General Pump MH - Manual (Page 13)

GENERAL PUMP
A member of the Interpump Group
MH SERIES
Page 13
With the tool in place, rotate the crankshaft until the
packing support is pushed out together with plungers
and cylinders (Fig. 21). Repeat the operation for each
pumping unit.
Remove the wipers from the piston guides (1, Fig. 22
and Fig. 23).
Separate the pumping unit components and check them
for wear. Pressure packing replacement is carried out
by hand without need of special tools (Fig. 24)
A little bit of grease helps when sliding the packings into
the packing support. Pressure packings and o-rings
should always be replaced at every disassembling of
the pumping unit.
In order to fit the new scraper in place shape it manually
as shown in Fig. 25.
VERY IMPORTANT! The scraper is provided with an
internal lip which performs the correct scraping effect only
if oriented toward the fluid end. See window inside Fig. 25.
Put the pumping unit components together and fit them
back in the pump crankcase. Tighten the plunger screws
(1, Fig. 18) with a torque wrench set for 72.3 ft. lbs.
Grease the pressure packings through the greasers (2,
Fig. 23) by means of a hand pump. Stop greasing when
the pump trigger becomes hard to operate: that means the
grease chamber is full. Head back in place, head screws
tightened at 260.3 ft. lbs.