Wear Test
NOTE:
Before disassembling distributor, make a wear test to determine if bushings and shaft require replacement.
Remove rotor, disconnect primary lead but do not loosen breaker arm contact spring retaining nut. Clamp ribbed section of distributor housing in a soft jawed vise and mount a dial indicator plunger arm resting against movable contact arm at the rubbing block, with rubbing block on high point of cam lobe. Engage wire loop on distributor shaft above breaker cam and attach spring scale to loop so that pull can be applied in line with dial indicator plunger movement. Apply 5 lbs. pull on spring scale and note dial indicator reading. If shaft movement exceeds 0.006", replace distributor bushings and shaft as required.