Hercules GTA4800 — Water pump rebuild

Repair & overhaul

For the Hercules GTA4800, from the Hercules service manual.

Applies to: Hercules G4800 series engine

Procedure

1. Remove dirt, dust or foreign material from body and housing before disassembly.
2. Remove screws and washers from housing flange; remove housing assembly from body; discard gasket.
3. Remove pulley from drive shaft with gear puller or arbor press.
4. Remove snap ring from housing assembly; do not hammer or pry impeller.
5. Place housing assembly in arbor press with impeller facing up; press impeller shaft through impeller and from housing.
6. Remove and discard seal assembly, impeller shaft seal, and shaft.
7. Clean pulley, housing, and body thoroughly in solvent; dry with compressed air.
8. Inspect pulley, body, housing for cracks, worn threads, oversize bearing bore.
9. Lubricate bearing bore and impeller shaft; press impeller shaft into housing.
10. Install snap ring; install seal over shaft and press into housing.
11. Lubricate shaft and install seal assembly with ceramic side toward impeller shaft seal.
12. Coat impeller shaft with Loctite grade 601; press impeller onto shaft to 0.100 inches clearance.
13. Roughen drive shaft; coat pulley bore and shaft with Loctite grade 601; install pulley with arbor press.
14. Spin impeller by hand; check no contact with housing.
15. Install gasket and housing assembly on body; align holes and install screws; tighten crosswise to 16 ft-lbs.

Source: Hercules service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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