450E Backhoe Loader Axles, Differential and Brakes Service Brake Control - Adjust Caterpillar

ReferenceRefer to Operation and Maintenance Manual, SEBU8699, "450E Backhoe Loader", "Braking System - Test" for the service brake test.

ReferenceRefer to Testing and Adjusting, UENR0267, "450E Backhoe Loader Axles, Differential, and Brakes", "Service Brakes - Test" for the service brake test.

Adjustment Procedure

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Illustration 1	g01302042
(A) 0.56 mm to 0.90 mm (0.022 inch to 0.035 inch) (B) Limit Switch (1) Stop Plate (2) Locknut (3) Set bolt (4) Right brake pedal (5) Left brake pedal (6) Lock plate

1. Unlock the lock plate (6) .

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Illustration 2	g01302136
(A) 0.56 mm to 0.90 mm (0.022 inch to 0.035 inch) (B) Limit Switch (2) Locknut (3) Set bolt (4) Right brake pedal (5) Left brake pedal (6) Lock plate (7) Rod end (8) Locknut (10) Pushrod (11) Boot (12) Master cylinder

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Illustration 3	g01302129
(C) Slot for the lock plate (6) Lock plate

Note: The brakes have identical controls. Adjust one brake control at a time.

2. Unseat the boots (11) from the master cylinder (12) .

3. Pull both pedals (4) and (5) upward. Adjust the set bolt (3) so that the Lock plate (6) aligns with the slot for the lock plate (C). Tighten locknut (2). Ensure that the limit switches (B) must be engaged when the pedals are against the stops.

4. Depress the brake pedal (4) and release the brake pedal. This process is called stroking. Fully stroke and release brake pedal (4) six times in order to obtain the nominal position of the master cylinder piston.

5. Loosen nut (8) .

6. Back off pushrod (10). Insert a 0.76 mm (0.030 inch) shim between the brake pedal (4) and the set bolt (3). Adjust pushrod (10) until contact is made between the pedal and the shim. Also, adjust pushrod (10) until initial resistance is felt from the master cylinder (12). Tighten nut (8) to a torque of 20 ± 5 N·m (177 ± 44 lb in). Pushrod (10) should not be allowed to move when nut (8) is tightened. Remove the shim.

7. Move pushrod (10) and rod end (7) in order to ensure that free play exists. Measure the gap (A) that is between the brake pedal and the set bolt (3) with a feeler gauge. The measurement on the gap (A) should read a minimum of 0.56 mm (0.022 inch).

   Note: Ensure that a 0.9 mm (0.04 inch) shim will not fit between the stop on the brake pedal and the plate assembly.

8. Adjust the brake pedal if the gap is not within allowed specifications.

9. Repeat the above procedure for the left brake pedal.

   Note: For the left pedal (5), you will use the lock plate (1) instead of the set bolt (3) .

10. Ensure that the Lock plate (6) aligns with the slot for the lock plate (C) .

11. Ensure that boot (11) is sealed properly against the master cylinder.