Changing seals

Repair

Changing seals

Changing seals

Note

If the percussion unit is dismantled, the complete set of seals must be replaced!

To dismantle the hydraulic breaker observe all instructions given in Chapter Dismantling.

To assemble the hydraulic breaker observe all instructions given in Chapter Assembling.

Changing cylinder seals

Note

Before fitting, check percussion piston and cylinder bore for possible scoring. In the majority of cases such scoring can be smoothed off using grain 600 emery cloth.

Once piston and cylinder bore have been washed clean and lightly coated with hydraulic oil, the new sealing elements can be fitted.

Use only new and genuine spare parts.

  1. 1.
    Replace the following seals in the lower sealing area of the cylinder:

    - Wiper (305)

    - Seals (385)

  2. 2.
    Coat sealing points lightly with hydraulic oil.

    The order of fitting is as follows:

  3. 3.
    Carefully press the seals (385) out of shape as shown in following diagram.

    The following diagram indicates how the sealing elements should be pressed out of shape for fitting in the appropriate inner grooves.

  4. 4.
    Fit seals (385) in the appropriate grooves. Ensure they are fitted the right way round.
  5. 5.
    Fit the wiper (305) in the appropriate groove.
  6. 6.
    After snapping into the groove, check the fit of the seals visually and using your fingers.
  7. 7.
    Roll a clean round wooden or plastic rod around the circumference to press the seals back into shape and ensure a correct fit.

Changing seals between cylinder and cylinder cover

  1. 1.
    Replace all o-rings and seals between cylinder and cylinder cover.
  2. 2.
    Grease new o-ring (120) with Parker O-Lube and refit into the appropriate groove in the cylinder cover.
  3. 3.
    Coat sealing grooves for seals (122 and 123) and o-rings (124) lightly with hydraulic oil.

    The order of fitting is as follows:

  4. 4.
    Carefully press the seal (122) out of shape as shown in the diagram before.
  5. 5.
    Fit seal (122) into the appropriate groove in the cylinder cover.
  6. 6.
    Fit the o-rings (124) in the appropriate grooves.
  7. 7.
    Carefully press the seals (123) out of shape as shown in the diagram before.
  8. 8.
    Fit seals (123) in the appropriate grooves. Ensure they are fitted the right way round.

Changing seal on the filling valve

WARNING

Component coming loose abruptly

The piston accumulator is under pressure, even when the hydraulic system has been depressurised. The filling valve might come loose unexpectedly and cause injuries.

  1. Never unscrew the filling valve »G« from the pressurised piston accumulator.

NOTICE

Damage to the filling valve

Nails, screwdrivers or similar objects can damage the filling valve.

  1. Never use nails, a screwdriver or similar objects to release nitrogen gas from the piston accumulator.

  1. 1.
    Make sure the hydraulic system is depressurised.
  2. 2.
    Grease new o-ring (183) with Parker O-Lube and refit.

Changing seal on the main control valve cover

  1. 1.
    Grease new o-ring (303) with Parker O-Lube and refit.

Change seals on port P and T

  1. 1.
    Grease new o-rings (397) with Parker O-Lube and replace on port »P« and »T«.