Sealey Hydraulic Jack Oil 500ml. This hydraulic oil is recommended for use in all Sealey jacks (trolley and bottle) and cranes, and is also suitable for other brands. It eliminates sponginess and slow system response. Suitable for systems requiring hydraulic fluid meeting ISO VG222.23. Fully inhibited with a low pour point for ease of use, even in the coldest weather. Note: Never use brake fluid to top-up a hydraulic unit.