Usage:
776B (6JC) Tractor;
777B (4YC),
785 (8GB),
789 (9ZC) Off-Highway Trucks
Description of Change: The new 171-6696 Diaphragm and 170-7149 Cap are available through parts-service for the 4T-4178 Valve Group-Diverter. The 171-6696 Diaphragm and 170-7149 Cap will replace the former 4J-4282 Diaphragm and 4J-4281 Plate.
When the 171-6696 Diaphragm and 170-7149 Cap are used together, the new diaphragm will provide longer service life than the former diaphragm.
NOTE: The 171-6696 Diaphragm and 170-7149 Cap must be used together to achieve improved service life.
Illustration 1:
View of 4T-4178 Valve.
To replace the former plate and diaphragm, use the following steps:
1. Remove the four bolts (D), plate (B), and diaphragm (A).
2. Thoroughly clean chamber (C) of any oil, water, rust, or contamination.
Illustration 2:
View of area on piston to inspect.
3. Check contact area of piston (E) from point (G) clockwise to point (H) for damage, rust and contamination. The piston must have a smooth and clean surface where it contacts the diaphragm. Replace 9J-4940 Piston if necessary.
NOTE: An assembly instruction will be packaged with the 171-6696 Diaphragm.
4. Assemble 9J-4940 Piston, 171-6696 Diaphragm, 170-7149 Cap and four bolts (D). Tighten bolts to a torque of 25 ± 6 N·m (18.4 ± 4.4 lb ft).
Adaptable To: 776B (4JC1-77) Tractor, 777B (4YC1-1128), 785 (8GB1-385) and 789 (9ZC1-308) Off-Highway Trucks.