Hypertherm HyPrecision 100D, Instruction Manual

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Piston Seal and Wear Ring Replacement
The piston uses a long life, capped t-seal and wear rings for the longest possible life. After extended use,
the intensifier may not stroke efficiently and the pump will generate heat. This is a sign that the piston
seal is bypassing oil and needs to be replaced. Special tools are required to load the new seal on the
piston and load the new piston/seal assembly into the hydraulic cylinder. Contact an authorized
Hypertherm service representative for further information regarding this procedure.
Plunger Bearing
The plunger bearing may become worn and may lose its precision fit relative to the plunger. The bearing
should be replaced if the plunger fit is too loose. A bearing ID measurement of
0.0015 in . greater than
the plunger diameter is considered too loose. The bearing can be changed when the hydraulic end cap is
off the hydraulic cylinder. Repeated premature seal failure can be attributed to a worn out bearing. The
bearing should also be replaced any time a high-pressure cylinder is replaced.
Reassembling the Center Section
1. Verify that all surfaces are clean and free of contamination.
2. Replace the O-ring and backup on the end cap. Place the O-ring on the side of the groove towards
the piston and the backup on the side away from the piston. The concave side of the backup is
towards the O-ring. Lubricate the O-ring with hydraulic oil.
3. Install the plunger bearings in the end caps.
4. On a flat clean surface, slide the hydraulic end caps into each end of the hydraulic cylinder.
5. Thread the four 7/8 in. cap screws in and lightly pull the end caps against the hydraulic cylinder
until they bottom-out. The cap screw threads should be greased with multi-purpose lithium
grease such as Lubriplate No. 1552.
6. Secure the center section and manifold mounting face to a flat surface before applying torque to
the 7/8 in. cap screws. Bolt it to the manifold first and then to the frame on the pump before
applying torque.
7. Torque the 7/8 in. cap screws to 100 ft-lb . Then increase torque in 50 ft-lb increments using a
cross pattern to 275 ft-lb .
The eight bolts that connect the manifold to the hydraulic end caps must be
torqued to the appropriate value as given in the Torque Specifications section of
this manual.
8. Reassemble the end of the intensifier as described above in Installing New HP Seals .
9. When reconnecting the HP tubing loosen the four bolts that secure the intensifier to the frame.
This will allow it to float into the correct location. Tighten the four frame connect bolts.
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