Archive | April 4, 2014

Rebuilding Stainless Steel Hydraulic Cylinders – Galling Problems

Welding stainless steel cylinders

Welding stainless steel cylinders

We recently took a pair of stainless steel hydraulic cylinders off a swim platform on a hauled 130’ vessel Sunseeker. The cylinders needed to be rebuilt due to leaking hydraulic fluid. Rebuilding a cylinder is typically a fairly straight forward procedure, usually a few hours of shop time, when it is done right the first time.

Stainless steel hydraulic cylinders have a threaded stainless steel cap that is subject to galling and seizing during disassembly, if not probably lubricated with an anti-seizing agent the first time. Galling is caused by a combination of friction and adhesion between the surfaces, followed by slipping and tearing of crystal structure beneath the surface. This will generally leave some material stuck or even friction welded to the adjacent surface, while the galled material may appear gouged with balled-up or torn lumps of material stuck to its surface.When galling or seizing takes place, it becomes necessary to cut the barrels off the shafts of the stainless steel hydraulic cylindersto cut away the threads that are “welded”. This will result in many hours in the machine shop and extend the job and cost from a simple procedure to a much more time and money consuming process.

At times, the cost to custom machine and repair exceeds the cost of a new replacement. However, lead times and schedules often make the “repair vs. buy new” decision.

The moral of the story – be prepared for higher costs and longer delays getting back in the water if your stainless steel hydraulic cylinders are not done right the first time.