GASKET-COVER 1Y7578 - Caterpillar

Engine: 3508 (S/N: 8TL1-UP) 3508B (S/N: CBB1-UP; S2B1-UP; S2D1-UP; S2E1-UP; S2F1-UP; BAG1-UP; 2BM1-UP; 7SM1-UP; 1TW1-UP; 2HW1-UP; 3DW1-UP; BPX1-UP; 1FZ1-UP; CNB1-UP; 6PN1-UP; S2A1-UP; LPD1-UP; 3DM1-UP; 5PS1-UP; CTC1-UP) 3512B (S/N: S2J1-UP; S2K1-UP; S2L1-UP; S2M1-UP; 7HM1-UP; 8EM1-UP; BRN1-UP; 4TN1-UP; 1PW1-UP; 2GW1-UP; 4AW1-UP; 5AW1-UP; 2EZ1-UP; CTB1-UP; CTH1-UP; BRC1-UP; 2AF1-UP; 4DR1-UP; 3ZW1-UP; NSC1-UP; FFG1-UP) 3516B (S/N: CBN1-UP; 8CN1-UP; 8KN1-UP; 9AN1-UP; S2R1-UP; 2FW1-UP; 3CW1-UP; 4BW1-UP; S2X1-UP; CTA1-UP; 1NW1-UP; LEK1-UP; CTJ1-UP)Pumper: SPF343 (S/N: 6RZ1-UP) SPT343 (S/N: 5XZ1-UP)Introduction
Do not perform any procedure in this Special Instruction until you read this information and you understand this information. The limit switches are being relocated to a position that will improve the service life of the limit switches and of the air shutoff valve.Also, A vibration damper has been added to the air shutoff valve. The vibration damper is installed in the original location of the limit switch.Note: New limit switches must be used in this conversion. The new switches have normally closed contacts. The old switches have normally open contacts.
Illustration 1 g01201688
Former location of the limit switch
Illustration 2 g01304161
New location of the limit switch and of the vibration damper (1) 263-2905 Limit Switch As (2) 289-8498 Air Shutoff Damper Gp System Operation
The new switches for the air shutoff valves are normally closed switches. The new switches are in the closed state when the gates for the air shutoff valves are latched in the OPEN position. If the air shutoff valve is in the CLOSED position, the new switches are in the open state. This will cause an emergency stop condition. The engine will also shut down. This also prevents the engine from starting.Conversion Procedure
Table 1
Required Parts (1)    
Quantity     Part Number     Description     Torque    
2     263-2905     Limit Switch As     16 3 N m (142 27 lb in)    
2     272-7102     Cap        
2     289-8498     Air Shutoff Damper Gp        
4     4P-8134     Clip        
4     0S-1588     Bolt    
47 9 N m (353 7 lb ft)    
8     9X-6772     Cable Strap        
( 1 ) Quantity that is required for one engine
Illustration 3 g01201758
(1) 227-7483 Limit Switch As
Disconnect both switches (1) from the engine wiring harness.
Remove switches (1) from both of the air shutoff valves.Switches (1) will not be reused.
Illustration 4 g01304165
(2) 289-8498 Air Shutoff Damper Gp
Illustration 5 g01304171
Install damper (2) into the threaded hole.
Table 2
Parts for the 289-8498 Damper    
Item     Part Number     Description    
3     288-2766     Housing    
4     288-2767     Spring    
5     288-2768     Plunger    
6     3J-1907     O-Ring Seal    
7     9S-8004     Plug    ReferenceRefer to Special Instruction, REHS3005 for the inspection and maintenance instructions for the damper.
Illustration 6 g01304174
(8) 215-2705 Cap
Remove cap (8) .The fasteners will be reused. Cap (8) will not be reused.
Illustration 7 g01304179
(9) 263-2905 Limit Switch