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Procedure #5 Spring Plunger adjustment and replacement
The spring plungers are located in the center of each rotating electrode hub cap, and are vital to maintain
good continuity through the coulter hub bearings. They are factory preset, and should not need routine
adjustment. If a continuity test shows abnormally high resistance, the plungers should be checked. This
may be performed in the following manner:
Front Turbo Coulter (electrode #1)
1) Check coulter hub bearing preload by grasping coulter blade and pushing from
2) Remove the 3/8" allen head set screw.
3) Remove the plunger by turning counter-clockwise.
4) Depress the spring-loaded tip on a hard surface to determine if
5) If the plunger will not move freely, replace. Coat the threads with di-electric silicone
6) If the plunger appears to be in good working order, reinstall in the hub, and adjust
7) Reinstall locking set screw and tighten firmly on top of plunger. The top of the
8) Re-test coulter electrode continuity
Figure 5.1
In some cases, you may have to remove the hub cap to service the spring plunger, if the
plunger is rusted in the cap, or if the readings are still unsatisfactory with the new plunger
installed.
side to side. If there is any noticeable movement, bearing preload is incorrect, or
bearings are failing --and this can damage the spring plunger; see procedure #8
for adjustment or replacement.
plunger has adequate tension and can move freely.
grease before installation.
until it bottoms against the spindle end. Rotate 1/2 turn backward to allow
adequate clearance. Improper adjustment will result in premature failure (too little
tolerance) or poor continuity (too much tolerance). See below to view proper
clearance.
setscrew should be even with the face of the hub. If not, remove and adjust the
plunger inward or outward as necessary.
6-8
Pub# OM22-iScan EC-OM
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