10
DISPLACEMENT PUMP SERVICE
Disassembly
When disassembling the pump, lay out all removed parts
in sequence, to ease reassembly. Refer to Fig 6.
NOTE:
Repair Kit 222–784 is available to replace the
piston and intake valve seals. For the best re-
sults, use all the new parts in the kit. Parts in-
cluded are denoted with one asterisk, for exam-
ple (8*).
Repair Kit 222–785 is available to replace the
throat packings. For the best results, use all the
new parts in the kit. Parts included are denoted
with two asterisks, for example (3**).
1. Remove the displacement pump from the air motor
as explained on page 9.
2. Place the displacement pump in a vise, with the jaws
on the outlet housing (9).
3. Hold the flats of the priming piston rod (21) with an 8
mm wrench. Using a 3/4 in. wrench, unscrew the
priming piston nut (22) from the rod. Slide the priming
piston (23) and priming piston guide (24) off the rod.
Inspect the outer surface of the guide (24) and the in-
ner and outer surfaces of the piston (23) for scoring,
wear, or other damage.
4. Loosen the packing nut (2) using the packing nut
wrench (113) supplied, or a hammer and brass rod.
5. Remove the intake cylinder (20), using a 24 in. ad-
justable wrench. Remove the seal (19) and seat (18)
from the intake valve housing (16); always replace
the seal with a new one.
6. Unscrew the intake valve housing (16) from the cylin-
der (11), using a 24 in. adjustable wrench. Pull the
housing off the pump. The intake check valve as-
sembly (U) should slide down the priming piston rod
(21) as you remove the housing; if it does not slide
easily, loosen it by firmly tapping the top of the hous-
ing (16) with a rubber mallet.Take care not to drop the
assembly (U) as it comes free. Set the check valve
assembly aside for disassembly later.
7. Inspect the rod guide (17) while in place in the hous-
ing (16). Remove the rod guide
only
if it is visibly
damaged. Using a hammer and brass rod, gently tap
around the
outer edge
of the guide to loosen it.
8. Push the displacement rod (1) down as far as possi-
ble, then pull it and the priming piston rod (21) out of
the outlet housing (9) and cylinder (11).
9. Remove the packing nut (2), throat packings (3, 5)
and glands (4, 6) from the outlet housing (9).
DO
NOT
remove the fluid outlet nipple (7) and o–ring (8)
from the outlet housing unless they need replace-
ment.
10. Unscrew the bleeder valve (33) completely from the
outlet housing (9). Clean the bleed hole in the valve
body (33), and the valve port in the outlet housing (9).
11. Use a 24 in. adjustable wrench on the flats of the
pump cylinder (11) and unscrew the cylinder from the
outlet housing (9). Remove the o–rings (10). Inspect
the inside surface of the cylinder for wear, scoring or
other damage by holding it up to the light at an angle
or running a finger over the surface.
12. Inspect the surface of the displacement rod (1) and
priming piston rod (21) for wear , scoring or other
damage by running a finger over the surface.
13. Use a vise with soft jaws to hold the displacement rod
(1) by its flats. Place a 15 mm wrench on the flats of
the piston and unscrew the piston (13) and priming
piston rod (21) from the displacement rod (1). Re-
move the piston guide assembly (12, 14, 15) from the
piston (13), and set aside for disassembly later.
14. It is not necessary to remove the priming piston rod
(21) from the piston (13) unless your inspection re-
veals scoring, wear, or other damage to either part.
To disassemble, place the piston flats in a vise. Using
an 8 mm wrench on the rod flats, unscrew the rod.
15. Place the flats of the piston seat (15) in a vise. Using
an 8 mm (5/16 in.) dia. brass rod, unscrew the piston
guide (12) from the piston seat (15). See Fig 4. Re-
move the piston seal (14); always replace with a new
one. Inspect the mating surfaces of the piston (13)
and piston seat (15) for nicks, scoring or wear.
16. To disassemble the intake check valve assembly (U),
place the nut (27) in a vise and unscrew the intake
valve body (25) from the nut, using a 25 mm wrench.
See Fig 5. Remove the seal (41) from the nut (27)
and the other seal (26) from the valve body; always
replace them with new ones. Inspect the mating sur-
faces of the intake valve body (25) and seat (18) for
wear, scoring, or other damage.
NOTE:
The seal (41) is press–fit in the nut (27), and may
require cutting with a razor to ease removal.
17. Inspect all parts for damage. Clean all parts and
threads with a compatible solvent. Reassemble as
explained on page 12.
Fi 4
Fi 5
12
15
BRASS ROD
25
27
0205
0206
Summary of Contents for Metric CHECK-MATE 200
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