It seemed fine ,that is the roller coaster piece ,the piece that lost the battle was the tappet ,it had a nice groove being made ,if driven another few weeks it would have surely sent those parts into the chain.My guess would be 140 miles I had put on it till I got back from my road trip ,it still made vacuum so dont feel that its not the culpreit because of this sign.Their is some detail also to be aware of on the vac pump , the allen bolts ,when pulling the unit it will give you false hope that you can use a socket on all the bolts ,the clearance on a few will only allow for the L shaped allen due to clearance.