ST-4125D/ST-6125D — MAINTENANCE
LUBRICATION
To check the oil level of the mechanical seal perform the following:
1.Lay the pump (Figure 17) on its side with the oil plug facing upwards.
2.Remove oil fill plug.
3.Visually inspect oil plug hole to verify that oil cavity is full enoughtocoversealspring.Checkevery300hours,change hydraulic oil every 6 months (1,000 hours) or as needed.
4.While checking the hydraulic oil level, also check the condition of the hydraulic oil in the seal cavity . Block the opening with a finger and roll pump to one side to drain oil into a small transparent container.If oil is cloudy or has water in it, drain oil from pump cavity and replace hydrau- lic oil. Check the seal for wear damage.
5.If oil level is low fill with SAE 10 weight
IMPELLER
1.Make sure the clearance between the impeller and the friction disk is approximately .012
2.Ifimpellerisdefectiveorbadlyworn,replaceimpellerimme- diately.
LAY PUMP FLAT
ON ITS SIDE
REMOVE FILL PLUG, AND VISUALLY INSPECT THAT OIL CAVITY IS FULL ENOUGH TO COVER SEAL SPRING. 
FILL TO
FILL WITH 10 WEIGHT NON- DETERGENT HYDRAULIC OIL. USE SHELL TURBO 32 OR EQUIVALENT.
CHECK HYDRAULIC OIL EVERY 300 HOURS. CHANGE EVERY 6 MONTHS OR AS NEEDED.
Figure 17. Checking Hydraulic Oil
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