How to: Fit a Composite Piston Seal

Watch our video which demonstrates how to fit a composite piston seal.

1. You will need

1 x O-Ring Energiser

1 x double-acting piston seal

1 x bearing ring

1 x O-Ring

1 x Pick Set (with the points removed)

Silicone Lubricant

1 x Fitting Sleeve with taper on one side

1 x soft hammer with nylon heads

1 x Peg Spanner

2. Slide the O-Ring Energiser on to the rod

3. Prepare the composite piston seal

Gently manipulate it in your hands to make it easy to fit.

Slide the seal onto the rod.

4. Fit the O-Ring

Insert the smaller O-Ring into the groove of the front face of the piston.

5. Thread the piston on to the rod

Tighten with the peg spanner.

6. Fit the O-Ring Energiser

Fit into the groove of the piston using a straight seal pick.

Ensure any twists are removed.

7. Fit the composite piston seal

Place the composite piston seal into the groove on top of the O-Ring.

Take care when guiding the seal into place. In doing this the seal will clip into the groove.

You will now need to shrink the seal back to its correct size.

8. Shrink the composite piston seal back to size

Fit the bearing ring.

Using silicone grease, lubricate the tapered edge inside the Fitting Sleeve.

Push the sleeve onto the piston until the tapered edge covers the composite piston seal.

Gently tap on either side of the sleeve with a soft hammer, realigning the seal to its correct size.

Then, using the same technique on the opposite side, knock the sleeve back until it is removed.

The seal will now be at its correct size.


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