2009/06/29 Correction to Specifications , "Service and Parking Brake" {4251, 4267} Caterpillar

Underground Articulated Truck:

AD55 (S/N: ANW1-UP; DNW1-UP)

AD55B (S/N: JNW1-UP)

Specifications, RENR4720, "AD55 Underground Articulated Truck Braking System", "Service and Parking Brake". This module is part of Service Manual, RENR4720 Volume II.Specifications, RENR4720, "AD55 Underground Articulated Truck Braking System", "Service and Parking Brake". This module is part of Service Manual, RENR4778 Volume II.Specifications, KENR6084, "AD55B Underground Articulated Truck Braking System", "Service and Parking Brake". This module is part of Service Manual, KENR6715 Volume II.

The information in the above modules has changed. Replace the information with the following information.

Service and Parking Brake

Illustration 1	g00879812

(1) Thickness of 13 new friction discs, 13 new plates and one new damper assembly ... 104.27 ± 2.76 mm (4.105 ± 0.109 inch)

(2) 8X-4437 Plate

Thickness of one new plate ... 2.413 ± 0.064 mm (0.0950 ± 0.0025 inch)

Minimum permissible wear thickness ... 2.29 mm (0.090 inch)

(3) 8E-2183 Friction Disc

Thickness of one new friction disc ... 5.08 ± 0.13 mm (0.200 ± 0.005 inch)

Minimum permissible wear thickness ... 4.57 mm (0.180 inch)

Note: Lubricate the friction discs at assembly with SAE 30 Transmission Drive Train Oil (TDTO) or (T-04).

(4) 8X-4435 Damper

Thickness of one new damper ... 6.86 ± 0.24 mm (0.270 ± 0.010 inch)

Note: Install the damper with the facing material away from the plates and discs.

(5) 131-5935 Spring

Quantity ... 8

Free length ... 79.0 mm (3.11 inch)

Outside diameter ... 24.0 mm (0.94 inch)

(6) Rubber toric seals and all surfaces that contact the toric seals must be clean and dry when the parts are assembled. Apply a thin coat of oil on the contact surfaces of the metal seals prior to installing the metal seals. The metal seals must be assembled square with the bore. The rubber toric seals must not bulge and the rubber toric seals must not be twisted.

(7) 9D-6135 Spring (inner)

Quantity ... 18

Length under test force ... 90.50 mm (3.563 inch)

Test force ... 1535 ± 44 N (345 ± 10 lb)

Free length after test ... 115.49 mm (4.547 inch)

Outside diameter ... 26.59 mm (1.047 inch)

(8) 9D-6093 Spring (outer)

Quantity ... 20

Length under test force ... 90.50 mm (3.563 inch)

Test force ... 4235 ± 254 N (952 ± 57 lb)

Free length after test ... 116.50 mm (4.586 inch)

Outside diameter ... 46.02 mm (1.812 inch)

(9) Torque for the 23 bolts ... 530 ± 70 N·m (390 ± 52 lb ft)

(10) Torque for the five studs ... 110 ± 20 N·m (80 ± 15 lb ft)

(11) Torque for the five nuts ... 270 ± 40 N·m (200 ± 30 lb ft)

Note: Torque each nut (11) one revolution at a time in order to evenly pull down the housing. When all of the nuts bottom out, tighten the nuts to the specified torque in a criss cross pattern.