Installation of Replacement Switches for the Travel Alarm on Mini Hydraulic Excavators{7429} Caterpillar

Mini Hydraulic Excavator:

301.5 (S/N: 3YW1-UP)

301.6 (S/N: BDH1-UP)

301.8 (S/N: BFA1-UP)

302.5 (S/N: 4AZ1-5998)

Introduction

Travel switches may fail on mini hydraulic excavators. An operator is normally alerted to the failure when the travel alarm fails to sound. The alarm may sound intermittently. Some common causes of failure are the entrance of dirt into the switch, a bent roller arm, or a loose cam. The switch is an option that is not installed on all machines.

An improved travel switch arrangement reduces the exposure of the switch to the types of failures that are listed above. These instructions detail the installation of the switch.

Installation Procedure For 301.5, 301.6, and 301.8 Mini Hydraulic Excavators

Note: This procedure is used for all machines as a field repair only. This arrangement has never been offered from the factory.

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Illustration 1	g01185974
This is the original location of the travel alarm on 301.6 machines. (A) Limit switch assembly (B) Harness

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Illustration 2	g01183090
(1) 132-7077 Limit Switch As (2) 150-6257 Bolt (3) 253-4800 Link (4) 256-4605 Plate (5) 3C-6969 Nut (6) 5H-6555 Lockwasher (7) 9X-2042 Screw

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Illustration 3	g01183081
(1) 132-7077 Limit Switch As (2) 150-6257 Bolt (3) 253-4800 Link (4) 256-4605 Plate (5) 3C-6969 Nut (6) 5H-6555 Lockwasher (7) 9X-2042 Screw (C) Existing bolt for the mount

1. Remove the plate from the floor of the excavator in order to gain access to the main valve assembly.

2. Remove the existing hardware for the switch (A) .

3. Remove the existing links from the main valve. Install links (3). The notched end should be installed on the valve with the notch, facing upward.

4. Mount plate (4) in position with the existing bolt (C). Refer to illustration 3.

5. Drill and tap the frame at location (D). Use a 8T-3081 Tap or an equivalent.

6. Mount limit switch assembly (1) to the plate. Use bolts (2), washers (6) and nuts (5). Position the switch in order to activate the alarm when a travel lever is operated.

7. Connect the switches to the existing harness (B) .

8. Secure the assembly with screw (7) .

Installation Procedure For 302.5 Mini Hydraulic Excavators

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Illustration 4	g01184119
(1) 132-7077 Limit Switch As (2) 237-3736 Bracket (3) 3C-6969 Nut (4) 5C-9553 Bolt (5) 5H-6555 Lockwasher (6) 6V-9505 Screw (7) 8T-4205 Hard Washer (9) 163-7783 Link

1. Remove the plate from the floor of the excavator in order to gain access to the main valve assembly.

2. Remove the existing hardware for the switch.

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Illustration 5	g01189080
(A) Location of hole for "M6" bolt (B) Location of hole for "M6" bolt (C) 24 mm (0.9449 inch) (D) 103 mm (4.0551 inch) (E) 20 mm (0.7874 inch)

3. Drill and tap two holes at location (A) and (B) into the base plate of the valve. This will allow the mounting bracket to be attached. Use a 8T-3081 Tap or an equivalent.

4. Attach bracket (2). Use bolts (4) and hard washers (7) .

5. Remove the existing links from the main valve. Install the notched links (9). The notched end should be installed on the valve with the notch, facing upward.

6. Mount limit switch assemblies (1) to the plate. Use the screws (6), washers (5) and nuts (3) that are provided. Position the switch in order to activate the alarm when a travel lever is operated.

7. Connect the switches to the existing harness.