When hydraulic systems started to appear on agricultural equipment, manufacturers published service manuals with pictorials showing how each system operated. Pictorials do not work well with modern machinery because:

•There too many hydraulic components on current agricultural machinery to be drawn in this style•Each pictorial needs to be duplicated several times to show how the components work in all working conditions and positions•The required text to describe how the system operated needed to be translated for technicians around the world

The ISO schematic to the right represents a hydrostatic drive system similar to the text and pictorial above. A technician can use the drawing to the left and fully understand how the system works.

The manufacturer’s explanation of how a hydraulic system functions can be done is a variety of ways:

•Pictorial (above)•Text (right)•ISO Schematic (bellow)

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Bobcat Hydraulics Manual

International Harvester 715 Combine Service Manual

International Harvester 715 Combine Service Manual

All students in Basic Hydraulics class are required to draw an ISO schematic for the Lego pneumatic backhoe shown above. The project works very well in having the students think about how individual components work together as a system.

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Applications:

Student Examples:

The schematic to the left is for the school-owned Challenger M535B agriculture tractor. After drawing schematics with ever increasing difficulty, they are able to use the schematic for troubleshooting exercises in their laboratories. (Only 1/3 of the tractor’s hydraulics are displayed here)

Challenger M535B Service Manual

Student inspects hydraulic bale tensioning system, bringing schematic reading skills to the field

Example of a student drawn backhoe schematic

Students working together on their term project. The assignment is to draw a complete ISO schematic for an actual piece of machinery.

School-owned Challenger M535B Agricultural Tractor