SPRING 1922081 - Caterpillar

Caterpillar Machines So EquippedWhen hydraulic pumps are installed on Caterpillar machines, it is important not to force the pump into position. When input splines and pump shafts are out of alignment, stress loads are put on the internal components. This can cause pump failure.
Gear-type pumps that have had this type of problem will usually have a large groove worn into the brass pressure plate at the rear of the drive gear. Special Publication, "Diagnosing Tyrone Gear Pump Failures," Form FEG45137, has complete information on failures of this type. On a vane-type pump the shaft bearing will usually break if alignment is bad.
Make sure the pump housing flange fits evenly against the machined surface before the pump is fastened in position. Any debris or rough places between the pump flange and the machined surface must be removed.
Also, the pump housing must not come in contact with other components during operation.
If there has been a problem with pump failure on a machine, use the procedure which follows to see if wrong installation of the pump is the cause.
1. Check the end of the pump shaft. A shiny area on the end of the shaft is an indication the pump shaft is not in full alignment with the drive splines.2. If the splines on the end of the pump shaft are too short or not machined correctly, do not install the pump. Check the part number of the pump to be sure you have the correct pump.3. If there is a shoulder or step between the spline and the seal surface on the pump shaft, make sure the shoulder does not prevent a correct fit between the pump drive and the pump shaft.4. If you have any questions about how parts are to be machined or dimensions of parts, your Product Analyst in Service Engineering.