Our C4 UrS4 and UrS6 cars use a modified Macpherson strut suspension. While not as compliant as the multilink C5 suspension, the C4 suspension is much simpler and less costly to repair. As these C4 cars age, they need their front suspsension parts replaced, particularly the lower control arm with its two bushings and ball joint (not available separately) (Item 1 below) and the strut support ball bearing (Item 32 below) and the upper suspension strut bearing (called by many "upper strut mount")(Item 36 below). When aftermarket lowering springs are used, the concave support (Item 33) may have to be modified if opening the slots in the strut bearing ("upper strut mount") (Item 36) does not work. Anyway, here are a list of the parts:



Note 1: Item 10 "Sleeve" needs to be R&R'd when changing the lower track control arm - otherwise the bushing at the body end of the control arm will wear prematurely. Your's might not want to be removed. Two tricks: thread in a wheel bolt and pull or thread in a suitably sized tap and pull. If they are too badly rusted, you will need new ones (note the new ones are oval so once you press them in, they will stay).

Note 2: Item 14, the pinch bolt that holds the bearing housing to the ball joint (and vice versa): The 93 UrS4 PN is N0104457 = M10x45x20 (which I interpret as M10 thread, 45 mm long, 20 mm of which is threaded (= 25 mm shoulder). The UrS6 Item 14 PN is N0347784 = M10x50x24 = M10 thread, 50 mm long of which 24 mm is threaded, leaving 26 mm shoulder = effectively the same as the UrS4 bolt, only slightly longer threaded bit. YMMV

Here is what the proper and improper pinch bolts look like:





*NOTE: the stock shock (Item 43) for the "AAN Sport Suspension" is "031K"

As you can see, I skipped item 18. This is because the listing is long. However, here are the pertinent AAN-engined C4 numbers:



The factory springs were the lowest and stiffest in the 92 spec cars. In North America, the springs got softer and taller after that. Here is a post regarding comparison of 92 spec springs to Euro Springs.

Aftermarket springs are available from H&R and K&W and Intrac. Eibach used to make a spring for the C4 AAN UrS but they don't anymore.(LINK to Eibach Info) The Eibachs didn't drop the car as much as say the H&R springs. The good news was aligment specs could be attained by slotting Item 36. For H&R springs, you typically need to modify the Item 33 concave support to create so-called "Igor" plates (named after Igor Kessel who figured it all out).(LINK to Igor's instructions - with alignment specs)

Alternatively, you can buy fully adjustable camber/caster strut bearings from 2Benett and AMD Motorsports

Changing springs typically requires removal of the front struts (Some have done it without complete removal following Zwoobah's lower strut ball bearing procedure (see below). Here is one DIY for one Strut Removal Procedure

Removing and replacing the OE lower strut (ball) bearing (Item 32) can be done without removing the strut, as Zwoobah (Mike) described HERE

Here is what failed upper strut suspension bearings ("upper strut mounts") look out of the car:


Photo courtesy of Chapel

H&R makes both "sport springs" and "race springs" for our cars.
Shocks are a matter of preference but Bilstein seems to be a good choice. (I have the original Eibach UrS springs and Bilsteins - must be a good combination - great on the highway, sometimes too stiff in town, sometimes to soft on very undulating roads).