Fixing a Track Carrier: How to Repair a Cracked Weld for A Hydraulic Tank

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We recently purchased a Morooka MST 3000VD tracked dumper at auction, but before releasing any new piece of equipment to our fleet for rent or purchase, our team follows a 19-Point Inspection to be sure each unit is ready to roll at peak performance. Upon our incoming inspection our team found a crack in the top of the hydraulic tank that was allowing water to seep into the tank. If not cared for immediately it would cause the engine to cease and require a total engine replacement.

Through the diagnosis process, our mechanic determined that the best way to properly repair the crack in the hydraulic tank would require removal of previous weld attempts and to lay a fresh weld.

Each application varies in mechanical properties such as required strength, ductility and wear resistance which makes choosing the correct replacement/filler material critical. An exact material match, that meets or exceeds the parent materials strength, ensures weld quality and longevity, and avoids premature failure and unwanted downtime.

To improve the integrity of the repair, our team elected to use an MIG weld application. In MIG the arc is formed between the end of a small diameter wire electrode fed from a spool, and the workpiece. This type of welding application allows the welder to work in more confined spaces, providing better weld pool visibility and better control.

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Here’s how we tackled this repair project:

Once we determined the type of repair that needed to happen, our team completed the following steps to bring this Morooka back to life.

  1. Remove the hood - remove the bolts using a drill, with a forklift and safety precautions, a team of guys can move the hood onto palettes on the forklift.
  2. Take off the air intake – the intake sits right above where the crack was, so it needs to come off in order to fully access and repair our problem.
  3. Drain the hydraulic fuel – water leaking in from the crack caused rust and corrosion to contaminate the hydraulic fuel, so it had to be drained regardless. But for safety precautions, such as the grinding and welding right above the tank, a full tank would not be safe. After draining it with a transfer pump for the majority of the fuel, the rest can be emptied by removing the panel under the tank.
  4. Grind down the old weld – because of past welds, grinding the surface clean will ensure the weld is applied properly and provides a strong fix to the crack. In this case a die grinder is used to valley out the crack. This allows the weld to sit deeper in the groove and durable and watertight repair.
  5. Weld it back up – in this case, the best solution was to do three passes on the weld after removing so much of the original material; the first to replace the original material; the second to repair the crack; the third an aesthetic choice to make sure it looked clean and married the first two together.

Watch the process here:

Preparation of the Weld Joint

Cleanliness of the welding joint is critical. While some welding processes are more forgiving than others, it’s never wise to leave any contaminants behind. All rust, oils and paints must be ground or wiped away prior to welding – failure to do so will lead to a failed or weakened weld.

Tools / Supplies Needed for this Weld:
  • Welding Machine / Welding Accessories
  • Power Source
  • MIG Welding Wire
  • Wire Feed System
  • Electrode Wire
  • Shielding Gas
  • Metal Cutting Tool
  • Angle Grinder
  • Safety Gear – Like Gloves, glasses and Flame-resistant clothing

In this hydraulic tank repair video, Brandon fixes a cracked weld that was letting water in the tank and causing contaminated hydraulic fuel. If the crack isn’t fixed right away, the Morooka track carrier will become inoperable!

Once the weld has set, this unit will go over to our paint shop for a fresh coat and be on the road it is next job site.

Keeping your heavy equipment in top operating condition is one of the best ways to minimize downtime and maximize profits on any jobsite. Our 19-Point Inspection ensures every unit is ready to roll at peak performance before it ever enters our fleet. Proper service checks can prevent unexpected breakdowns that could keep your equipment out of commission and cause unnecessary expenses.

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Check out the video to see how our heavy equipment mechanic works to fix the cracked weld in a Morooka MST3000 hydraulic tank!


Follow along in this video to learn his process!


Our mechanics work on dozers, loaders, excavators, dump trucks, and much more, providing prompt and reliable maintenance to extend the life of any machine.

Got a piece of construction equipment that needs some TLC?

Call Newman Tractor today for your service needs @

859.888.1813 or visit

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Date: 06.30.2022
Topics: Equipment Tutorials