hayes disc brake install

[fondigley]

Recently purchased Hayes disc brakes hfx mags. Anyone know what the little tiny black rubber bushing/washer is for? Where does it go? By the lever or the caliper? 1st time build with disc brakes and any help would be greatly appreciated, since I bought my bike about a month ago and finally got all the new parts last weekend. Would love to get it rolling tonight, but want to make sure the build is proper.
Thanks

[fondigley]

here is a picture of the part i am talking about. I got word that it is not for the brakeline, but want to be sure.

[Dirty]

looks like an o-ring, if its rubber and flexible...
these are used to create the seal on the hardware that fixes the brake line to the caliper i believe...

[oldfart]

The photo looks like the "O" ring which seals the two halves of the caliper at the connection port. The brake line uses compression sleeves or olives which squeeze tight on the line around the barbed fitting at each end. Shimano use "O"rings about that size for their fittings. Did Hayes change their fittings?