Suspension knocking

[AdrianL]

So, unfortunately I've had this issue since I bought the car, but I'm getting closer to figuring it out! I took it to the garage and he couldn't see anything wrong with it (just as the previous owner said). Nothing looks loose or out of place. However when at slow speeds, going over bumps etc, there is a knocking noise. Now I knew the rear AP coilover shockers were leaking, so I assumed the noise was those, and have tempolarily changed back to stock shockers on the rear, but the sound is still there.. however I noticed if I bounce on the N/S/F corner, it makes a noise. I took a couple of videos:

First one just shows the suspension components... all looks OK to me? I couldn't shake anything loose:
http://youtu.be/N5WV3j2soiA

The second one demonstrates the noise.. turn your volume up:
http://youtu.be/WQhOnHHyNUY

Bonnet View of tops (I believe the gaps are normal?):
O/S/F


N/S/F


Any ideas? from what I've read, it may be a top mount bearing?

Thanks,
Adrian

 

[YellowLCR]

check anti-roll bar bushes/drop-links or ball joints, I've replaced both on mine.

 

[AdrianL]

check anti-roll bar bushes/drop-links or ball joints, I've replaced both on mine.

I'd given the drop links a good tug with no movement, but I don't think I checked the anti-roll bar. How can I check the ball joint?

Do you think it's unlikely to be the top mount?

Thanks,
Adrian

 

[wildrides]

I would suggest you check

Top mount bearings
Pinch bolts tight on strut bottom
drop links
balljoints
wishbone bushs intact
subframe to body shell mounts for slack mounting bolt
Front wishbone bolt torqued up
ARB rubber bushs present
Passenger side gearbox/engine mount intact

 

[Kambo]

Long shot but check your brake calipers aswell, had a similar thing on a previous car with a knock on speed humps only and spent a shed load on replacing all front suspension components only to find one of the calipers only had one bolt holding it in! Previous owner denied everything blah blah blah

Get a long bar and prod lever poke everything down there

 

[dgjdrummer]

I have the same thing, have managed to get under the car and push/pull everything abd the sound is definitely coming from the top mount area.

Wildrides, how would I check the top mount bearings without talkingng everything apart? I don't have the tools to remove the struts or a torque wrench to put it all back together :S

 

[AdrianL]

I would suggest you check

Top mount bearings
Pinch bolts tight on strut bottom
drop links
balljoints
wishbone bushs intact
subframe to body shell mounts for slack mounting bolt
Front wishbone bolt torqued up
ARB rubber bushs present
Passenger side gearbox/engine mount intact

So yesterday I jacked the car up and got it on axel stands. When pushing down on the suspension I couldn't really hear anything when the front end of the car was hanging down?

I looked at the majority of what you mentioned, and nothing was loose - and all bushes look intact. There's only one thing I could see that was on the (I believe is called) the tie rod end? there's a little gap between the bush and the metal, but this could be to do with the car being jacked up? Please see the 3rd image at the end of the post.

I took a couple more snaps to see if anyone can spot anything obvious.

Long shot but check your brake calipers aswell, had a similar thing on a previous car with a knock on speed humps only and spent a shed load on replacing all front suspension components only to find one of the calipers only had one bolt holding it in! Previous owner denied everything blah blah blah

Get a long bar and prod lever poke everything down there

Thanks, but deffo not the caliper.

I have the same thing, have managed to get under the car and push/pull everything abd the sound is definitely coming from the top mount area.

Wildrides, how would I check the top mount bearings without talkingng everything apart? I don't have the tools to remove the struts or a torque wrench to put it all back together :S

It's so hard to tell, but I think it's coming from the bottom for me. I can only hear the noise when the vehicle is on the ground though.

 

[wildrides]

Looking at the images , particularly the first image I believe that may be your problem :-

The wishbone shown in the image has been fitted with non standard purple polybush . Often people fitting these bushes fail to understand that the inner metal sleeve of the bush, that the bolt passes through, is supposed to be clamped absolutely rigid and tight in the subframe so that it cannot pivot or move in the subframe . The only movement that should occur is the actual polybush flexing . This is achieved by tightening the bolt passing through the bush until the subframe bends enough to clamp on the metal sleeve . On the standard bushes the central inner metal sleeve is actually serrated on each end to promote grip on the subframe and prevent the metal sleeve turning in the subframe .
My belief is that one of these bolts on your wishbones front and rear bushes has not been tightened enough and as a consequence the inner metal bush is rattling in the subframe socket.

As an aside these bolts should only really be fully tightened with the weight of the car on all four wheels .This is so that the rubber bush is in relaxed state when the car is at its natural ride height . This is of course impossible without a four post liftiing ramp so that you can access the bolts with the car off the ground but with the wheels taking the weight evenly on all four wheels . You can get around this by measuring the gap to the wheel arch with the car naturally settled and then recreating the same measured gap on just the wheel you are working on with a jack under the body and another under the wheel .

 

[AdrianL]

That's very interesting. Thanks for that . It's odd that it's only doing it on one side though, perhaps one side was tightened more than the other?

So is the fix to this quite simply tightening it up when the entire car is on a 4 wheel lift?

Thanks again,
Adrian

 

[AdrianL]

Also, what's your opinion on the 3rd picture? As I see some bare metal there... unless that is normal?

Thanks,
Adrian

 

[wildrides]

I am basing my assesment on the fact I can see some shiney metal at the top of the bush in picture one which looks like it has been polished by a repeated hammering contact on the subframe socket upper surface.

However picture 3 could indicate a loose track rod end taper . Again try tightening up the nut to the correct torque . You will probably will be able to pull/ push the track rod end taper in and out of its seat by hand if it is loose . I think that in this case it may just be that someone has pushed down the rubber dust cover to have a look and its stayed there ( your garage check over )

 

[AdrianL]

I am basing my assesment on the fact I can see some shiney metal at the top of the bush in picture one which looks like it has been polished by a repeated hammering contact on the subframe socket upper surface.

However picture 3 could indicate a loose track rod end taper . Again try tightening up the nut to the correct torque . You will probably will be able to pull/ push the track rod end taper in and out of its seat by hand if it is loose . I think that in this case it may just be that someone has pushed down the rubber dust cover to have a look and its stayed there ( your garage check over )

OK brill, I'll look into getting that sorted then. Presumably I'll need a new bolt for the wishbone if the subframe has been rubbing against it? or recon it will be alright with just been tightened up? I think I'll use the jacking technique you described before to try and get it sorted.

Thanks,
Adrian

 

[Paul80]

I had a bad knocking coming from the front passenger side of my Lcr, had my track rod ends changed on Friday and now there's no knocking at all. Happy days