How do I check brake fluid level on a 2005 Audi S4?

There's no dipstick under the cap, just a rubberized filter. Any ideas?How do I check brake fluid level on a 2005 Audi S4?try googleing it. or how bout calling the dealer?How do I check brake fluid level on a 2005 Audi S4?fill it to the top and you will be good. just dont let it run low or you will have to bleed your brakes