C70: Knocking and steering vibration at speed - CV or bearing?

[StatusRed]

Hi all,

I've been living with a knocking sound on uneven road in my C70 but the other day on the motorway I started noticing quite a bit of vibration through the steering wheel at 70, slowed down to 60 and this went away but the steering still feels a bit loose and slidey. I suspected this to be a wheel bearing as it was mentioned when I got my wheels aligned a few months ago too.

I jacked the car up this morning and couldn't feel any excessive wobble in any of the wheels but they don't move as freely on the drivers side as they do the passenger side.. The lack of the wobble has now made me think maybe its a CV joint and not a wheel bearing.. Any ideas?

[tdidave]

Originally Posted by StatusRed

Hi all,

I've been living with a knocking sound on uneven road in my C70 but the other day on the motorway I started noticing quite a bit of vibration through the steering wheel at 70, slowed down to 60 and this went away but the steering still feels a bit loose and slidey. I suspected this to be a wheel bearing as it was mentioned when I got my wheels aligned a few months ago too.

I jacked the car up this morning and couldn't feel any excessive wobble in any of the wheels but they don't move as freely on the drivers side as they do the passenger side.. The lack of the wobble has now made me think maybe its a CV joint and not a wheel bearing.. Any ideas?

Unfortunately the lack of wobble on a bearing doesn't always mean its not shot. It confuses matters I know, but I've been caught out by this very thing. The bearing was seizing up and giving the impression there was no play. A giveaway for this is normally heat.

The wobble/vibration could also be wheel balance of course.

Knocking on uneven road can also be something simple like a drop-link. I can't see a link causing vibration at speed though.. but it just may well be a coincidence, and you have two things going on at once.

Re the CV joint, a normal test for this is to put the car on a tight lock on both turns, and normally you get a clicking sound if a CV is gone, or well on the way. Also, if you grab the drive shaft with the road-wheel locked you can normally feel the play in a CV joint, there should be none.

Dave..

[amazondean]

the wheels may not spin evenly as it depends how much drag the brake pads are having on the discs. Usually a wheel bearing would start to hum, but not always. It could also be your top rubber spring mount that has parted company. You can check this by undoing the top nut, taking out the spacer/washer and having a look at the rubber. You can do this without worry of any danger. Or as suggested, a drop link. I had one loose once and it was banging for long enough before I noticed and tightened it up.

If the CV joint is on its way out, they usually play up worst when the steering is at full lock!

Also, just check that your wheel nuts are tight!

[StatusRed]

Originally Posted by tdidave

Unfortunately the lack of wobble on a bearing doesn't always mean its not shot. It confuses matters I know, but I've been caught out by this very thing. The bearing was seizing up and giving the impression there was no play. A giveaway for this is normally heat.

The wobble/vibration could also be wheel balance of course.

Knocking on uneven road can also be something simple like a drop-link. I can't see a link causing vibration at speed though.. but it just may well be a coincidence, and you have two things going on at once.

Re the CV joint, a normal test for this is to put the car on a tight lock on both turns, and normally you get a clicking sound if a CV is gone, or well on the way. Also, if you grab the drive shaft with the road-wheel locked you can normally feel the play in a CV joint, there should be none.

Dave..

I'll try to give the CV joint a shake to see if it has play in it.

Originally Posted by amazondean

the wheels may not spin evenly as it depends how much drag the brake pads are having on the discs. Usually a wheel bearing would start to hum, but not always. It could also be your top rubber spring mount that has parted company. You can check this by undoing the top nut, taking out the spacer/washer and having a look at the rubber. You can do this without worry of any danger. Or as suggested, a drop link. I had one loose once and it was banging for long enough before I noticed and tightened it up.

If the CV joint is on its way out, they usually play up worst when the steering is at full lock!

Also, just check that your wheel nuts are tight!

I'll give the rubber mount a look then, and yes all wheel nuts are tightened to 110nm, checked this morning. Thanks!

Oh, I should have probably mentioned that the ABS light has been on since I had the car by the way.. I read this can be to do with the wheel bearing?

[tdidave]

Originally Posted by StatusRed

Oh, I should have probably mentioned that the ABS light has been on since I had the car by the way.. I read this can be to do with the wheel bearing?

I have heard that, but never come across it personally..

Good luck with your investigations..

Dave..

[Baffler]

Originally Posted by StatusRed

I've been living with a knocking sound on uneven road in my C70 but the other day on the motorway I started noticing quite a bit of vibration through the steering wheel at 70, slowed down to 60 and this went away but the steering still feels a bit loose and slidey.

Check the steering rack for movement where it's attached to the subframe. The brackets that hold the steering rack in place can separate a few mm allowing the rack to move about and tap against said bracket.

You may also have some gear lash on the rack and pinion which is causing it to feel loose. An adjustment is possible on the rear of the rack (SIMI type rack only I think). Do a search for same.

[StatusRed]

Originally Posted by amazondean

It could also be your top rubber spring mount that has parted company. You can check this by undoing the top nut, taking out the spacer/washer and having a look at the rubber. You can do this without worry of any danger.

I tried to undo the washer today but the whole thing tries to move round, not just the nut.. Is the car meant to be jacked up when undoing this?

Originally Posted by tdidave

Re the CV joint also, if you grab the drive shaft with the road-wheel locked you can normally feel the play in a CV joint, there should be none.

Again does the car need to be jacked up to check this?

[tdidave]

Originally Posted by StatusRed

I tried to undo the washer today but the whole thing tries to move round, not just the nut.. Is the car meant to be jacked up when undoing this?



Again does the car need to be jacked up to check this?

In both cases.. NO.. it doesn't. It just makes it easier on you if you've got to lay on the ground to carry out your inspections. Re the nut on the top of the strut. There's a flat there to stop the rod from spinning when you loosen the nut.

Dave..

[StatusRed]

Originally Posted by tdidave

In both cases.. NO.. it doesn't. It just makes it easier on you if you've got to lay on the ground to carry out your inspections. Re the nut on the top of the strut. There's a flat there to stop the rod from spinning when you loosen the nut.

Dave..

I don't know what you mean, it seems like the entire rod is turning when I try to undo the bolt hence why it won't undo. Maybe it's seized?

[ITSv40]

the attachment shows the top mount on my C70. the rusty looking rod above the nut is the damper rod which has the flats on to hold while undoing the nut.