Dodgy CV Joints - dangerous??

[vickyclare]

Hi there,

I've recently had my car inspected and been told that both of the rear CV joints on my car are totally gone.  Everytime i turn a corner theres an awful loud clicking/creaking noise from the back.  I've booked it back in with the dealer to get repaired but they can't do it for another two weeks.  Meanwhile I have some very very long journeys to do.  Is it safe?  What's the worst that could happen? 

[KebabMeister]

Well I assume that it is a rear wheel drive car with drive shafts rather than a solid axle?  What car is it?

The worst is that they could seize up and lock the wheel up causing you to spin and crash, or totally disintergrate causing the hub to break and your wheel flying off.  Both are these are extreme cases but still possible.  Get them seen to asap.  (front CV joints far more serious/danagerous than rear, but are still serious nonetheless).

[vickyclare]

Oh my god, I didn't think it was that bad!  You've put me off driving it now.

It's a Vauxhall Corsa and yes its the driveshaft cv joints (I know nothing about cars, just reading it off the report!)

What are the chances of any of that happening?  Or rather, if it was your car, would you still drive it 100 miles and back?

Thanks for the reply!

[KebabMeister]

Well, a Corsa only has CV joints on the front.  The rear just has independent suspension with wheel bearings.

So, if they've mentioned CV joints it must be the front.

CV stands for Constant Velocity.  There are drive shafts that come out of the gearbox and transfers drive to the road wheels.  To allow for steering and bumps etc., a CV joint is required.  There are rubber boots that protect the actual joint but if these are damaged then the grease will spray out of the joint and if the hole is bad will let water in (condensation can build up in there too causing rusting).  The most probable worst case would be that this joint would seize up causing your wheel to lock up and skid.  The joint could also disintergrate if it happened at high speed and allow the drive shaft to break free and the amount of damage that could cause be catastrophic not only in safety terms but damage to your car.

I haven't a clue what the chances of that happening.  It could be 100:1.... but you could be the '1' !  This item would fail a MOT instantly.

No, I wouldn't drive it 100 miles and back knowing that the CV joints are faulty.  Depending on the severity I would probably only use the car under speeds under 30mph and for short journeys only.

[vickyclare]

Oh sorry, I'm reading it wrong.

The report says:

Needs o/s + n/s front outer cv joints on driveshafts, noisy when turning left and right

Apparently the car was driven for a while without the caps and they've been weathered but the dealer did the MOT and just greased the joints and replaced the caps, not the cv joints. 

Does that make it any better? lol

[KebabMeister]

It does make sense.  It might be worth having them removed and inspected.  You say that they were weathered, well, it's hard to say whether there was any corrosion or other wear.  The fact that he passed it would indicate that they are now safe. 

Could you clarify that they are still noisy and still need replacing?  You last post didn't make it clear.

[KebabMeister]

mdoo, some cares with rear wheel drive that don't have a solid drive axle have drive shafts with universal joint (UJ) like CV joints instead.  I think some Jaguars have them like that, not sure on other cars.

[vickyclare]

Yes still very noisy and two days ago mechanic has told me they need replacing.  the MOT was done 2 weeks ago, the day i got the car.
thanks for all the replies!

[ianess]

Just goes to show what a useless piece of paper an MoT certificate is!

Take care.

[Tim Baxter]

UJ's are used when the flex angle is small say in fwd between the gear box and hub or in rwd in the prop shaft (and half shafts if it's not a rigid axle)

Where the flex angle is large (as in steering wheels) then the torque on a UJ would be more than its simple mechanics could cope with.  The CV joint has a splined shaft going into the inner of the joint.  A ball bearing race keeps a ball bearing into each groove in this inner part and they then, in turn, engage in grooves in the outer.  When these parts wear the noise is produced by the ball bearings 'clicking' in and out of the worn grooves.

[v64paul]

cv joints are used to allow the wheels to move in relation to the driveshaft. this can be on a rear wheel drive car with independant suspension, eg sierras and granadas although thats going back a bit...

[Tim Baxter]

Seeing as we've hijacked this topic (sorry) I don't understand which machines you're referring to, mdoo.  I also understand that BMW use CV in the rear drive train.

[Tim Baxter]

Gotcha Mdoo, I see their road cars all over the place, especially near Cheadle and Uttoxeter, easily distinguished by the registration!