I have a 1998 Audi A6 Quattro wagon with C4 chassis on which the right front plastic jack socket, 4A0803855, exploded from the force of being jacked. The floor jack has an adapter with a smooth 5/8" round x 2" long steel piece going in to the plastic jack socket.

 

I finally got arround to removing the part of the broken plastic jack socket from my 1998 Audi A6 Quattro wagon with C4 chassis which did not fly off. It was only held by one very small flat head screw at the center. Other than this screw there are two plastic pins on the plastic jack socket, which go in to holes in the car. This plastic part is not even solid, but is hollowed out to be cheaper.
So, beware of jacking the car without the wheels on, as this plastic jack socket may pop without any warning! So, when you change a flat tire you need a jack stand!
Why is this part made without any steel reinforcement?

 

Thats the Germans.. over engineered in some areas, cheap crap in others.

Besides, which self respecting new Audi owner would be caught actually changing his own tire??

 

I wasn't changing a tire! I was trying to change my Audi and she snapped!

 

That was satirical... as in Audi doesn't think people who buy their car's will actually do the maintenance....

 

Most of those people loose a lot of money, because a poorly maintained car is worthless. However, if you look closely, you will find a few that are not completely ruined for about $3,000 or less, which just need minor repairs, such as replacing leaking seals and changing the ATF.
However, Audi is not alone. Apparently, Sony has laptop batteries which catch on fire or explode. So, having a jack socket expode seems normal. The big companies just keep making cheap non-reusable parts to boost the economy.
The parts seem to be made to fail, so that they may sell an expensive replacement.

 

That's me except for changing the ATF. Find a good cheep one and drive it forever.

As for the jack pad... There is no reason for the pad to have anything but compressive forces unless you fail to chock a wheel. If you don't you get exactly what you deserve... I usually use a substantial floor jack and don't ever get under a vehicle unless it is on jack stands. (notice the period) Good ones not cheepies.