Dee_82

Mondeo Mk4 2.0TDCI Front end knocking / rattle

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 Another day another problem

Getting a lot of knocking and rattle on the front end, probably drivers side.

100% reproducible.

if the car is underload or braking, no rattle/knock. if its not underload or braking either with the clutch engaged or disengaged, it knocks around a lot, not always in response to bumps on the road.

initial thoughts were the drop links, but I replaced one and its absolutely fine, the old one was perfect, no change, next up was the control arm but its appears fine, both sides of the main bush look good, the front one is impossible to see anything on. if it were the control arm why would it stop under load or braking? pushing side to side and up and down produces no knock.

That leaves me with the strut or the drive shaft, any thoughts?

 

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Does it definitely sound like metal knocking or a dull thud like sound, like plastic 

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good question, it sounds like a dull thud but the kind you get from a large lump of solid metal! lol

but maybe it is plastic, but if so I guess the next question would have to be, why would accelerating or braking stop it or reduce it enough to make it unnoticeable? 

 

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I had a similar noise and feeling previously on a Vauxhall Astra. 1st i found that the upper most coil on the suspension spring had done a runner, swapped it and got same noise lol. Eventually (staring straight at me) i noticed the plastic cover (the one that fits over the strutt but inside the spring) looked like someone had used something like a long screwdriver and had peeled a wedge of said plastic to one side, so when the suspension travelled downwards the spring would catch the plastic that was sticking out and made a noise of dull plastic thud and a TWANG from the spring. Might also be worth cheching the top mount.

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interesting, thanks guys, im going to get the car up on stands tomorrow then offload the weight of the wheel on to some bricks, a chap was telling me today that sometimes the weight of the arm pulling down can cause it to sound fine, but once offloaded it can play up. whilst under there ill see if I can get a look up the top of the strut.  what why would it stop knocking under load / braking, its that bit that I dont understand...

just to add to this though, I was coming home today and hit a newly surfaced pic of road that has been recently chipped and oh my god, ive never heard such a racket. it was almost like a constant grinding / knocking sound, loud enough to hear and feel though the floor pan and all the peddles. which would go if I sped up enough and get the good amoint of load put to the wheels. the road was flat but the uneven surface of the stones sent whatever was wrong in to a fit. I almost decided to stop the car thinking id sheered off a drive shaft. 

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Had her up in the air today, ill be damned if I can find anything wrong though, yet the video below tells me something is amiss1:05, is the first tell tail knock, up the hill, despite it being quite bumpy, nothing, at 1:55 the mega rattle starts. then going back down the same hill whilst coasting shows what it sounds like when not under load.

I cant rule out anything except the droplink 😞 

 

 

 

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Have you jacked the car up and checked the wheel to see if theres any play/give when manually rattling it?

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I had something similar turned out to be the exhaust knocking on the floorpan at the front.

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I have wobbled the wheel from 9-3 and 12-6 and theres no noise. 

Ive wacked the tyre with a large hammer and felt no knocking on the swaybar, drop links,  tie rod ends, strut, control arms or the knuckle itself. . I even used my wee stethoscope probe and heard nothing at all. 

rotating the wheel showed no sign of a wheel baring going, fully turning the wheel to full lock showed no signs of the strut moving poorly. 

No Obvious leakage on the strut, and bouncing up and down and rocking side to side showed no sign of anything, wrong. I tried pushing all four corners and no obvious sign of the strut not working.

I grabbed the exhaust after the DPF and was able to wobble it about, side to side up and down and forward and backwards, the DPF pressure hoses were knocking on the heat shield which I moved a bit to the side but it made no difference, the shield is fully attached.

The only thing I haven't checked is the engine mount and torque limiter or manipulate the control arm, I suppose I didn't check the CAT before the flex joint either.

 

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That sounds like a ball joint to me, try a pry bar between the hub and wishbone and see if you can get any play in the bottom BJ.

Next would be the shock - while it might bounce fine and not leak, if it can't rebound quickly enough over rough surfaces that's the sort of noise you get.  

Finally would check the CV joints/diff.  They are 'slack' while not accelerating or braking.  I've got a dodgy CV joint on the A3 that I've felt for weeks, and does knock a bit, but it's just this week started clicking on corners so I can finally prove it's that CV lol.

It is also worth checking plastic parts, it's surprising how much noise a loose headlight can make after bulb changes.

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I just had to replace my shock on mine was causing that issue. the garage could only find the noise if the car was on the floor and you grabbed the wheel in the 12 position and pulled and pushed the tyre (in to engine and out to kerb)

so ive just replaced both the front and they were both well and truly knackered.

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cheers guys, ill see what I can do, I was wondering if the inner CV joint would cause this? I dont think there is any loose plastic and im not sure anything plastic could cause vibrations in the floor and peddles.

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alrighty, made some progress, finally been able to make it knock by hand, still none the wiser whats knocking as its vibrating through everything, strut, coils, drop links, control arms and tie rod ends.

So it only does it by hand in a very specific position


its the front right wheel and the wheel needs to be on full left lock, the wheel needs to be loaded up, ie, on the deck., it might not be relevant and ill test later but the road was slight cambered so the front left was a little lower than the front right..

Grab the front right wheel (which is turned left) at 11 oclock and pull at 90 degrees to the car with a very short sharp yank.
Single clonk.

Double checked the steering lock was disengaged, tried it with and without the engine running, clonk.
Big pulls, rocking, nothing, sharp tug, clonk

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sounds like the shock as mine did similar. 

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Just read this topic and can hear why your taking suspension apart now. 

That's a nasty noise. Have you checked the engine mountings ( top one and rear one? )

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12 minutes ago, iantt said:

Just read this topic and can hear why your taking suspension apart now. 

That's a nasty noise. Have you checked the engine mountings ( top one and rear one? )

Not sure what I can check with that top one? its completely contained in metal.  On my focus I was able to see the rubber fall to bits. I could jack it up with some wood on the sump but what would be considered normal movement, I suppose if I jack it up half an inch or so and release the jack it might drop and knock?

I dont think its the torque restrictor mount, it looked ok and the noise is 100% coming from the front OSF of the car

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55 minutes ago, iantt said:

Have you got a decent spring compressor if your going to do the strut top? 

Yeah, that part im fine with, getting the damn control arm out off is my concern, if the strut is nackard then replacing both is one thing, but replacing both and the control arms is a different matter, if I had the cash id just do the whole damn lot but im also having to replace the turbo, not having much luck here! 😞 

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@iantt

I got someone to take a wee video whilst I rocked the car with the clutch and the hand brake on, couldn't hear any knocking but it moves somewhat, that mount also gets really really hot, I reckon it would cook an egg its so hot. The knock is definitely on the drivers side of the car though. I had no idea the engine cover does that funny wobble, its mounted on all it rubber mounts and doesn't touch anything.

Your expertise would be most welcome!

 

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i tried viewing video but for some reason my tablet wont play it. will try with my phone later. 

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