ENGINE AR 7E5078 - Caterpillar

Illustration 21 g02156363
Control valve boreDo not use again. If any scratches on the control valve bore catch a seal pick that is pushed across the surface, the valve body should not be reused. Refer to Illustration 21.If no excessive wear is found, use a suitable measuring device to measure the lands of the bores.
Illustration 22 g02156290
Measuring toolThe preferred method of measurement is to use an air gauge in order to measure the lands in each bore at three locations. The measurements should be taken 120 degrees apart.Use the dimensions listed in Table 3 to determine if the part can be reused.
Table 3
Bore Dimensions    
Bore     Diameter    
Rotary selector spool    
34.930 0.015 mm (1.3752 0.0006 inch)    
Relief / neutralizer valve    
28.580 0.015 mm (1.1252 0.0006 inch)    
Priority reduction valve    
25.400 0.015 mm (1.0000 0.0006 inch)    Rotary Selector Spool (25)
An earlier version is pictured. Later spools have balance grooves between each row of holes. Both versions can be used again.The grinding method used can cause the spool to appear to have been cam ground. Spools with this type of appearance can be used again.Note: Be sure to clean the filter inside the selector spool (refer to Illustration 18) before assembling the valve group.
Illustration 23 g02156994
Rotary selector spool (29) Cam-ground appearance (A) Charge end of spoolUse again. If there are no scratches that catch a seal pick, the spool may be used again.Do not use again. If scratches on charge end of spool catch a seal pick that is pushed across the surface, the spool should not be used again.Drive Pin (26)
Notches or grooves, on the pin head and shank (near the end) usually appear early in pin life. This condition will stop as the pieces "wear in", providing a larger contact area.The pin must fit tightly into the bore of the rotary selector spool. If loose, the pin can move out of place and drag on the bore of valve body causing a shifting problem.Push against the drive pin, if drive pin is fits tight in the bore of the spool, use spool assembly again. (Do not press the pin out of the bore.) If drive pin is loose in the bore, a new pin should be installed. Use a new spool assembly, if the bore in the spool assembly has been damaged and a new pin does not fit tightly.
Illustration 24 g02156995
Drive pin (30) Acceptable groove (31) Acceptable notch (32) Not acceptable notchDo not use again. If, the notch in central part of body could cause the pin to break.Rotary Actuator Group
Illustration 25 g02156996
Rotary actuator group (33) Actuator vane (34) Shuttle valveRotary Actuator Vane
Notches or grooves in the drive pin slot for the rotary actuator vane usually appear early in the service life of the part life. As the pieces "wear in", the notches do not increase and provide a larger contact area.
Illustration 26 g02156998
Rotary actuator vane (35) Wear notchesUse again. Notches in the rotary actuator valve are acceptable.Inspect the