2001/01/22 Caterpillar

Off-Highway Truck/Tractor:

769D (S/N: 5SS1-UP; 5TR1-UP)

773D (S/N: 7CS1-UP; 7ER1-UP)

776D (S/N: 5ER1-UP; AFS1-UP)

777D (S/N: 2YW1-UP; 3PR1-UP; AGC1-UP)

777D HAA (S/N: AGY1-UP)

784B (S/N: 5RK1-UP)

784C (S/N: 2PZ1-UP)

785 (S/N: 8GB1-UP)

785B (S/N: 6HK1-UP)

785C (S/N: 1HW1-UP; APX1-UP)

785C HAA (S/N: 5AZ1-UP)

789 (S/N: 9ZC1-UP)

789B (S/N: 7EK1-UP)

789C (S/N: 2BW1-UP)

793 (S/N: 3SJ1-UP)

793B (S/N: 1HL1-UP)

793C (S/N: 4AR1-UP; 4GZ1-UP; ATY1-UP)

Quarry Truck:

771D (S/N: 6JR1-UP; 6YS1-UP)

775D (S/N: 6KR1-UP; 8AS1-UP)

Service Magazine SEPD0419, 1 June 1998, "Improved Brake Relay Valve Available For Certain Off-Highway Trucks". The information in this article is incomplete. Replace the article with the following information.

Description of Change: An improved 159-5149 Relay Valve Gp is available as a direct replacement for the following former relay valve groups: 8X-5444 Relay Valve Gp, 113-7866 Relay Valve Gp and 142-2516 Relay Valve Gp. The improved 159-5149 Relay Valve Gp has a larger radius at the exhaust port in order to prevent cracking from fatigue.

An improved 142-3439 Seal and Valve Kit is available in order to update the former relay valve groups to the improved 159-5149 Relay Valve Gp configuration. The 142-3439 Seal and Valve Kit may also be used for regular service maintenance of 159-5149 Relay Valve Gp .

Adaptable To: See Table 1 for the effective PINS of the improved 159-5149 Relay Valve Gp. The improved 159-5149 Relay Valve Gp is adaptable to all earlier trucks.

Table 1

Effectivity of 159-5149 Relay Valve Gp
Sales Model	Effective PIN
769D	(S/N: 5SS320)
771D	(S/N: 6YS211)
773D	(S/N: 7CS373)
775D	(S/N: 8AS275)
776D	(S/N: AFS76)
777D	(S/N: AGC77)
784C	(S/N: 5RK26)
785C	(S/N: 6HK897)
789C	(S/N: 2BW90)
793C	(S/N: 4AR364)