UrS4boy

The front crank seal (aka "radial shaft seal") PN is 054115147B. (Item 2 below). This 35 x 48 x 10 seal is very very common in the older Audi line from 1977 to at least 2005. It was used on 4, 5, 6 and 8 cylinder engines. Specifically, it is the same crank seal for the 3B, AAN, ABY and ADU (and the ABH V8 in my 94 S4 V8 avant and the AHK in the S6Plus).



These seals are not expensive, e.g. US$14 for a new OE seal. Search SiteSearch 054115147B - 054115147B - Front Crankshaft Seal - ES#260046

Front side:



Back side:



To get at the crank seal, you need to remove the crank sprocket so you might as well do the 20VT timing belt while you are there. (More commonly, you are already doing the timing belt and discover that the seal is weeping). I replaced the front crank seal because in 2010 I was doing the 2nd timing belt during the ownership of my 93 UrS4 (since 1998) and decided that I would replace the seal as a precaution/preemption against future leaking.

Removed my crank seal with the proper crankseal tool (borrowed):



I didn't have the proper install tool (expensive) and didn't have a 35 mm (??) socket to tap the new seal home so I went to RONA (like Home Depot) and bought a $1.50 1.5" ABS threaded cap and once I got the seal started by hand, used it and a hammer to tap the seal home. Here is the cap sitting on another crankseal (054115147B, 35 x 48 x 10):



The hole in the top of the cap was created to use the new crank bolt to pull the cap against the seal and push the seal in. However, as I applied more pressure, the crank moved (gave me a bit of a scare). I stopped and went back to the tapping method. Fortunately, I foresaw the potential for the crank to move and had marked on the oil pump where the keyway was on the crank. Remedy was to put the crank pulley and harmonic damper back on the crank and rotate the engine back the few degrees that it had moved (fingers crossed I didn`t scare a valve).

It was all fine. Engine is fine. Seal is fine 4 years later.

Hope this helps.