Technical identifying a clonk from below..

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Technical identifying a clonk from below..

Slowco

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HI everyone,
Ive been living with a 'clonk' sound from below for a while now, although now its becoming a bit more prominent and worrisome! its 2013 panda 4x4 twinair. it drives well, and nothing feels wrong with the handling or otherwise.

Its related to suspension, so sounds on any bumps in the road. it sounds like a loose, heavy ish component being knocked into something adjacent.

I had assumed it was the exhaust flexi hanger letting the exhaust pipe hit something, but after ive been underneath and checked everything over veryt thoroughly, ive come up empty. Ive checked every nut bolt, ball joint, spring, bush i could get my hands/socket onto underneath and cant see anything amiss. all tight. while driving, it sounds approximately to come from below the gearstick area. the front ball joints are all solid and no knocking. access to down below through the engine is v difficult and crampt (im used to working on a 1984 transporter, so loads of room in the engine bay to work in!), and so i cane feel anything loose in there either.

the eld works as normal. the propshaft feels good, has a *tiny ammount of play but i suppose thats normal. as i say, it happens over bumps and vibrations.

thought id ask if there was anything familiar about this- weve only had it since december, so pretty new to the car.

thanks all!!

john
 
Sounds like the front anti roll bar drops links.
They bolt to the suspension stut and connect to the roll bar, look like a small bar with a ball joint either end.
They are notorious for wearing on nearly every car.

When they wear badly they can sound like something really bad under there is loose and as the roll bar is conected to the other wheel on the axle, the clonk can transmit across the front of the car.

They are difficult to test.
If you jack up the wheel, the weight of the wheel pulls all the slack out of them and they seem fine.
Sometimes you can slide under and grab hold of them with your hand and rattle them when the road wheels are level and straight ahead.
They should feel really tight, if they floppy or loose, there's your culprit.

Best change both sides, they are only a few quid each and are pretty simple to fit.
 
oh interesting, thanks for the reply :)

yes i know wexactly what youre describing.. and correct, the weight of the car nips them all up snug.. hmm. ill definitely check them over. you say they do have ball joints on them, and not rubber bushings, so they could make the metal on metal sound, i suppose.

I wish the panda had a haynes manual available :(
 
Very likely to be the drop links (they are 'sacrificial' -- and cheap -- and need replacement after 30-50,000 miles - depends on how hard you hit speed bumps!). But, you might also check the ‘dog bone’ bracket that is at the rear of the gearbox and connects to the subframe, quite close to the front end of the propshaft. The rubber bushes in this aluminium casting (that is bone shaped) fail with time, leading to a metal-on-metal contact. There was a recent post about this… here: https://www.fiatforum.com/threads/rear-engine-mount.494204/ have a read through...
 
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Very likely to be the drop links (they are 'sacrificial' -- and cheap -- and need replacement after 30-50,000 miles - depends on how hard you hit speed bumps!). But, you might also check the ‘dog bone’ bracket that is at the rear of the gearbox and connects to the subframe, quite close to the front end of the propshaft. The rubber bushes in this aluminium casting (that is bone shaped) fail with time, leading to a metal-on-metal contact. There was a recent post about this… here: https://www.fiatforum.com/threads/rear-engine-mount.494204/ have a read through...

thats awesome thanks. we do love at the end of a rough track, so yes hopefully this will be the problem. have a to squeeze in a time to crawl back under and sort it. cheers all :)
 
As has been mentioned, tricky to test drop links as weight of car on them, or weight is suspension hanging when jacked up both put load on the drop link ball joints.

The trick is to jack the car and take a wheel off, then use a second small jack to just lift the lower wishbone slightly. If you then take hold of the drop link it should be stiff to turn the ball joints at either end if it. (Likely too stiff to turn by hand). If the joints are worn, they will swivel very easily and may even feel ‘sloppy’. You may need to adjust that second jack up/down a smidge to get this right.

If worn, they are easy to remove and replace - I’ll find a link to an earlier post that shows how.
 
success!
i found 2 drop links on ebay, febi bilsteins for about £22 the pair. I had to cut off the top end retaining nut because of a stripped allen socket in the stud (my fault probably, i didnt clean the threads properly and it was pretty stuck on) but getting the new one back on was pretty straight forward (lowering the suspension onto a wooden block until the holes lined up). there was a small ammount of slop (maybe 1 and a bit mm) in the old one (bottom joint), which seems to have been causing all the clonking cause its all quiet now.

IMG_20220630_210710.jpg


this 2013 car is somewhat easier than our 1984 van for moving stuck nuts :) everything is so much smaller too.

Ive only changed the left side- we're taking it away this weekend so ill do the other side when we get back. so thanks everyone for your advice- you were all on the money :)

cheers all!
 
just to round this off, these two photos of the same drop link are of each end. You can clearly see its just water ingress that has degraded the balljoint- the other end is mint condition. So they may not be infact wear items so much, more that they just fail when water gets in and rusts them out.


IMG_20220704_152731.jpg

IMG_20220704_152719.jpg
 
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