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
