Usage:
Remove Jacobs Engine Brake
1. Loosen clamp (1) and disconnect breather tube (2) from the hose.
2. Remove four bolts (5) that hold the elbow to the inlet manifold. Remove elbow (3) and air pipe (4) as a unit.
3. Remove bolts (7) that hold the valve covers in place. Remove valve covers (6).
4. Disconnect solenoid lead wires (8) and (10) from the terminal in the Jacobs spacer.
5. Remove eight Jacobs nuts (9) and four Jacobs bolts that hold the Jacobs spacers to the valve cover bases. Remove Jacobs spacers (11).
NOTE: Do Steps 6 through 13 for each end of the engine. The front half of the engine is shown.
6. Remove four Jacobs studs (12) and Jacobs washers. Remove three bolts (13) and remove valve cover base (4).
7. Remove Jacobs nuts (15), Jacobs washers, Jacobs bolts (16) and the Jacobs washers that hold the Jacobs brake housing assembly in place.
8. Remove Jacobs brake housing assembly (17).
9. Remove Jacobs head bolts (19) and remove Jacobs support brackets (18) from the cylinder head.
10. Remove inner fuel lines (20).
11. Remove Jacobs washers (21) and Jacobs shims (22) from the Jacobs stud assemblies.
12. Remove bolt (24) and two Jacobs stud assemblies (23) that hold the rocker shaft assembly to the head. Remove rocker shaft assembly (25).
13. Remove Jacobs exhaust valve bridges (27) from the exhaust valves only. The intake valves have the Caterpillar intake valve bridges. Remove the Caterpillar intake valve bridges (26).
14. Remove Jacobs engine control switch (29) from the governor housing. Remove Jacobs actuator arm (28).
Install Jacobs Engine Brake
NOTE: Do each step for each end of the engine. The front half is shown.
1. Put clean engine oil on the bridges and dowels.
2. Install Jacobs exhaust valve bridges (1) and the Caterpillar intake valve bridges (2) on the dowels.
3. Keep pressure by hand on the bridges and turn the adjustment screw clockwise until contact is made with the valve stem. Turn the screw an extra 20° to 30°. This will make dowel straight in guide and make compensation for gap (slack) in the threads. Hold adjustment screw in this position and tighten locknut to a torque of 22 ± 3 lb.ft. (28 ± 4 N·m).
4. Put rocker shaft assembly (3) in position on the cylinder head.
5. Install Jacobs washers (4) on the Jacobs stud assemblies (6). Put clean oil on the threads and install washer and bolt (5) and Jacobs stud assemblies (6). Tighten the center bolt and Jacobs stud assemblies in steps of 50 lb.ft. (70 N·m) each until a final torque of 330 lb.ft. (450 N·m).
6. Make an adjustment to the valves to have a clearance of .015 (0.38 mm) for the intake valves and .030 (0.76 mm) for the exhaust. Tighten the locknuts to a torque of 22 ± 3 lb.ft. (28 ± 4 N·m) and check the valve clearance again. See TESTING AND ADJUSTING for correct procedure.
7. Install a new Jacobs O-ring seal (7) on the Jacobs oil supply adapter in the rocker shaft assembly. Put clean oil on the Jacobs O-ring seal.
| NOTICE |
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Do not cause damage to the O-ring seals on the inner fuel lines. |
8. Install inner fuel lines (8). Tighten the fuel line nuts to a torque of 30 ± 5 lb.ft. (40 ± 7 N·m) with tooling (A) and (B).
9. Put Jacobs support brackets (9) in position as shown. Put oil on the threads of the Jacobs bolts (10). Install the washers on the Jacobs bolts. Install Jacobs bolts (10) that hold the Jacobs support bracket in place. Tighten the Jacobs bolts to a torque of 330 lb.ft. (450 N·m).
10. Install Jacobs washers (11) on the Jacobs stud assemblies.
| NOTICE |
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Be extra careful not to cause damage to the Jacobs oil supply adapter O-ring seal when the Jacobs brake housing assembly is installed. |
NOTE: The brake housing assembly with the mark "FRONT" on it must be installed on the front three cylinders. The brake housing assembly with the mark "REAR" must be installed on the rear three cylinders.
11. Put Jacobs brake housing assembly (12) in position on the engine.
| NOTICE |
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Do not install the Jacobs nuts that hold the Jacobs brake housing assembly on the Jacobs stud assemblies. |
11. Install the Jacobs washers and Jacobs bolts (13) that hold the Jacobs brake housing assembly to the Jacobs support brackets. Tighten the Jacobs bolts to a torque of 10 lb.ft. (14 N·m).
12. Use feeler gauge (14) as shown and measure the gap between the Jacobs brake housing assembly and the Jacobs washer at each end of the Jacobs brake housing assembly.
13. Measure the thickness of Jacobs shim packs (15). Use a knife to make a separation of the shim packs. Measure the shim packs again. Do this until the shim packs are the same thickness as the gaps measured in Step 12.
14. Remove the Jacobs brake housing assembly and remove the Jacobs washers from the Jacobs stud assemblies.
15. Install correct Jacobs shim packs (15) on the Jacobs stud assemblies. Install Jacobs washers (11).
| NOTICE |
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Be sure Jacobs shim packs (15) are under Jacobs washers (11). |
| NOTICE |
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Be extra careful not to cause damage to the Jacobs oil supply adapter O-ring seal when the Jacobs brake housing assembly is installed. |
16. Put Jacobs brake housing assembly (12) in position on the engine.
17. Install Jacobs washers and Jacobs nuts (16). Install Jacobs washers and Jacobs bolts (13). Tighten Jacobs nuts (16) to a torque of 100 lb.ft. (135 N·m). Tighten Jacobs bolts (13) to a torque of 48 lb.ft. (64 N·m).
18. Use two feeler gauges (14) as shown and make an adjustment to the slave piston clearance (lash) at any cylinder location where the exhaust valves are closed. Turn adjustment screw (17) for the correct clearance (lash). For the correct clearance see the Subject, JAKE BRAKE ADJUSTMENT in Testing and Adjusting.
19. Tighten locknuts (18) after the clearance (lash) has been made.
20. Put valve cover base (19) in position on the cylinder head.
21. Check to make sure there is no contact between the No. 3 and No. 6 exhaust valve bridges and the valve cover bases at area (X) as shown.
NOTE: It will be necessary to remove material from the valve cover bases if there is contact between them.
22. Install Jacobs washers (21) on the Jacobs studs. Install Jacobs studs (20) in the four locations shown with the short threaded end toward the cylinder head. Install bolts (22). Tighten the Jacobs studs (20) and bolts (22) to a torque of 120 ± 24 lb.in. (13.6 ± 2.8 N·m).
23. Put Jacobs spacer (23) in position on top of the valve cover bases.
24. Install Jacobs nuts (24) on the Jacobs studs. Install Jacobs bolts (25) that hold the Jacobs spacer in place.
25. Connect solenoid lead wire (26) to the terminal in the Jacobs spacer.
NOTE: If the engine is in the vehicle, start the engine, let it run at idle speed and remove (bleed) the air from the Jacobs brake housing assemblies. To remove (bleed) the Jacobs brake housing assemblies for operation immediately, push (depress) the solenoid armature five or six times in sequence with the engine in operation to permit oil to fill the passages in the housing assemblies.
26. Put valve cover (27) in place on the Jacobs spacer. Check to make sure that there is no contact between the valve cover and the Jacobs brake housing assemblies. Install the bolts that hold the valve cover in place. Tighten the bolts to a torque of 120 ± 24 lb.in. (13.6 ± 2.8 N·m).
27. Slide breather tube (29) in the hose and tighten clamp (28).
28. Put clean oil on the O-ring seal on air pipe (31). Install air pipe (31) and elbow (30) as a unit. Make sure the gasket is in place between elbow (30) and the inlet manifold. Install four bolts (32).
29. Install Jacobs engine control switch (34) on the governor. Install Jacobs actuator arm (33) as shown with the Jacobs button head screws. Make an adjustment to the Jacobs actuator arm so when the engine is at low idle speed the Jacobs engine control switch (34) is in the "ON" position.