There is no doubt that, eventually, everything will break. Practice
shows, however, that the same functional parts, made by different
brands, have different life spans under the same working conditions,
which can be explained by design (heavy duty vs medium duty) and
material quality (steels and alloys) used during production. Of all
hydraulic pump and motor brands that passed through my hands, one brand
has always stood out, showing a particularly superior quality of
components - the Linde. Despite of most of the times ridiculously
over-engineered design, the essential parts, like pistons, cylinder
blocks, valve plates, swash-plates, etc.. have always presented precise
high quality machining combined with excellent material selection (most
probably the result of many weeks of thorough tribological tests),
something that resulted in over-priced spares but also long lasting and
reliable units. I am definitely not a "Linde" fan (with the exception
of their fixed displacement axial piston motors, which are next to
perfect, especially the newer series), but I admit that the quality of original parts
is extraordinary. However, even the best quality part has its breaking
point, the proof of which you can see on these pictures, showing a
damaged rotary group of a Linde BPV70 closed circuit pump which,
unfortunately for its owner, just couldn't pump it...
By the way, suspecting incorrect bearing play (the
shaft is suspended by two tapered bearings) I re-checked it and it was
OK, making overtorque the most possible cause of this malfunction.
