Page 12
12/18/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
ppstack1
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:4
SHEET 2 OF 2
_
PISTON PUMP STACK PACK REPLACE
.X = .060 MIN. MACHINE SURFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT
±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
12/18/08
DKY
DATE
DATE
4010 320TH ST. PO BOX 189
BOYDEN, IOWA 51234
THE DRAWING AND ALL
INFORMATION THERE
ON ARE THE PROPERTY OF
DEMCO
TOLERANCES
ppstack1
DRAWN BY
ENG APPOV.
DESCRIPTION
DRAWING. NO.
REV
SCALE: 1:4
SHEET 1 OF 2
_
PISTON PUMP STACK PACK REPLACE
.X = .060 MIN. MACHINE SUFACE 250
.XX = ±.030 BREAK ALL SHARP EDGES
.XXX = ±.010 BEND AND DRAFT
±1°
UNLESS OTHERWISE
SPECIFIEDALL DIMENSIONS
ARE IN INCHES
THIRD ANGLE
PROJECTION
STACKPACK REPLACEMENT
1. Remove large cylinder clamp (A), end cap (B), large
o-ring (C) and small o-ring (D). After this has been done
remove stainless steel piston nut (E) and thrust washer (F).
3. Pull and twist off stackpack retainer assembly (H).
A
A
b
E
F
D C
AA
A
A
C
D
G
2. Remove large clamp (A). Proceed by pulling the Piston,Large
O-ring (C), Small O-ring (D), and the cylinder hous-
ing assembly (AA) off of the piston rod (G)
at the same
time.
If this is not done simultaneously the cylinder
housing assembly will have to be disassembled to properly
install wipers & support ring over the piston. Refer to the
Piston Wiper Replacement
section on pages 12 & 13.
4. Oil stackpack and O-ring. Insert stackpack retainer assembly
into pump by sliding it over the piston rod.
5. Place large o-ring over the flare on drive case, then slightly
stretch small o-ring. This will help hold it in the lip of the rear
cylinder housing. Place the first thrust washer on piston
rod, then slide the cylinder housings into position with the
piston still lodged in the piston wipers. Roll the large o-ring
over the flare and into the groove. Secure with large cylinder
clamp (A). Insert and tighten the thrust washer and 3/8”
stainless steel nylon insert locknut.
6. Place large o-ring over the flare on the front cylinder hous-
ing then slightly stretch small o-ring. This will help hold it in
the lip of the cylinder housing. Replace end cap and roll
the large o-ring over the flare and into the groove. Secure
with large cylinder clamp (A).
H
