HELP! I have a customer with a C500s60 355-1204-4046 don't they make good inching slave cylinders for these anymore or what??? I've replaced many of these with no problems but here's the story for this special piece. First was just a normal replacement it lasted about 4 months and I figured must have been a small defect no big deal so I replaced it again. Next he calls back 1 month later same problem so I figure out that the seals are shrinking and check around and find the old style piston and cup and install it. He calls back 2 weeks later same problem inching master cylinder is dry and has leaked out of the slave cylinder so I inspect it and find the side is wore off the piston cup. By now I have called some manufacturers to see if I can get a better material to no avail so after doing a little more research find that there should be a spring and cup centering plug so I installed this with all new parts again but 2 weeks is all it will last. Anybody have a better solution than dynamite!!!