CV Joint Question???
 

Hi Pelicans...

Wondering if anyone can shed some light on this for me? (RHD '78 911SC)

I have a 'wurring' noise coming from the rear that changes volume (quiet to loud and inconsistant). After reading a few threads, it seems my CV joints may have 'given up' ?

I've checked the condition of the boots etc and all seems ok except the right hand inner boot seems to be different to the other 3? (see pics, and this is a right hand drive car if that makes any difference?). I doubt this could be the cause of the noise, but should I change it? Also, am I on the wrong track with thinking the CV's are the problem noise?

I checked through the service history of the car and apparently the wheel bearings were changed and the CV joints re-packed in Jan '10.

Any assistance is very much appreciated!

LEFT
http://i26.photobucket.com/albums/c1...ftHandSide.jpg

RIGHT - DIFFERENT TO OTHER THREE and seems to cover the joint???
http://i26.photobucket.com/albums/c1...htHandSide.jpg

The left flange/boot is the old style, the kind that wraps over is the newer style with replaceable boot.

FYI, when you change to the newer style, you may or may not need slightly shorter bolts to make up the difference.

Noise could be any number of things, but at least that answers the boot question. :)

'wurring' noise could also be rear wheel bearings. Pretty common wear part, and if your CV joints look fine, then that could be it.

...especially if the noise changes when making left or right turns...

FIG,

First, re-torque the CV joint bolts.
Be sure to use a calibrated torque wrench.

Grab each axle shaft in the middle and move it axially.
Is there a difference left-to-right?

With the rear wheels off the ground (neutral, parking brake off) grab the tires and wiggle (up-down, left-right) to see if there is movement.

Inspect the engine-to-transmission nuts for tight.
Inspect the transmission and engine mount hardware for tight.

Here is ‘almost everything you need to know about CV joint bolts’.
http://forums.pelicanparts.com/porsche-911-technical-forum/222537-reconstructing-constant-velocity-cv-joints.html
It is very long but VERY worthwhile reading.

Note: you have too long CV joint bolts here (red arrows).
Spec is 1-2 threads protruding with 1½ thread ideal.
Always use new Schnorr washers.
Re-torque after ~100 miles.

http://forums.pelicanparts.com/uploa...1299594945.jpg



I agree about a ‘turning test’.
A freeway cloverleaf interchange is a good test track for one direction.

Best,
Grady

fastenal sells the bolts in 5mm lengths and the washers too. you have to buy a bag of 50, but they are not that much.

i would rather have too long than too short.

Thats what she said.

Does the noise occur when you put a load on the car, and does it goes away when you let off; is it gear dependent? Were the rear wheel bearings changed (kind of a hassle) or just the front and are you sure the noise is coming from the rear?

MysticLlama, thanks for the info!

cbush, the bearings were replaced last year so I hope not, but will check.

IROC & tobluforu, the noise is inconsistant (happens with steering straight, turning, on and off load... gets louder and softer, in and out?)

T77911S, cheers for that!

Grady Clay, I re-torqued (to 33lbs), no difference left to right axially, no movement with the wheel test. I havn't checked the tranny to engine yet... will do! Will get some washers. Thanks so much for your effort in replying!

I will try the 'freeway turning' test and see if the noise is more evident?

My intention is to do an engine drop (I have a hoist in my warehouse) when I'm back from vacation and repair some oil leaks from top/rear of the motor. Of course, I need to remove the axels from the transmission to do so, so I was going to replace the CV's (as they haven't been according to vehicle history?) Hopefully it's the CV's and replacing them will rid me of that noise? If not, at least my CV's will be new... LOL.

Thanks everyone for their advice, as usual, can always count on the Pelicans!!!!

Here is a pic of the RHS inner CV, are those wear marks the cause of my noise do you think?

I've since re-packed and installed the same CV and replaced the bolts (shorter bolts and added shnoor washers).

Noise is still there.

Unfortunately Pelican dont have CV's in stock ATM (thats why I re-installed), but are trying to source for me.

I'll replace all four.

http://i26.photobucket.com/albums/c1...Jointswear.jpg

CV's replaced = Noise stopped!!!!
FTMFW!

Some good info. Mine look much the same as yours. It's on my to do list.

CV's were relatively easy... the wheel bearing on the other hand... NOT SO EASY (but completed!) :)

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