Kärcher HDS 9/50 De Tr1 Service Manual page 121

 Press in the new suction valves (lubricate the O-rings
with silicon grease).
NOTE
Ensure the correct alignment of the valve crosspieces.
 Insert the lockscrews of the suction valves and tighten
them to 40 Nm (grease O-rings).
English 5.906-736.0 Rev. 00 (07/15)
121