Generac — Oil Pump with Oil Seal Assembly Removal and Installation
Repair & overhaul
From a Generac service manual covering: CAC478, CAC480, SQR480. Check it applies to your exact model before use.
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Procedure
- Loosen six M6×30 hexagonal flange bolts and remove the oil pump with oil seal assembly.
- Pry out the front crankshaft oil seal with a screwdriver or chisel without damaging the bore.
- Remove seven M6 countersunk head screws and remove the oil pump cover.
- Take out the inner and outer rotor.
- Check outer rotor to case bore clearance (0.06—0.19mm), inner to outer rotor radial clearance (0.05—0.18mm) and rotor end play (0.014—0.100mm).
- Remove the hexagonal socket head plug and take out the relief valve spring and plunger.
- Install rotors with installation marks upward.
- Install the oil pump cover and tighten seven screws to 79 in-lbs.
- Install relief valve and spring; screw the 3/8 in plug to 17 ft-lbs.
- Install new oil pump gasket, install pump, tighten retaining bolts to 89 in-lbs; press in front oil seal.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Oil pump cover screws: 79 in-lbs
- Oil pump retaining bolt: 89 in-lbs
- Relief valve plug 3/8 in: 17 ft-lbs
Source: Generac 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.