Giant REPAIR INSTRUCTION - LP121HT PUMP, To Check Valves, To Check Seals and Plungers

REPAIR INSTRUCTION - LP121HT PUMP

To Check Valves

Loosen valve plugs (48). Either with needle nose pliers or with a M12 screw, which can be threaded into the hole of the spring retainer (46D), take out discharge and inlet valve assemblies. Press onto the valve plate (46B) and twist to take apart the valve assembly. Check and replace worn parts. Tighten the plug to 107 ft.-lbs.

To Check Seals and Plungers

Loosen the eight nuts (49A) and take off the valve casing (43). Remove the seals (40) on the valve casing. Take seal sleeve (35) out of the guides in the crankcase (1) and remove the leakage seals (36).

Check plunger pipes (29B) for damage and remove any dirt. When replacing plunger pipes, use new copper rings (29D). Apply loctite on threads of plunger bolts (29C) and tighten to 33 ft.-lbs.

Check seals and replace as necessary.

Place new v-sleeves (40) along with support rings (41) in the valve casing (43). Place seals (36) and pressure rings (39) in seal sleeve (35). Install the complete unit in the valve casing. Finally, fit in the complete pump head assembly carefully over the plunger pipes and evenly tighten nuts to 59 ft.-lbs.

To Dismantle Gear End

After removing the valve casing (1) and plunger pipes (29B), drain the oil. Take off crankcase cover (4) and bearing cover (14). Loosen connecting rod screws (24) and push the connecting rod/plunger base assembly forward (as far as possible) into the crosshead guides. Caution: Connecting rods are marked for identification. Do not twist connecting rod halves. Connecting rods are to be reinstalled in the same position on the crankshaft journals. Turning the crankshaft (22) slightly, hit it out carefully to the side with a rubber hammer. Caution: Do not bend the connecting rod shanks. Check crankshaft and connecting rod surfaces, shaft seals (15) and taper roller bearings (20).

To Reassemble

Using a soft tool, press in the outer bearing ring until the outer edge is aligned with the outer edge of the bearing hole. Take off bearing cover (14) together with shaft seal (15) and o-ring (16). Fit crankshaft (22) through bearing hole on the opposite side. Press in outer bearing and tension it inwards with the bearing cover (keeping the shaft in a vertical position and turning slowly so that the taper rollers of the bearings touch the edge of the outer bearing ring). Adjust axial bearing clearance to at least 0.1mm and a maximum of 0.15mm by placing fitting discs (20A and 20B) under the bearing cover. Caution: After assembly, the crankshaft (22) should turn easily with very little clearance. Tighten connecting rod screws (24) to 310 in.-lbs.

NOTE: Contact Giant Industries for Service School Information. Phone: (419)-531-4600