Worn CV joint?

[Dippydog]

There is a noise and vibration felt through the car which from reading up appears to indicate a shot inner CV joint[or possibly a shot support bearing on the offside shaft?] is there a way without dismantling to tell which side joint it might be? The noise/vibration is definitely rotational as the car doesn't do it if stood still and the engine revved and seems to come in at speeds from about 15mph-but could be present below that but less noticeable.Only other clue I can offer at present[yet to get under the car for a proper look]is that the symptoms get slightly less noticeable on left hand bends. The car is a "Y" reg[year 2000] C70 convertible with the 2.4 lpt petrol engine and manual gearbox.
TIA.

[Luxobarge]

To check for a worn wheel bearing, jack the car up and spin the wheel. Put your hand on the suspension spring, and if the bearing is worn you'll feel a vibration, a sort of grumbling feeling. Alternatively get a long screwdriver or other solid bar, rest one end on the suspension strut and put the handle of the screwdriver against your ear, and you'll probably hear the grumbling noise, and possibly feel it in the screwdriver too.

If it's less pronounced on left hand bends, (therefore more pronounced on right hand bends, presumably) it's probably the left wheel, as this is under less load on left turns and vice-versa.

If it's the CV joint, these more usually make a cracking groaning noise on full lock - I'm not sure how you tell which side, but if it were me I'd lean towards doing both sides, as if one is shot the other probably isn't far behind.

Hope that helps?

[Dippydog]

It's been making this noise[although getting worse I think]since she bought it a short while ago and at first we thought it to be the n/s wheel bearing,so we replaced that-it was on its way out anyway-but that didn't cure it.We've also replaced the front mount/bush on the upper steady bar which was shot and the front engine mount-the one on the drivers side near the crank pulley-as the rubber on this had parted company with the base plate.The car has been driven slowly in circles on full lock to listen for any clicking noises from the outer CV joints but no noise was evident when doing this so at present we've ruled out the outer joints which leaves we think the inner CV joint[s] and/or the support bearing on the o/s driveshaft.It will now be next week weather permitting before I can get back under the car to try and check.The parts replaced so far have needed replacing so we've not wasted money chucking new parts on when they weren't necessary,but throwing one or both driveshafts at it if they're not needed would start to become expensive guesswork,so if these can be checked in situ that would be helpful.

[Clogs]

I had this noise. I had the wheels up to check the bearings. Yes there's some slack in the CV joints but no rotational noise.

After much investigation of the front of the car, the culprit was a disintegrating rusty back plate of the nearside rear brakes. Backplates replacement has cured the problem. You have to have the bearings off to fit new ones.

So give it a try: rotate the rear wheels and see if anything is rubbing as the backplate will be rusty and possibly falling apart and catching on something - tyre or disc.

[Dippydog]

Thanks for the pointer.If nothing is found "up front" when I get underneath it I'll give those a look.

[Dippydog]

Managed a quick look underneath the C70 today[with my V70 in attendance for possible comparison]couldn't detect any play in drive shaft joint[s] or the support bearing.However comparing the two-my V70 is a 2.4 petrol manual where her C70 is a 2.4 turbo petrol manual-the rear mount from the gearbox on mine is a sort of cone shaped thing where hers has a dome shaped rubber bump stop looking affair at the lower mounting point and a square rubber block on the mounting point on the gearbox bracket with a significant gap between the two!! So basically where the rear gearbox/engine mount should be there's nothing actually supporting the engine/gearbox at that point.

[ITSv40]

Originally Posted by Dippydog

Managed a quick look underneath the C70 today[with my V70 in attendance for possible comparison]couldn't detect any play in drive shaft joint[s] or the support bearing.However comparing the two-my V70 is a 2.4 petrol manual where her C70 is a 2.4 turbo petrol manual-the rear mount from the gearbox on mine is a sort of cone shaped thing where hers has a dome shaped rubber bump stop looking affair at the lower mounting point and a square rubber block on the mounting point on the gearbox bracket with a significant gap between the two!! So basically where the rear gearbox/engine mount should be there's nothing actually supporting the engine/gearbox at that point.

Completely different set up on the later C70. Your step-daughter's C70 has the later XC70 gearbox mount located on top of the subframe on the near side. If you remove the front wheel and look into the wheel arch behind the suspension strut you will see a very substantial mount.

A drawback to this setup is that the mount needs to be removed to drain and refill the gearbox, whereas on your V70 the gearbox filler is easily accessible.

[Dippydog]

More time to look at this today and unfortunately it seems the gearbox/diff is the culprit.As the car selects all gears smoothly I'd say it's the diff.With both front wheels in the air there is quite large amount of free movement on the n/s wheel before any "take up" and certainly more than at the o/s wheel.So the hunt it would seem is on for a reasonably priced replacement 'box.The label on the gearbox identifies it as a M56HK although whether one of the other 'boxes would be a straight swap I don't know.Cv joints have been checked and there's no play in those.

[s1monc]

If it was the diff why would the noise get quieter on left hand turns?

I have a groaning/whirring noise on one of my T-5R’s that I thought might be gearbox related. It’s got a lot louder after a 400 mile M way journey on Monday to the point that I can actually hear it a lot more when turning left which makes me think it’s the o/s/f wheel bearing. I’ve ordered one anyway.

[Dippydog]

Sadly it's not the wheel bearing as we replaced that and with both front wheels in the air with someone in the car to put it in gear and let the clutch up while another was underneath to try to pinpoint where the noise was coming from it's definitely the gearbox/diff.Quite why it would get slightly quieter on left hand bends I haven't a clue.Anyway if the numbers cast into the gearbox casing mean anything we've found a gearbox not too far away[the seller is unsure whether it's a M56L or M56H as the label is missing the only thing they point out is that it has the "fatter" input shaft with 21 splines which is not a distinction I've seen mentioned anywhere else]Two more questions then arise firstly how many new bolts will be needed for the subframe? and secondly Haynes says the nuts for the steering gear must also be renewed,why?