Good Records = Good Maintenance

hydraulics manualsNumber 26 in 132 Cardinal Sins of Hydraulics I put together several years ago is: ‘Failing to properly document hydraulic system performance tests for evaluation and future reference.’ And #96 is: ‘Failing to properly document past problems and their solutions, along with machine repair history.’

When a hydraulic machine has a problem, good historical records can be just as valuable, and in some cases more valuable, than an accurate schematic diagram. Past performance isn’t always an indicator of future performance. But it’s great to know. Because it can save you from having to ‘reinvent the wheel’. If you’ve read The continue reading »

When Is It OK For a Piston Pump NOT to Have a Case Drain?

IM000260A repairer rebuilt a hydraulic piston pump. A week later it came back like a boomerang, the subject of a warranty claim. Upon tear down the piston retaining plate was found to be broken–see inset pic. Fearing the aftermarket parts they used were not up to scratch, the repair shop quietly accepted warranty and rebuilt the pump for a second time-using genuine parts.

About a week later the boomerang came back (again!). Similar mode of failure: cracked/buckled piston retaining plate. Can’t blame the gray parts this time. Since this type of damage is consistent with high case pressure–see page continue reading »

The SAFE Maintenance Imperative

big question markIn chapter 13 of The Hydraulic Maintenance Handbook I discuss in detail the elimination of problems by engineering them out. An obvious example of this strategy is, if a hydraulic system has taper thread adapters, their replacement with a more reliable type of connector eliminates the possibility of recurring leaks. Job done. And if an oil to water heat exchanger isn’t used, water can never contaminate the hydraulic fluid. Or if a suction strainer is discarded, it can never clog and destroy the pump. And so on.

Importantly, none of the above types of modifications can be regarded as a … continue reading »