The first time it hung the rack it was partially my fault, I installed new delivery valves, and I unknowingly reused a non-reusable crush washer that they had installed under the delivery valves, the washer for some reason came off center and got crushed into a stepped frisby looking thing. The pump shop was able to replace one p&b and save the rest. I think the others weren't damaged but off just enough to hang. So far they took care of me on the last pump. Although that was just labor and one p&b, don't know if it's going to take all 6 now to make it last.
On edit: I'll point out that I ALWAYS remove the washers under delivery valves, that said when I changed delivery valves I didn't see any copper, I figured since I had 131 seats that they left them out. The new crush washers are steel and they blended in good enough I couldn't tell they were in there.