9
GP7145(-SSP) and GP7255A(-SSP) Repair Instructions
TO CHECK VALVES
Loosen plugs (58), take out tension spring (57) and then remove the complete valve assembly
(#51 & 52) with either a valve tool or an M16 hexagon screw. Check sealing surfaces and replace
worn parts. The discharge valve seat (# 52E) can be used on both sides. If you re-use it, make sure
you switch the O-Ring (#51D) to the opposite side. Pumps manufactured after 10/07 are supplied
with valve assemblies which screw together. Check O-rings and support rings. Tighten plugs (58) to
107 ft.-lbs. (145 NM).
TO CHECK SEALS AND PLUNGER PIPE
Loosen nuts (49A) and remove pump head (50). Separate the plunger connection (36A) from the
crosshead (25) by means of an open-end wrench (size 36mm). Pull seal sleeves (39) out of their fit
-
tings in the crankcase (1). Take the seal case (38) out of the seal sleeve (39). Examine the plunger
parts (36A-36D), seals (42 & 39A) and O-rings (38A & 38B). When replacing the plunger pipe (36B),
tighten tension screws (36C) to 30 ft. lbs. (40 NM). Replace worn parts; grease seals with Silicone
before installing.
CAUTION:
Don’t loosen the (3) plunger connections (36A) before the valve casing has been
removed otherwise the tension screw (36C) could hit against the valve adapter (56)
when the pump is being turned. Seal life can be increased if the pre-tensioning allows
for a little leakage. This assists lubrication and keeps the seals cool. It is therefore not
necessary to replace seals before the leakage becomes too heavy and causes output
and operating pressure to drop.
MOUNTING VALVE CASING
Check O-rings (38A & 38B) on the seal case (38). Clean surfaces of seal sleeves in gear box and
sealing surfaces of valve casing (50). Push the valve casing carefully on the O-rings of the seal
case and centering studs (50A). Tighten nuts (49A) to 103 ft. lbs. (140 NM).
TO DISASSEMBLE GEAR
Take out plunger (36) and seal sleeves (39) as described above. Drain the oil. After removing the
circlip ring (33B), lever out seal retainer (33) with a screw driver. Check seals (32 & 33A) and sur
-
faces of crosshead (25). Remove the crankcase cover (4). Loosen inner hexagon screws on
the connecting rods (24).
Note:
Connecting rods are marked for identification. Do not twist connecting rod halves. Each con
-
necting rod is to be reinstalled in the same position (and orientation) on the crankshaft journals.
Push the connecting rod halves as far into the crosshead guide as possible. Check the surfaces
of connecting rod and crankshaft (22). Take out the bearing cover (14) to one side and push out
crankshaft taking particular care that the connecting rod doesn’t bend. Re-assemble in reverse
order. Regulate axial bearing clearance to a minimum of 0.1mm and a maximum of 0.15mm by
means of fitting discs (20A). The crankshaft should turn easily and with little clearance. Tighten
screws (24) to 30 ft.-lbs. (40 NM).
Important!
The connecting rod has to be able to slightly move sideways at the crankshaft
journal.
Important!
Seal (32) must always be installed so that the seal-lip on the inside diameter faces the
oil. Possible axial float of the seal retainer (33) should be compensated with the shims
(33C).
