[GV27]

I'm 98.873% certain that a cap for a 2005 Audi A4 will fit. When I had mine I used the exact same basic "european" adapter I have for my Motive power bleeder for both cars. From AutohausAZ you have to buy the reservoir to get the cap but it's not super expensive (cap is, unfortunately, yellow however):

Metzger 8E0611301G, 2140145 Brake Fluid Reservoir - Audi, VW | 8E0611301C 8E0611301E

Find Metzger, 2140145 Brake Fluid Reservoir 8E0611301G at discount prices in our extensive Audi, VW auto parts catalog. AutohausAZ offers a large selection of Metzger parts online. Fits Audi A4 Quattro, A6 Quattro, A4, S4, A6, VW Passat. 2140145 8E0611301C 8E0611301E

www.autohausaz.com

Here's what Motive has to say on the subject:

Nearly every European made car can use the 1100 and 1109 caps that are included in the 0100 and 0109 kits. These caps are female threaded caps and have an inner diameter at the threads of 45mm. BMW, Porsche, Saab, Volvo, VW (except air cooled) have used this type of cap since the late 1950s. Most other european cars also use this cap with some exceptions. Ferrari on some models and years will use a slightly smaller cap that is 42mm inner diameter. If you have a European made cars with a female threaded cap will more than likely use the 1100 and 1109 caps, but please check the inner diameter of the cap to be sure.

 

[GV27]

edit: Ah never mind. What's the use. I'll just get banned again.

PM me - I can tell you which one to get an Autozone, Advance, etc. They all have it in stock in my neighborhood.