SEAL RETAINER HD712-01049 / HD71201049 — Furukawa Compatible

What the SEAL RETAINER does

Sealing elements are the highest-turnover components in a hydraulic drifter. A percussion mechanism cycles thousands of times a minute, so a seal on a moving surface sees more load reversals in one shift than most hydraulic seals see in a year. Static seals hold pressure between housings and covers; dynamic seals ride against a moving piston or shank and carry the whole burden of keeping oil in and drill cuttings, flushing water and rock dust out.

Signs it needs replacing

• Oil weeping or spraying from the joint the seal sits behind
• Falling percussion pressure, or a drifter that will not hold pressure at rest
• Water or flushing air appearing in the return oil, or oil in the flushing line
• Emulsified, milky oil in the tank — a sign water is crossing a barrier seal

Before you fit it

Seals are replaced as a set, not one at a time: the surrounding seals have run the same hours and will fail shortly after. Inspect the sealing surface before fitting — a scored piston or bushing will destroy a new seal in hours, and that is the usual reason a fresh seal leaks again within a week.

General guidance for this class of component. Always work to the torque figures, clearances and service intervals in your machine's own manual.

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