2005/04/04 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-UP)

303 CR (S/N: DMA1-UP)

303.5 (S/N: DCH1-UP; AFW1-UP)

304 CR (S/N: NAD1-UP)

304.5 (S/N: WAK1-UP)

305 CR (S/N: DSA1-UP; DGT1-UP)

An improved pin lock group is now available. The new pin lock group is an improved design that increases the durability.

The new pin lock group is adaptable to all of the excavators that are listed above. Refer to Table 1 for the new pin lock group for your machine.

A single lock assembly is adequate for most applications. However, Caterpillar recommends the use of two pin locks when the quick coupler is used with a hammer for long periods of time. Extended use of a hammer can cause damage to the pin lock. The new design will last longer than the old design, but both designs may be damaged by extended use of a hammer.

Note: Caterpillar recommends installing a second pin lock group on the coupler only if a hammer is used on the machine.

Certain couplers do not have a hole for the second pin lock hole. Refer to the following procedure in order to machine a second hole in the coupler.

Pin Lock Hole Installation Procedure

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Illustration 1	g01150066
(1) New hole (2) Existing hole

1. The centerline of new hole (1) must be within 0.25 mm (0.0098 inch) of the centerline of existing hole (2) .

2. Use the necessary procedures in order to machine the additional hole. Refer to Illustrations 1 and Table 2.

3. Drill hole (F). The diameter of hole (F) is 7 mm (0.276 inch). Drill the hole 30 mm (1.18 inch) in depth. Thread the hole with a M8 tap.

4. Clean the working area and check for a proper fit of the pin lock.