Cylinder Assembly for the Service Brake Control Group May Fail on Certain 424B and 424B HD Backhoe Loaders {4269} Caterpillar

Backhoe Loader

424B (S/N: JRN1-UP)

424B HD (S/N: JRY1-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 have been received that the cylinder assembly for the service brake control group may leak at the push rod area due to seal failures on the machines listed above.

Solution

In the event of failure, follow the check list given below:

Check List for Brake Oil Leak

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Illustration 1	g06348943
(A) Inlet port (B) Outlet port (C) Under the reservoir (D) Bleeding tube joint

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Illustration 2	g06348945
View of area E (F) Push rod

1. Check for oil leakage at the locations mentioned in Illustration 1 and Illustration 2.

Check List for Inadequate Brake or Master Cylinder Malfunctioning

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Illustration 3	g06348949
(G) Reservoir (H) Hose assembly (J) Pedal assembly (K) Tube assembly (L) Elbow assembly

1. Check the tube assembly (K) for air entrapment. If air entrapment occurs, do air purging process in brake lines.

2. Check the brake pedals (J) LH and RH independently .

3. Check the master cylinder hose assembly (H) for any physical damages.

4. Check whether the water is entered in brake system ( while water washed / damaged reservoir cap)

5. Check for any noise or failure / replacement in brake unit or in rear axle.
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   Illustration 4	g06348952
   Wrong elbow assembly

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   Illustration 5	g06348951
   New elbow assembly (L) 148-8369 Elbow As

6. Check the hydraulic adapter as shown in Illustration 4 and 5. If it is a wrong elbow assembly, replace the wrong elbow assembly with the new elbow assembly (L) with the same part number.
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   Illustration 6	g06349526
   (M) 222-7875 Cylinder As

7. If any of above steps are not working, replace the cylinder assembly (M) with the same part number.

In the event of cylinder assembly failure, report the failure through the CPI feedback tool in Service Information Management System (SIMSi) referencing CPI number 381410. Retain the failed part for the factory analysis purpose.

In the event of failure, include below details with the failure report:

1. Customer:

2. Location:

3. Reported by:

4. Machine:

   • Backhoe Loader

5. Model:

   • 424B

6. Machine serial no:

7. Machine applications:

8. Failure date:

9. SMU at failure reported:

10. Works order no:

11. Part causing failure:

12. Part / component hours:

13. Problem: ( Nature of failure - Leak / Hard braking / No actuation / Physical damage )

14. Location of failure / Part causing failure:

15. Customer / Operator feedback:

16. Dealer service engineers observation: (Visual / Performance / Cut / Wear feedback)

17. Action taken: (Adjusted / Reworked / Replaced)

18. Attach the below pictures

    • Machine pictures

    • Application pictures

    • SMU gauge

    • Failure part and location picture - 1

    • Failure part and location picture - 2

    • Failure part and location picture - 3