Installation of Heavy Duty Brakes{3278, 4251} Caterpillar

Installation of Heavy Duty Brakes{3278, 4251}

Usage:

725 AFX

Articulated Truck:: 725 (S/N: AFX133-UP)

Introduction

Reference: Disassembly and Assembly, RENR3447, "725 and 730 Articullated Trucks Machine Systems".

Reference: Disassembly and Assembly, RENR3448, "725 and 730 Articullated Trucks Power Train".

This Special instruction outlines the parts and the location of the parts that are required to install a heavy duty brake group on the listed machines.

All of the components that are required for the 725 modification to the service brakes must be ordered from the Caterpillar parts system. Refer to table 1 for the full parts list.

Do not perform the procedures that are outlined in this Special Instruction until you understand the information that is contained in this document.

Required Parts

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Table 1
The following components are required.
Item	Qty	Part Number	Part Description
1	2	2U-6126	Plug
2	2	2U-9526	Boss
3	2	2V-7390	Shim Pack
4	2	3T-6541	Duo-Cone Seal Gp
5	2	4U-3719	Boss
6	4	5P-8867	Flared Insert
7	2	7U-9277	Manifold
8	2	7X-0732	Hard Washer
9	2	9X-3975	Seal
10	2	128-5242	Dust Cover
11	2	138-2318	Disc
12	1	148-2751	Tube As
13	1	148-2752	Tube As
14	1	148-2754	Tube As
15	1	148-2755	Tube As
16	1	148-5170	Bracket
17	2	6V-8639	Connector
18	1	148-8375	Elbow
19	1	148-8427	Tee As
20	1	148-9559	Guard
21	1	148-9560	Guard
22	1	150-3908	Bracket
23	2	159-7596	Brake Group
24	1	160-6937	Tube As
25	1	169-4273	Tee As
26	2	195-9464	Spacer
27	1	198-0968	Hose As
28	32	1D-4609	Bolt
29	2	5H-2767	O-Ring Seal
30	2	5P-4116	Hard Washer
31	52	5P-8247	Hard Washer
32	3	6V-9169	Bulkhead Nut
33	2	7M-8485	O-Ring Seal
34	1	7X-0575	Hard Washer
35	52	8S-9092	Bolt
36	3	8T-1885	Clip
37	3	8T-1886	Clip
38	6	8T-4121	Hard Washer
39	4	8T-4123	Washer
40	1	8T-4133	Nut
41	2	8T-4137	Bolt
42	2	8T-4183	Bolt
43	1	8T-4186	Bolt
44	2	8T-4191	Bolt
45	2	8T-4194	Bolt
46	2	8T-4197	Bolt
47	4	8T-4223	Hard Washer
48	2	8T-4224	Hard Washer
49	2	8T-7547	Bolt
50	2	9X-3969	Ring Seal
51	2	200-5937	Lubricant

Disassembly Procedure

Remove the rear tires and rims. Refer to Disassembly and Assembly, RENR3448, "Tire and Rim Remove".

Remove the axle shafts from the rear axle. Refer to Disassembly and Assembly, RENR3448, "Axle Shaft - Remove".

Remove the final drives for the rear axle. Refer to Disassembly and Assembly, RENR3448, "Final Drive- Remove".

Remove the rear spindles and wheels. Refer to Disassembly and Assembly, RENR3448, "Wheel Bearings and Duo-cone Seal - Remove".
Note: The disassembly procedure in step 4 describes a procedure with an installed brake group. Disregard all references to removing the brake group.

Assembly Procedure

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Illustration 1	g01060541

Inspect and clean the threaded holes in the wheel hub. Make sure that the threads are free of paint and also dry. Clean all paint from the mating faces of the wheel hub and the disc. Position disc (11) onto the wheel hub. Install 26 bolts (35) and 26 washers (31) in order to secure the disc to the wheel hub.

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Illustration 2	g01060867

Use the following procedure to tighten bolts (35) :
1. Tighten bolts 1 through 26 in a diametrical opposed sequence to a torque of 120 ± 20 N·m (88.5 ± 15 lb ft).
1. Loosen bolt 1.
1. Tighten bolt 1 to a torque of 120 ± 20 N·m (88.5 ± 15 lb ft). Finally turn the bolt through an extra turn of 120°.
1. Repeat step 2.b and step 2.c for bolts 2 through 26.

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Illustration 3	g01061718

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Illustration 4	g01061710

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Illustration 5	g01061711

Install the rear spindle and the wheel with the brake group (23) and dust guard (10). The service brake is mounted vertically on the axle toward the front of the machine. Use 16 new bolts (28), 14 washers, 8 spacers which were removed during the disassembly procedure and spacer (26) which is installed between the two bolts either side of the brake port. Refer to Disassembly and Assembly, RENR3448, "Wheel Bearings and Duo-cone Seal - Install" and Disassembly and Assembly, RENR3447, "Service Brake - Install" for the correct torque and settings.
Note: Do not use bolts (28) in order to position the wheel hub onto the axle housing without installing the spacers or washers as internal damage to the seal carrier may occur.

Repeat step 3 for the opposite side.

Install the final drives for the rear axle. Refer to Disassembly and Assembly, RENR3448, "Final Drive- Install".

Install the axle shafts into the rear axle. Refer to Disassembly and Assembly, RENR3448, "Axle Shaft - Install".

Apply the foot brake several times in order to relieve the pressure in the brake system and the stored pressure in the brake accumulators.

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Illustration 6	g01061275

At the center axle, disconnect tube (a) and hose (b) from elbow (c). Remove the elbow from bracket (d) .

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Illustration 7	g01061276

Install tee (19) into bracket (d) with washer (39) and nut (32). Connect tube (a) and hose (b) to the tee. Connect tube (24) to the tee.

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Illustration 8	g01061277

Install hard washer (34), clip (36), clip (37), two hard washers (38), nut (40) and bolt (43) in order to secure tube (24) to bracket (e) .

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Illustration 9	g01061278

Position bracket (22) and install two bolts (41) with two washers (38). Install elbow (18) with washer (39) and nut (32) into bracket (22) before connecting tube (24). Make sure that the elbow is pointing down approximately 45° before tightening nut (32) and connecting hose (27) .

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Illustration 10	g01061309

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Illustration 11	g01061700

Position bracket (16) onto the axle housing and install two bolts (44) with washers (38). Install tee (25) into the bracket with two washers (39) and nut (32). Connect hose (27) to tee (25). Connect tube (12) for the right side to the tee and connect tube (13) for the left side to the tee.

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Illustration 12	g01063679

Install clip (36), clip (37) , bolt (49), hard washer (8) and hard washer (30) in order to secure tube (13) to the left side of the axle housing.

Repeat step 13 in order to secure tube (12) to the left side of the axle housing.

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Illustration 13	g01063680

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Illustration 14	g01063681

Install connector (17) into the manifold (7). Position the manifold on the left side of the axle housing before installing bolt (46) and hard washer (48). Make sure that the connector is facing toward the center of the axle housing and that the small threaded hole on the side of the manifold is facing upward. Connect tube (13) to the connector.

Install flared insert (6) into the small threaded hole which is facing the wheel hub before installing plug (1). Install flared insert (6) into the manifold on the left side of the axle housing before installing tube (15) between the manifold and service brake (23) .

Repeat step 15 and step 16 in order to connect tube (12) and install tube (14) for the opposite side.

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Illustration 15	g01061707

Position guard (20) and install boss (5), bolt (42), two washers (47), boss (2) and bolt (45) in order to secure the guard to the right side of the axle housing.

Position guard (21) and install boss (5), bolt (42), two washers (47), boss (2) and bolt (45) in order to secure the guard to the left side of the axle housing.