GENERAL HYDRAULIC SYSTEM REPAIR METHODS - Continued
INSTALLATION PACKINGS (O-RINGS)
Before installing a new packing, inspect the threads and packing seat (cavity) for nicks, cracks, and distortion.
Replace any damaged components.
Ensure the packing is the correct type and size.
Before installation, lubricate the new packing with engine lubricating oil.
While installing the packing, always protect it from cuts or nicks. Do not install packing directly over threads
(Figure 6). If available, install packing over the plastic or rubber thread guard that is supplied with new fittings.
If no thread guard is available, protect the packing by wrapping the fitting threads with heavy, smooth, lint-free
paper. See the illustrations below.
If a backup washer is used with the packing, it must be free of cuts, nicks, or distortion. An unserviceable
backup washer can cause the packing to distort or rupture when hydraulic pressure is applied and result in a
serious oil leak.
After the packing is installed, inspect it for damage and replace it again if necessary. Also, ensure it is not
twisted or distorted.