I had this same problem with them in a set I bought in November. When I got time to put them on in December, I discovered the hose threads in the hole were wallowed out too much to tighten up the hose with out stripping the threads on the hose. The caliper was replaced with no shipping, but the car was down for a few more weeks until I had time again to finish the job. Fortunately, I had another Mercedes I was able to use.

W.