摘要 |
<p>A filled piston (10) has a tube (19) extending axially through the core (13) of filler material. The tube (19) provides the passage (23) through which hydraulic fluid passes to lubricate the bearing surfaces of components associated with the piston (10). This eliminates the problem of the hydraulic fluid eroding the filler material and thus the need for visual inspection of the passage through the piston.</p> |