Giant GP7122, Operating Instructions Manual

12

7)  When reassembling: The inlet valve seat (51C) is 1mm 

smaller in diameter than the discharge valve seat (52C). 

Inlet valve seats are marked “S” and always have to be 

installed first. Discharge valve seats are marked “P” and 

are always to be installed on top of inlet valve. Plugs (58) 

are to be tensioned down evenly with screws (58C) and in 

crosswise pattern at 155 ft.-lbs. (210 Nm).

GP7122 REPAIR INSTRUCTIONS

11)  By  gripping  hex  flats, 

separate  plunger  (36) 

from crosshead (25) by 

means of two open-end 

wrenches (size 22mm 

and 27mm).

8)  Loosen nuts (49A) 

with a 24mm socket 

wrench.

9)  With a rubber mallet tap 

the back of the valve 

casing (50) and pull the 

valve casing off the stud 

bolt (49).

10) Remove  cover  plate 

(30)  with  a  10mm 

socket wrench.

Valve Seat identification markings

TO CHECK SEALS

13) Pull seal sleeves (38) 

and plungers (36) out 

of their fittings in the 

crankcase (1) using 

ring groove as a guide.  

Remove plunger from 

seal sleeve.

12)   Remove  tension 

spring  (40)  from  seal 

retainer (38).

CAUTION: 

 Don’t loosen the three plungers (36) before the valve casing has been 

removed otherwise the plunger (36) could hit against the spacer pipe (51F) 

when the pump is being turned.