Can bad 4WD fr. wheel bearing cause CV joint to go bad

[84FLH]

Ongoing research....

2000 Mountie. 4.0 SOHC. 320,000. Runs good for it's mileage.

With hands at 12 and 6 o'clock on driver's front tire, wheel bearing has 1/8"-1/4" movement. But I've no howl, whine, grinding or other noise typical for bad wheel bearing.

3 days ago I heard two extremely loud metal on metal bangs, about 1 second apart, from front end while driving 5-10 MPH in straight line.

I stopped and looked under vehicle. Found nothing obviously wrong.

Continued driving slowly, straight. Got the 'double tap' bang once more. Another under vehicle inspection found nothing out of order.

Drove 15 miles home 50 MPH without further banging.

Enroute to work next day, the 'double tap' banging returned. About 4 times w/in 100 yard stretch.

Could the bad wheel bearing be causing the CV joint to make this noise?

It's *very* loud. Like someone hitting frame with 2lb sledge.

My impression was of a spinning metal part hitting another. Or a heavy metal part under tension being let loose and hitting a solid metal part.


Thanks everyone for your answers.

 

[German Engineer]

It's very common for CV joints to make loud knocking noises when they go bad.
Usually (but not necessarily always) the knocking will change when steering in one or another direction it tends to get louder when accelerating, and the rhythm varies with speed.

Usually the effect is most pronounced when accelerating in a very tight left or right turn. If it's a bad CV joint you'd typically want to replace both on that side.
If the knocking comes from a bad CV joint it's not necessarily a repair that absolutely needs to be fixed immediately if you don't have the money. Wheel bearings and CV joints can make a lot of noise and be really annoying, but still run quite a long time damaged like that. Although that is of course not really recommendable, because of added stress on other components like differentials etc, but in the past when I was a student I've driven cars with knocking CV joints for months before I had the money to replace them or sent the car to a junkyard because of other problems that wouldn't let it pass German emissions tests and technical inspections.

 

[84FLH]

It's very common for CV joints to make loud knocking noises when they go bad.
Usually (but not necessarily always) the knocking will change when steering in one or another direction it tends to get louder when accelerating, and the rhythm varies with speed.

Usually the effect is most pronounced when accelerating in a very tight left or right turn. If it's a bad CV joint you'd typically want to replace both on that side.

Will the loud knocking be in quick succession, about 1 second apart, and then reoccur once within about 25 feet to 50 feet from the original occurrance?

 

[German Engineer]

It depends on how fast you drive and how fast the CV joint rotates but 1 sec can be possible.
The cars I had went "bop, bop, bop, bop, bop,..." with maybe 2 or three knocks per second, but as I said it really depends on the speed and the condition when it occurs. And 5 Mph is really slow.

As I said, try if steering and accelerating out of a tight (left and right) turn makes it louder. Depending on the side it's usually louder in one turn than the other and less noisy when driving straight and cruising than when accelerating and the CV joint is under load.

You can also jack the car up and rotate the wheel by hand and you should be able to feel it then.
It's really easy to diagnose, easier than describing how in a forum. It's usually very obvious if the knocking comes from a bad CV joint, unless the joint is really just starting to go bad. As I said steering and accelerating out of a very tight turn is a good way to put the CV joint under maximum load and typically that will force a bad CV joint to knock louder and more noticeable.

in your case since you have play in the wheel bearing that will probably also affect the conditions of when the CV joint knocks and when not, but accelerating out of a tight turn left and right and comparing should also move the wheel from one end of the zone of play to the other as well. So you should probably notice a change in nocking when you try that and compare.

 

[84FLH]

Thank you German Engineer.

After having the banging noise return Friday morning, I decided to drop it off at the mechanic's on the ride home from work.

I really wanted to drive it home and diagnose it over the weekend, but when I left work Friday afternoon I worried that whatever was causing the banging sounds might lock up the tire and cause me greater problems.

I also don't have a second vehicle, or a garage to trouble shoot in. I learned long ago that if you're going to try to be your own mechanic and do more than brakes and shocks at home, then you really need another vehicle so that you're rushing to fix your car in time for work Monday.

Will post back here when I find out what's wrong.

Thanks again.

 

[German Engineer]

Thank you German Engineer.

After having the banging noise return Friday morning, I decided to drop it off at the mechanic's on the ride home from work.

I really wanted to drive it home and diagnose it over the weekend, but when I left work Friday afternoon I worried that whatever was causing the banging sounds might lock up the tire and cause me greater problems.

I also don't have a second vehicle, or a garage to trouble shoot in. I learned long ago that if you're going to try to be your own mechanic and do more than brakes and shocks at home, then you really need another vehicle so that you're rushing to fix your car in time for work Monday.

Will post back here when I find out what's wrong.

Thanks again.

The play in the bearing is the bigger problem, but if you're lucky and the bearing makes no noise that might be easy to fix.
The knocking - if it comes from the CV joints and not from the play in the bearing is something that sounds scarier than it is.
Of course it's always better to fix these things quickly, especially with AWD, but knocking CV joints and bad bearings tend to make a hell of a noise. And usually it takes quite a long time for them to go so bad that they can then completely break and lock up a wheel.

From what you describe I wouldn't be surprised if they just replace the bearing and the two CV joints on that side. It's a relatively quick fix and the parts shouldn't be all that expensive. Not having the proper tools is a real problem, so I've always had that done in a shop also.

Have them show you the parts that they took out if they can.
I would expect the wheel bearing to be bad, but it might theoretically also be possible that it just needed to be adjusted/ tightened.

Oh and if they want to charge you for wheel alignment, then take a really good look at the report and let them show you and explain the values before and after the alignment, because I wouldn't expect an alignment to be necessary unless there's some other reason than the play in the bearing and the (eventually or likely) bad CV joints.