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July 8, 2011

Hydraulic Backpressure

Tractors today are becoming increasingly powerful with more and more hydraulic capacity, which is great for running all kinds of different implements or multiple machines at a time, allowing for better operations efficiency. But these big and powerful hydraulic systems come with one drawback, Back Pressure.

Back pressure occurs when hydraulic flow in the return line is restricted and causes a buildup of pressure backward through the line. This is undesirable as it robs the entire system of potential flow as the pump now has to produce more power to overcome the back pressure. Hydraulic motors in particular cannot handle excessive back pressure and will prematurely fail if exposed for any length of time.

There are a number of things we can do to reduce back pressure and increase the efficiency and longevity of our implements.


Free flowing return for hydraulic motors. Back pressure is most commonly caused by routing the return line back through the pump spool and valve block, this is very useful if we need to have double action (such as in a hydraulic cylinder) but not necessary for a hydraulic motor that is only turning one direction. by taking the return line from the motor and returning it directly back into a reservoir tank, we make sure that the hydraulic flow can return completely unrestricted.








Hose diameter can be a cause of back pressure. The longer the hose is, the more important it is to ensure it is the proper diameter for the amount of flow (not pressure!) it is required to move. Moving up a hose size can help to alleviate back pressure.






Quick couplers restrict flow because they have small orifices, use quick couplers sparingly or not at all if possible. Upgrading to a larger size quick coupler can also be helpful in reducing pack pressure. Another potential hazard associated with quick couplers is pressure spikes, if the coupler is not attached properly and becomes detached while the implement is in operation, a pressure damaging spike can occur.






Maintenance of the hydraulic system should be a part of your overall tractor maintenance program. Filters that are clogged not only are a source of back pressure, but  waste potential power. Worn and kinked hoses are plain dangerous.










Reducing back pressure will increase the life of your implements, reduce load on your hydraulic pump, and save your motor seals, o-ring, piston and scraper rings.