While putting on my snowtires earlier today, I noticed that the right front driveshaft/axle on my A4 Avant 1.8T is very rusty in the area where it steps down from the big diameter shaft running to the engine and the smaller diameter shaft to the wheel. I don't mean just a little cosmetic rust, I mean the black coating on the axle, and the rust under it, is flaking off in pieces typically of about an inch square in area, exposing the entire circumference of the shaft for a distance of about five inches. The pieces of combined paint and rust are a good 1/16" thick. Most of them I could just flake off with a fingernail, but I also banged off what was left with a chipping hammer.

Is this a problem? Are these driveshafts hollow? should I change this piece out before it snaps, or is it going to take a lot more than a few sixteenths of an inch of rust to affect one of these pieces?

 

quite common actually and no big deal as they are solid, I try to make an effort for the underside of the caras much as I do for the engine and body work and remove any rust ( if there was any lol ) and paint as required

 

Don't worry about it. It's only surface rust. It would take YEARS for any substantial
rust to cause any problems. It's kind of up there with rust on the brakes.

However, you don't want rust on the CV joints, rust will do damage there from being
abrasive.

If you want to fix it. Sand the rust off, don't "chip" anything. Then use some rust proofing
primer, then paint em.

If the shafts rust threw one you, I'll buy you new ones.

 

Ill go half and half with you.
If you really want to you could go thru the trouble of repainting them but it would probably take 30 years to rust to the point of breaking the shaft.