Note:
Always take time to lubricate all metal and nonmetal parts with a light film of oil
before reassembly. This step will ensure proper fit, at the same time protecting the pump's
nonmetal parts (i.e., the elastomers) from cutting and scoring.
To Check Valves
1. Screw-out inner hexagon screws (48A) with an allen wrench. Remove discharge plugs (48) with a
screw driver. Check o-rings (48B) on discharge plugs and replace as necessary.
2. Pull out pressure ring (48C). Remove the spring tension cap (47F) from the discharge valve plate
(47D) lying underneath by screwing in the 10mm screw. Take out the valve spring (47E) and
valve plate (47D). Pull out the discharge valve seat (47C) by means of slide hammer. Check
sealing areas of the valve plate and the valve seat for damage and replace worn parts. Check o-
rings (47A and 47B) and replace as necessary.
3. Screw spacer pipe (46G) out of the spring tension cap (46F) located in the suction valve lying
underneath. Remove the suction valve assembly (46) by screwing in a 10mm screw. Check o-
rings (46A and 46B) and replace as necessary. If the inlet valve seat (46C) remains in the valve
casing (43), remove it with a slide hammer. Check the sealing areas of the inlet valve plate (46D)
and the inlet valve seat (46C) for damage and replace worn parts.
4. After reassembling the above items, tighten the inner hexagon screws (48A) to 35 ft.-lbs.
To Check Seals and Plunger Pipes
1. Loosen the eight inner hexagon screws (49) and pull of the valve casing (43) to the front. Pull seal
sleeves (35) out of the guides in the crankcase and over the plunger pipes (29B). Remove sleeve
support ring (41), sleeves (40) and grooved rings ( GP5136-5100 only) (36). Replace worn parts
as necessary.
2. If a plunger pipe (29B) is worn out, loosen the tension screw (29C) and pull off the plunger pipe to
the front. Clean the contact surfaces of the crosshead assembly (25) thoroughly. Place the new
plunger pipe carefully through oiled seals back into the seal case. Check o-rings (35A and 35B as
well as 37B in GP5136-5100 only) on the seal sleeves (35) and replace as necessary.
3. Push the Seal Sleeves (35) together with the plunger pipe (29B) back into the crankcase guide.
Turn the crankshaft (22) carefully until the crosshead assembly (25) comes up against the plunger
pipe. Put a new steel ring (29D) onto the tension screw (29C). Cover the thread of the tension
screw and the oil scraper and apply a liquid adhesive such as lock-tite. Tighten tension screw to 26
ft.-lbs..
Important!!
Do not get any adhesive between the plunger pipe (29B) and the centering sleeve (29A).
The plunger pipe should not be strained by excessive force on the tension screw (29C) or
through damage to the front surface of the plunger. If these conditions are ignored, the
plunger pipe will probably break.
4. Tighten the inner hexagon screws (49) to the valve casing (43) to 85 ft.-lbs.
9
Repair Instructions - GP5136-5100 and GP5145-5100 Pumps
