18
repairs at the unit
Impact 400
11.2
INleT AND ouTleT vAlve
1. Remove the screw that secures the pressure control knob.
Remove the knob.
Remove the five screws in the front cover and then
remove the front cover.
2. Switch the unit ON and then OFF so that the piston rod is
positioned in the lower stroke position.
Danger of crushing - do not reach with the fingers
or tool between the moving parts.
3. Unplug the power plug from the outlet.
4. Remove the retaining clip from the connecting bend at the
suction hose and pull off the suction hose.
5. Screw off the return hose.
6. Swivel the unit 90° to the rear in order to work more easily
on the material feed pump.
7. Unscrew the inlet valve housing (Fig. 10, Item 1) from the
pump manifold (2).
8. Remove the lower ball guide (6), lower seal (5), inlet valve
ball (4), inlet valve seat (3) and O-ring (8).
9. Clean all the parts with the corresponding cleaning agent.
Check the inlet valve housing (1), inlet valve seat (3)
and inlet valve ball (4) for wear and replace the parts if
necessary.
1
3
4
6
5
7
2
8
10. Unscrew outlet valve housing (Fig. 11, Item 9) from the
piston (10) with adjusting wrench.
11. Remove the upper ball guide (14), crush washer (13), outlet
valve ball (12), and outlet valve seat (11).
12. Clean all the parts with the corresponding cleaning agent.
Check outlet valve housing (9), outlet valve seat (11),
outlet valve ball (12) and upper ball guide (14) for wear
and replace parts if necessary.
13. Carry out installation in the reverse order. Make sure
the outlet valve retainer (9) is reinstalled with the non-
threaded “lip” facing up into the piston. Lubricate O-ring
(Fig. 10, Item 8) with machine grease and ensure proper
seating in the inlet valve housing (Fig. 10, Item 1).
14
10
9
11
12
13
11.3
pAckINgS
DISASSemBly (fIg. 12)
1. Remove inlet valve housing in accordance with the steps
in Chapter 11.2. It is not necessary to remove the outlet
valve.
2. Remove the yoke screw (14) and washer (15) that secures
the dowel pin (16). The dowel pin connects the yoke (17)
to the piston (18).
3. Using a pliers, pull the dowel pin (16) out.
4. Rotate the pump shaft so the piston is in the top dead
center position. Press the yoke (17) against the top bushing
(19) with a screwdriver, for example. This is required to
disassemble all the parts.
5. Remove the piston assembly (18) by pushing down on the
piston near the yoke (17).
6. Unscrew and remove the upper bushing (19) using an
adjustable wrench.
7. Remove the worn seals using a flat head screwdriver
or punch. Remove the upper packing (20) from the top
and the lower packing (21) from the bottom by pressing
against the side of the seal and popping it out. Be sure not
to scratch the housing where the seals are located.
8. Clean the area where the new packings are to be installed.
