This video documents the comprehensive repair of a hydraulic auger drive head from a 5-tonne excavator, primarily addressing a severely leaking oil seal and internal damage. The process involves extensive disassembly, which highlights challenges like a seized pin requiring cutting and hydraulic pressing, and the discovery of water contamination within the gearbox. A critical finding is significant wear on the output shaft's sealing surface, necessitating a custom solution. The repair includes precision machining of the output shaft to accommodate a new, custom-made seal with an undersized inner diameter and a nylon backup ring, along with the fabrication of a new hitch pin and reinforcement welding on the head bracket. The video concludes with the successful reassembly of the unit, showcasing the intricate mechanical work involved in such a heavy-duty repair.
Repairing a Heavy-Duty Excavator Auger Drive Head
0:13 Initial Assessment: The video begins with the repair of a hydraulic auger drive head from a 5-tonne excavator, focusing on a leaking oil seal and suspected internal wear.
0:53 Challenging Disassembly: Initial attempts to remove a seized pin for the head bracket prove difficult, eventually requiring cutting with an oxy torch and later a hydraulic press.
6:50 Internal Contamination Found: Upon separating the hydraulic motor from the gearbox, water is discovered inside the gearbox, indicating a significant contamination issue.
8:02 Component Inspection: While needle roller and thrust bearings are found to be undamaged, the primary leaking seal at the output shaft is severely deteriorated and needs replacement.
9:32 Critical Shaft Wear Identified: The most significant problem is wear on the output shaft's sealing area, which necessitates a specialized repair approach.
10:01 Solution: Undersized Seal & Wear Sleeve: To address the worn shaft, a plan is made to use a new seal with an undersized inner diameter, likely combined with a wear sleeve, to create a perfect sealing surface.
13:34 Structural Reinforcement: The head bracket is reinforced by welding around its bosses to add extra strength, suggesting previous issues with the original design.
18:17 Precision Machining: The output shaft undergoes precise machining (turning down the diameter) to create the correct surface and dimension for the new custom seal.
23:56 New Pin Fabrication: A new hitch pin is custom-made, including chamfering and drilling bolt holes, to replace the original seized component.
27:56 Enhanced Seal Design: The reassembly incorporates a custom-made seal featuring a nylon backup ring, designed to provide better durability and potentially outlast the original seal.
30:32 Careful Reassembly: The process of reassembling the gearbox, motor, and housing is shown, emphasizing careful seating of the new seal and even tightening of bolts.
35:44 Successful Completion: The auger drive head is fully reassembled, reinforced, and repaired, ready to be returned to the customer.