Mystery front end knock (clunk) 306

You can put a pry bar between the steering arm (insert from the wheel side going over the steering arm and under the tie rod) and the tie rod and try it lever it up and down to see if the ball joint moves. You might have to turn the steering wheel to get the two in a favourable position, but you don't have to undo or take anything off apart from the wheel. Just make sure the car is solid on whatever you use, jacks, stands, etc. so you don't drop it on yourself (or others).

If you don't want to take the wheel off you could of course try coming from the other side but you'll probably need to turn the wheel at full lock to expose the tie rod/steering arm. The risk is that with the car's weight on the entire suspension you may have to fight higher forces to induce any movement if there is any. Shouldn't be, but at full lock who knows?
 
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schlitzaugen said:
You can put a pry bar between the steering arm (insert from the wheel side going over the steering arm and under the tie rod) and the tie rod and try it lever it up and down to see if the ball joint moves. You might have to turn the steering wheel to get the two in a favourable position, but you don't have to undo or take anything off apart from the wheel. Just make sure the car is solid on whatever you use, jacks, stands, etc. so you don't drop it on yourself (or others).

If you don't want to take the wheel off you could of course try coming from the other side but you'll probably need to turn the wheel at full lock to expose the tie rod/steering arm. The risk is that with the car's weight on the entire suspension you may have to fight higher forces to induce any movement if there is any. Shouldn't be, but at full lock who knows?
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Thank you for this, I had thought of this approach but was worried about the same things. Everything I ever see about testing ball joints seems to be with the wheels off and unweighted. I haven't had the time to fully investigate but I will have to soon as I plan on doing a few driving courses at SMP in the next couple of months. I want the car at 100% for that.
 
BIGRR said:
Check that the nuts on the shock shafts are tight. ?
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I have not. Need to get my tools out of the mother in law's garage. They've been lost in there for months.
 
Finally have had the chance to start investigating this clunk. I have checked strut tops, the bolts at the bottom of the struts, drop links sway bar bushings etc. And all good. Checked engine mount, all ok. Now, just buy chance, with the car on the ground I grabbed the right side drive shaft and it moved laterally at least 5mm and "clunked" every time I moved it. Left side does it too.

So questions - is this movement normal? Or if it's not normal is that indicating either my CV joints are worn or maybe the drive shafts are moving on their splines for some reason?
 
How did you check the drop-links?

My money would be on these. They are often hard to diagnose as they feel fine until there really loaded up. And they the click,clunk into place. Should will have some movement as they need to slide in and out with the arch, about 5mm. Unless the cvs are really worn they wont clunk.

Ive seen many 306 crack the top engine mount area.
 
Hmm, ok then maybe not a drive shaft/cv issue... To check the drop links I literally just looked at the joints and moved the drop links to feel for any strange movement. Nothing looked or felt odd. This is pretty much as far as I can go though... Very hard to diagnose something when you're not sure what's normal!
 
I might order a set of new drop links just to be sure. Where would I order from to get OEM quality parts?
 
Oem will last longer but potentially hard to find. The aftermarket stuff is cheap enough these days to replace them from time to time.
 
cam85 said:
Oem will last longer but potentially hard to find. The aftermarket stuff is cheap enough these days to replace them from time to time.
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Thanks for the info! Hey, this just reminded me I never picked up those parts from you... Covid and second child made last year a blurr....
 
All good. I think they have been moved on as Im about to move to the US and have moved house and shed twice.
 
lowpugV2 said:
Finally have had the chance to start investigating this clunk. I have checked strut tops, the bolts at the bottom of the struts, drop links sway bar bushings etc. And all good. Checked engine mount, all ok. Now, just buy chance, with the car on the ground I grabbed the right side drive shaft and it moved laterally at least 5mm and "clunked" every time I moved it. Left side does it too.

So questions - is this movement normal? Or if it's not normal is that indicating either my CV joints are worn or maybe the drive shafts are moving on their splines for some reason?
Click to expand...

When you say you grabbed the driveshaft, what part do you mean and where did it move? You grabbed the shaft sticking out of the back of the hub and it moved in and out of the hub (with the CV joint)? Or did the shaft move in and out of the outer CV joint? Or did you grab the large diameter part that sticks out of the g'box (inner CV joint) and it moved in and out of the g'box? Any other options I did not cover?

First question, if yes, that's not normal. Check the driveshaft nut on the wheel face of the hub. Is it tight? Can you pull it out/push it in by hand? If yes, no that's not normal, do the nut up. If the nut is done up and staked and it doesn't look like it moved, your wheel bearings are probably about to turn to creme brulee. There is also the possibility there was some spacer/large washer/shim/whatnot someone forgot to install and the bearings are not correctly pinched with the nut done up correctly. Check.

Second question if yes, it's not normal. Your outboard CV joint is not healthy. At best, you lost the circlip that locks the shaft end behind the ball carrier inside the joint. At worst, your entire CV joint is so worn the balls are sliding back and forth. Replace the joint or the entire driveshaft if you can.

Third question if yes, it's kinda normal but shouldn't be able to move it by hand, there should be a definite detent felt and you should need a rather serious tug. If this is it, your inboard joint shaft moves in the outdrive and you need to investigate further why. Usually the driveshaft inboard shaft has a circlip that goes over the (male) splines and locks into a corresponding groove in the outdrive female spline at the g'box. Hence the clear detent if you manage to pull one out (and a clear clunk when you push it back in and the circlip expands back in the female groove). It's supposed to keep the driveshafts from falling out. Maybe you lost the circlip, maybe something is worn or whatnot. They should definitely not come out pulled by hand. At best you need a flat blade screwdriver to lever them out with enough force to compress the circlip. There is a bit of movement there as the circlip is not a tight fit in the groove but not 5mm. Maybe 1-2mm.

Keep in mind, I speak from general experience with other cars, I don't know the 306 specifically but pretty much everything else I've seen is like that, Toyota, Honda, Renault, Hyundai, even other Peugeot models. Hyundai in fact need a fair whack to get them out.

To summarise, none of the driveline components should move laterally (axially?) at all. Something is amiss if they do. They do move in normal operation but only with the suspension compression/extension and the entire movement is taken up inside the inboard CV joint (the joint itself doesn't move). Somehow I don't think you can compress your car's suspension by pulling the driveshafts but if you can, post a video on youtube and we'll call you Hercules.

You didn't mention tie rods, did you check those?
 
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I second sway drop links for odd clunks. Give them a whack with your hand. Sometimes they aren’t done up properly because mechanics tighten the nylock nut till the ball joint starts spinning and don’t realise you need a thin 15mm cone spanner on the axle of that nut to give you resistance to tighten it properly.
 
Mingus said:
I second sway drop links for odd clunks. Give them a whack with your hand. Sometimes they aren’t done up properly because mechanics tighten the nylock nut till the ball joint starts spinning and don’t realise you need a thin 15mm cone spanner on the axle of that nut to give you resistance to tighten it properly.
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Thanks, I can check this. Have plenty of cone spanners in the bicycle tool kit.
 
schlitzaugen said:
When you say you grabbed the driveshaft, what part do you mean and where did it move? You grabbed the shaft sticking out of the back of the hub and it moved in and out of the hub (with the CV joint)? Or did the shaft move in and out of the outer CV joint? Or did you grab the large diameter part that sticks out of the g'box (inner CV joint) and it moved in and out of the g'box? Any other options I did not cover?

First question, if yes, that's not normal. Check the driveshaft nut on the wheel face of the hub. Is it tight? Can you pull it out/push it in by hand? If yes, no that's not normal, do the nut up. If the nut is done up and staked and it doesn't look like it moved, your wheel bearings are probably about to turn to creme brulee. There is also the possibility there was some spacer/large washer/shim/whatnot someone forgot to install and the bearings are not correctly pinched with the nut done up correctly. Check.

Second question if yes, it's not normal. Your outboard CV joint is not healthy. At best, you lost the circlip that locks the shaft end behind the ball carrier inside the joint. At worst, your entire CV joint is so worn the balls are sliding back and forth. Replace the joint or the entire driveshaft if you can.

Third question if yes, it's kinda normal but shouldn't be able to move it by hand, there should be a definite detent felt and you should need a rather serious tug. If this is it, your inboard joint shaft moves in the outdrive and you need to investigate further why. Usually the driveshaft inboard shaft has a circlip that goes over the (male) splines and locks into a corresponding groove in the outdrive female spline at the g'box. Hence the clear detent if you manage to pull one out (and a clear clunk when you push it back in and the circlip expands back in the female groove). It's supposed to keep the driveshafts from falling out. Maybe you lost the circlip, maybe something is worn or whatnot. They should definitely not come out pulled by hand. At best you need a flat blade screwdriver to lever them out with enough force to compress the circlip. There is a bit of movement there as the circlip is not a tight fit in the groove but not 5mm. Maybe 1-2mm.

Keep in mind, I speak from general experience with other cars, I don't know the 306 specifically but pretty much everything else I've seen is like that, Toyota, Honda, Renault, Hyundai, even other Peugeot models. Hyundai in fact need a fair whack to get them out.

To summarise, none of the driveline components should move laterally (axially?) at all. Something is amiss if they do. They do move in normal operation but only with the suspension compression/extension and the entire movement is taken up inside the inboard CV joint (the joint itself doesn't move). Somehow I don't think you can compress your car's suspension by pulling the driveshafts but if you can, post a video on youtube and we'll call you Hercules.

You didn't mention tie rods, did you check those?
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Thanks for all this. It's going up on a hoist very soon. The lateral movement in the outer driveshafts may very well be normal to compensate for various steering angle plus suspension movement. I have a spare set of known good CVs to compare mine to now.

Whatever the issue is it is getting worse. Had to drive the car and it's mostly fine, but the steering does feel somewhat looser than before all this started. And the clunks are now almost every turn of the wheel.
 
Modern drop links have a torx recess in the bolt end to hold it steady. You put a torx socket through a ring spanner to do the job. Use a jack to raise the hub to take the tension off the link to help get it off and on. It's a very quick and easy affair. After-market links are cheap.
 
seasink said:
Modern drop links have a torx recess in the bolt end to hold it steady. You put a torx socket through a ring spanner to do the job. Use a jack to raise the hub to take the tension off the link to help get it off and on. It's a very quick and easy affair. After-market links are cheap.
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This is also true - I still find the torx versions have the cone spanner cutout too, but either way works.
 
Make sure u jack up both sides so its not under tension.
 
lowpugV2 said:
Thanks for all this. It's going up on a hoist very soon. The lateral movement in the outer driveshafts may very well be normal to compensate for various steering angle plus suspension movement. I have a spare set of known good CVs to compare mine to now.

Whatever the issue is it is getting worse. Had to drive the car and it's mostly fine, but the steering does feel somewhat looser than before all this started. And the clunks are now almost every turn of the wheel.
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No.

Read my explanation above again.

Nothing to do with the outer joint should move under any circumstance.

Things move inside the inner joint, but you can't replicate that by hand unless something is wrong or you have the driveshaft out of the car.

The fact that it is getting worse might suggest something to do with the driveline is amiss. I would stop driving the car until it is diagnosed.
 
Reviving this. New drop links in. Still groan and clunk with steering lock over or up a drive way curb or U-turn. Have replaced a slightly worn steering rod end and a steering ram boot. Drive shafts and CVs all good. Top engine mount is perfect. Every joint has been checked twice.

So, could this simply be strut tops/bearings? They don't make noise if I wind lock on left or right while stationary.
 
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