The front suspension of the B5-chassis A4 is a bit unusual,
and that’s probably a charitable way of putting it. Primary among its goofy characteristics is an arrangement of two separate upper control arms to form the upper arm or wishbone. Each of these arms has a ball joint at its outer end. These two ball joints fit into holes at the top of the upright and are held in place by a inch bolt.
The pinch bolt is a source of frustration to almost everyone who works on these cars. They are prone to corroding in place, which can cause the bolt to break during its attempted removal. I thank my lucky stars that when working on my Minnesota car, a prime candidate for a difficult pinch bolt, it came off without a hitch. It’s a great idea to hit your pinch bolt with a liberal application of penetrating lubricant well before you try to remove it. Spray both the nut and bolt ends, as well as the small gap between the ball joints.
You’ll note in the photographs that I have already removed the spring and shock assembly. You can remove the upper mounting plate, control arms, and spring and shock assembly all at once if you wish. The only real difference is whether you remove the two nuts holding the top of the spring/shock assembly to the upper mounting plate while it is in the car or after it is out of the car. If you remove the whole assembly, you can avoid having to remove the two rubber plugs in the engine compartment above those nuts.
Some of the steps and photos in this project are the same as those in the Front Springs and Shocks project. Reference that project for additional information about the front suspension, particularly if you plan to change the springs or shocks along with the upper control arms.
This is the dreaded pinch bolt mentioned earlier. I’ll pointing to the nut on the forward side of the bolt. This long nut and bolt help hold the ball joints at the ends of the two upper control arms in place by pinching that portion of the suspension upright. Many people have reported that this bolt is difficult or impossible to remove, particularly when corrosion is present. A soaking in penetrating lubricant should help. It’s a good idea to have a spare pinch bolt prior to removal just in case it is damaged when removing. m8 bolt dimensions