[1.4 AUA] Unusual () drive shaft failure

[Joakim]

Hallo

Entschuldigung, aber Ich glaube dass Sie mir besser verstanden ob ich in English schreibe.

 

I just had a failure with the propulsion of our 2001 Audi A2 1.4 AUA .

The car wont move by itself and this is the second time for me.

 

When I bought the car one year ago it had the same problem of not being able to move by itself, and the seller advertised the car as having a faulty gearbox.

But once home I could conclude that it was the left side drive shaft that had failed.

 

The particular failure mode was a first for me; it was the splines that attaches the outer joint to the shaft itself that had failed.

At closer inspection I could see that it was the splines of the shaft itself that had corroded som bad that it lost its mechanical connection with the inner splines of the outer joint, so it was just spinning when trying to transmit torque.

 

And now, a year later I suspect that the same thing has happened to the right side.

A video I just made:

https://youtu.be/PYj95qabnL4

 

Is this a common thing to happen? I havent read about anywhere yet.

 

 

[vembicon]

vor 31 Minuten schrieb Joakim:

Is this a common thing to happen?

 

No - it is not !!!!

My first assumption: 

1) Lack of special glue/seal within the connection of splines of the shaft and inner splines of the outer joint - which allowed water (salt?) to intrude or
2) Wrong length of shafts (!?)

[Joakim]

vor 6 Stunden schrieb vembicon:

 

No - it is not !!!!

My first assumption: 

1) Lack of special glue/seal within the connection of splines of the shaft and inner splines of the outer joint - which allowed water (salt?) to intrude or
2) Wrong length of shafts (!?)

 

1. I am not aware that any particular sealant should be used in that connection, should it?

 

2. You are right, drive shaft length could be one suspect, perhaps if the shaft is too short. Or has not been fully inserted in the outerjoint so the circlip engages.

I need to check this when I take it apart.

But from what I can see this is the original genuine Audi drive shaft, i.e. seems not to be a different shorter type.

 

Overall, seems this has not happened to any one else. Interesting  that it happens on both sides for me on this car.

 

[fendent]

I have never seen this. I suspect something regarding the noise. As vembicon already mentioned an issue with the length of the shaft comes to my mind as well. Or if you are "lucky" the nut that secures the shaft in the wheel bearing is lost and the shaft slipped out of the housing.
My advice for you is "simple". Inspect the car with a fellow A2 owner who knows the car well. From your description I assume you are not an experienced self help car mechanic.
The A2 is a solid car if maintained regularly and in case of an accident repairs were done according to the manufacturers instructions.
Your car seems to have missed care over the years as your description and video confirm.  An important question is how much are you willing to invest in repairs? Set yourself a firm limit before you invest 1 more €. The market has many similar cars to offer for less than repairs could cost. All A2 are at least 16 years old. So repairs are to be expected.

And most importantly: DO NOT DRIVE THE CAR NOW. It is not safe to drive.

[ThePurpleKnight]

5 hours ago, Joakim said:

1. I am not aware that any particular sealant should be used in that connection, should it?

The glue (some kind of threadlocker) is only used on the splines where the CV Joint is plugged into the hub. On the inside is only the circlip spring.

[Joakim]

vor 14 Stunden schrieb fendent:

I have never seen this. I suspect something regarding the noise. As vembicon already mentioned an issue with the length of the shaft comes to my mind as well. Or if you are "lucky" the nut that secures the shaft in the wheel bearing is lost and the shaft slipped out of the housing.
My advice for you is "simple". Inspect the car with a fellow A2 owner who knows the car well. From your description I assume you are not an experienced self help car mechanic.
The A2 is a solid car if maintained regularly and in case of an accident repairs were done according to the manufacturers instructions.
Your car seems to have missed care over the years as your description and video confirm.  An important question is how much are you willing to invest in repairs? Set yourself a firm limit before you invest 1 more €. The market has many similar cars to offer for less than repairs could cost. All A2 are at least 16 years old. So repairs are to be expected.

And most importantly: DO NOT DRIVE THE CAR NOW. It is not safe to drive.

Thanks Marcel. Driving the car is by obvious reasons not even possible.

As can be seen in the video the outer joint does not rotate when the shaft is, which I would say rules out the possibility that the joint is "slipping" in the wheel bearing.

Well, I am not unfamiliar to car repairs so this will get fixed on coming week for sure. Have actually already ordered an SKF drive shaft VKJC 5097.

[Joakim]

vor 11 Stunden schrieb ThePurpleKnight:

The glue (some kind of threadlocker) is only used on the splines where the CV Joint is plugged into the hub. On the inside is only the circlip spring.

Right, that is my view of things too.

[vembicon]

"... The glue (some kind of threadlocker) is only used on the splines ..."

 

My opinion:

Beware from covering the complete surface of shaft as the result might be the later impossibility to remove the shaft from the housing once more again ...

It should be sufficiant to put a ring of glue on the edge next to the possibly intruding water only.

I would never take the strongest glue ever - as the stability of mechanical connection between housing and shaft is not depending on the glue!

[Nagah]

That "glue" that is used from factory is not necessary for a proper transfer of power.

I always struggled a lot when trying to disassemble the driveshaft from the hub, hence I never replaced that "glue". Never had a problem.

 

Even now, while using much, much more torque & power with my 1.8T I never had any issues with that.

 

So your problem must either be "wrong hardware" or the previous owner did some SERIOUSLY sketchy stuff with that car.

My advice: Check if the driveshafts are really the correct ones for the A2, and if so, then replace hubs and outer bearings.

[Joakim]

I finally got around changing the drive shaft today.

I can confirm that my suspicions in my first post was correct; it was the splines that failed:

The splines between the actual shaft and the outer joint were no longer able transfer any torque.

I cant conclude the root cause in the same way as when this happened at the left side (this is now on the right side), when it seemed that corrosion had reduce the spline material.

 

detail video

 

Well well, it has now been replaced with a new SKF VKJC 5097 and the car drives fine now.

The new drive shaft was approx 0,9 kg heavier than the original one. Either thicker material or just homogenous shaft instead of hollow I guess.

SKF calls it OEM quality or something like that, but this is on the borderline I would say; my ALU car is now heavier .

 

[Nagah]

How are the splines in the hub?

[Joakim]

Am 8.8.2021 um 13:15 schrieb Nagah:

How are the splines in the hub?

Sorry, I missed your post.

You mean the corresponding spline inside the CV joint?

Not bad really. But I didnt reuse it as I bought a complete driveshaft.

Works well ever since.