Hydraulic filter elements divide into two main categories: surface and depth. Surface filters typically have a wire mesh construction like, for example, a suction strainer. Depth filters are constructed from a matrix of fibres. Cellulose (paper), plastic, glass and metal can all be used to construct a depth filter.

Man-made glass fibers are smaller and more uniform than naturally occurring … Read more

A new client consulted me about the hydraulic oil turning black, smells bad and is depositing varnish in the Hitachi EX5600 excavators he is responsible for. These are BIG diggers. Twin Cummins QSK50s with 4 main pumps (250 GPM) on each engine. Bucket capacity is 40 tons. And a 240 ton dump truck is loaded in 6 passes, in around … Read more

One of our members wrote me with this question:

“On Cat diggers and some other makes they have two hoses off the pumps that are plugged. I call them hoses to nowhere. Some mechanics have told me they are there to reduce spike pressures. And others have said they are to make the pumps run quieter. Can you please tell … Read more