Squeal which is Caused by the Pressure Relief Valve on 301.6C, 301.8C and 302.5C Mini Hydraulic Excavators{5057, 5264} Caterpillar

Mini Hydraulic Excavator:

301.6C (S/N: JBB1-UP)

301.8C (S/N: JSB1-UP)

302.5C (S/N: GBB1-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solutions that are identified below.

Problem

On SOME machines, when the left hand console is placed in the RAISED position, a squeal is generated by the pressure relief valve in the hydraulic system.

Solution

A permanent solution to the problem is still in development.

• Replacing the 274-9264 Relief Valve has resolved the issue on some machines.

• Replacing the 244-6732 Control Manifold Gp has resolved the issue on some machines.

• Replacing the 1/4 inch line with a 1/2 inch line has resolved the issue on some machines.

A different type of valve is being investigated as a permanent solution.