The Ring in the Undercarriage Frame Assembly May Crack on Certain Excavators{4150, 4151} Caterpillar

Excavator:

320C (S/N: GNG1-UP; BPR1-UP)

320C L (S/N: EAG1-UP; HKT1-UP; BRX1-UP)

320D (S/N: JFZ1-UP; JGZ1-UP)

320D L (S/N: MDE1-UP; MGG1-UP)

Introduction

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

Problem

Reports from the field indicate that the ring in the undercarriage frame assembly has cracked on a very small population of machines. The crack occurred on certain machines in a severe application with a high load factor and with high service meter hours. The crack is typically located on the outer circumference of the ring. Refer to Illustration 1 and Illustration 2.

Solution

If the ring in the undercarriage frame assembly is cracked, replace the frame with a new undercarriage frame assembly. If the frame is replaced, a minimum level of parts inventory is being maintained in order to minimize downtime. Dealers should continue to report the cracks in the ring through DSN and SIMS. Include a clear description of the failure in the report. The Product Support Group continues to closely monitor this issue.

The part numbers of the affected frames are listed in Table 1. The affected machines are listed in Table 2.

Illustration 1	g01620927
Undercarriage Frame Assembly (1) 4I-3020 Ring

Illustration 2	g01620921
Undercarriage Frame Assembly (A) Typical crack