VALVE AS-CHECK 2479730 - Caterpillar

Dial indicator and contact point.The earlier 3P1567 Dial Indicators did not have a return spring, (but return springs have been added to many of these indicators). The total measurement range for the earlier indicator is approximately .8" (20 mm). The 5P6531 Contact Point is 2.25" (57.2 mm) long and is used with the earlier indicators either with or without return springs.
The later 3P1567 Dial Indicators have a return spring. The total measurement range for the later indicator is approximately 1" (25 mm). The 5P4809 Contact Point is 2.00" (50.8 mm) long and is used with the later indicators.
Since the return spring is not a good identification of earlier or later types, it is necessary to measure the dial indicator with the contact point installed. See dimension A in the illustration. If the correct contact point is used, dimension A will be approximately 3" (76 mm). If dimension A is not approximately 3" (76 mm), the wrong contact point is used.
When the dial indicator and contact are installed in the fuel system and the large hand of the indicator is to be put on zero, be sure the indicator is not moved down more than .08" (2 mm) which is two revolutions of the large hand from the free position (no force on the contact point).