Toro Groundsmaster 328-D, Service Manual

Page: 60 / 402

Oil Pump Servicing
The oil pump is a trochoid gear type pump, mounted to
the rear of the fuel injection pump, and driven by the fuel
injection pump camshaft. The pump houses a check
valve which opens to the oil pan when the pump delivery
pressure exceeds 57 psi (393 kPa), thereby preventing
excessive oil pressure.
Disassembly of Oil Pump (Fig. 29)
1. Drain the engine oil.
2. Remove the oil filter. The use of a filter wrench may
be necessary.
3. Remove the four bolts which hold the pump cover in
place and attach the pump to the cylinder block.
4. Remove the pump cover, body and rotors and gasket.
Oil Pump Inspection (Fig. 30, 31, 32)
The oil pump, or its worn components, should be re-
placed when internal pump clearances exceed those
shown in the table above.
1. Outer Rotor to body clearance should be checked
with a feeler gauge. If clearance exceeds the service
limit, replace the rotor assembly.
2. Outer rotor to Inner Rotor clearance should be
checked with a feeler gauge. If clearance exceeds the
service limit, replace the rotor assembly. Check the
coupling end of the Inner Rotor shaft for cracks or
damage.
3. Rotor to cover clearance should be check with a feeler
gauge by placing the rotor assembly in the pump body
and using the cover as a straight edge.
In case of excessive clearance, replace either the Rotor
Assembly or the Oil Pump Body.
4. Inspect the Pump Body 0-ring for cuts, cracks or other
damage.
5. The Pump Relief Valve can be disassembled by
removing the plug, gasket, spring and plunger. Ensure
that the Relief Plunger travels freely, and that the drain
holes in the Plunger are not blocked.
Figure 29
Figure 30
Figure 31
Figure 32
External Engine Component Repair Page 4 - 30 Groundsmaster
®
300 Series