I like my Tassimo but after using it for about a year I discovered that the rubber on the piercing unit wore out and eventually came off completely. This rubber seals the t-disk to the piercing unit so without it the coffee maker is almost useless because it makes a huge mess. I found that replacing the original rubber with rubber “o” rings from the hardware store saves having to buy a new piercing unit, that has to be ordered online for $10.00 + $8.95 shipping. That's $18.95! Hello Tassimo, I could buy a new Mr. coffee pot for that price..... Anyway, here's my fix, I hope this is helpful. BTW, this is my first instructable.
Step 1: Remove piercing unit
Step 2: Buy "o" rings
All I did was match up the rings they have there with the piercing unit that I brought into the store. Maybe you can find a better match.