I used this tool for approximately 30 copper crimps; all either 3/4" or 1", before it began failing to complete a successful crimp. It appears that it is not holding pressure even though I do not see any fluid leaks from the tool. I can pump it up even without the jaws attached and watch it slowly retract from the fully pumped position. When trying to crimp, it will not hold enough pressure to successfully crimp a fitting without the fitting leaking.