O-Ring Seals; Sealants Used; Spring Pins - New Holland T4.90 FB Service Manual

1.3.5 O-ring seals

Lubricate O-rings before fitting in their respective seats to prevent them from twisting and seating
incorrectly, compromising the integrity of the seal itself.

1.3.6 Sealants used

A number of different sealants must be used during assembly, with specific characteristics to suit different
applications.
Sealants
LOCTITE 518 mastic sealant must be used where a hermetic seal is required between two or more
components.
Usage:
- Remove any encrusted residue from both mating surfaces with a wire brush.
- Degrease the surfaces thoroughly with one of the following cleaners: trichloroethylene, petroleum
spirit, acetone or a solution of hot water and caustic soda.
- Spread the product evenly onto just one of the contact surfaces and assemble.
Thread lock compound
LOCTITE 243 and LOCTITE 270 thread lock compounds are used when it is necessary to impede a screw
or nut from loosening.
Usage:
- Clean as described previously.
- Spread one or two drops of the product onto the thread of the screw or in the threaded hole.
- Fit the screw or nut and tighten.

1.3.7 Spring pins

When fitting split spring pins, ensure that the split in the pin itself is facing in the same direction as the
force exerted on the pin.
Coiled spring pins can be fitted in any orientation.
INTRODUCTION
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