Finish Thompson BE-55C - Manual (Page 33)

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PUMP AND MOTOR DISASSEMBLY:
1. Set the pump and motor assembly onto the motor fan cover so that the pump is facing upright on
the workbench.
2. Remove the five socket-head bolts that hold on the pump’s housing and remove the pump housing.
The nuts for the bolts are recessed into the tabs of the motor adapter. Also remove the housing o-
ring.
IMPORTANT: Take note of the orientation of the pump’s discharge (where the elbow is attached) to
allow proper reassembly after repairs.
3. Turn the pump’s impeller until one pair of the impeller shaft’s set screws become visible through the
slots in the motor adapter. Loosen that pair of set screws, then turn the impeller again to locate and
loosen the second pair of set screws.
4. Pull the impeller and impeller shaft away from the motor’s shaft (an assembly of the impeller,
impeller shaft, housing cover, and seal will be removed together).
NOTE: The impeller shaft may be difficult to pull loose from the motor. Attempt to pry on the base of the
impeller shaft with a flat screwdriver through the slots in the motor adapter. Take care to not damage
any pump components while prying.
5. Loosen the four socket-head bolts to remove the motor adapter and motor from the motor mounting
plate.
6. Inspect all parts and replace any parts that appear worn, melted, or corroded.
PUMP AND MOTOR REASSEMBLY:
1. Bolt the motor and motor adapter to the motor mounting plate using the four socket-head bolts.
2. Coat the motor’s shaft with an anti-seize compound. Install the impeller, impeller shaft, housing
cover, and seal assembly onto the motor shaft. DO NOT tighten the impeller shaft’s set screws at
this time.
3. Place the housing o-ring into position on the housing cover. Bolt the housing cover into position
with the pump’s discharge in the same position as it was originally. The nuts for the bolts will insert
into the tabs of the motor adapter.
4. Set the gap between the impeller vanes and the inside of the housing cover to the proper tolerance.
Insert a .020” feeler gage into the suction of the pump’s housing (remove the suction screen if so
equipped). Position the feeler gage on top of one of the impeller’s vanes. Pry up on the base of the
impeller’s shaft (use a flat screwdriver through the slot in the motor adapter) until the feeler gage is
sandwiched between the vane and the housing. Tighten the four set screws in the impeller shaft,
and remove the feeler gage. Re-insert the suction screen (if equipped).
IMPORTANT: It is critical for performance that the gap between the impeller’s vanes and the inside
of the housing cover be set to the proper distance. A gap of .020” +/- .005 is required.
Re-install the pump and motor as outlined in the preceding section, “Pump and motor removal and re-
installation”.