into their carrier, only just, so don't attack with a file. If too slack they chatter very annoyingly.
Now repeat on the other side.

Important: Don't forget to pump the pedal to push the pads back to the discs after you've finished, or the first stop may be frightening. (Been there, done that! A long time ago. Stopped about an inch away from embarrassment)

 

[bigshorty]

Thanks for the reply portland_bill

It would make sense that the noise could be caused by the brake pads and/or discs as the wet weather is somehow lubricating them, hence the reason why I can hear and feel the knocking when dry but not in the wet. I can't see any other components that would be influenced by the wet weather before driving the car after it has been parked up. I've just checked the warranty details on my Panda and noticed consumables aren't covered, so it looks like I'm going to have to clean them up myself to try and eliminate the knocking, luckily I'm quite accustomed to messing round with brakes so shouldn't find it too difficult. Just one thing I wanted to ask, do you know why the knocking would disappear after the first mile and a bit of driving?

I appreciate the guide / help, looks like tomorrow is a total wash out, so won't be doing it until middle of the week, but I will update this with the results as soon as I've done it.