Later, after moving into technical management work and gaining broader vision, I came to realize that in manufacturing plants, the use of sledgehammers is strictly prohibited. One reason is that they increase labor intensity and safety hazards; another is that they do not comply with the requirements of standardized and normalized processes.

On assembly lines, dedicated fixtures are always used for installation. For example, a 20-ton machine can have its bucket installed by a single operator following the proper procedure. For this reason, I once took several colleagues to a plant site specifically to learn how one person could remove and install a bucket without using a sledgehammer.

From this experience, I designed and manufactured multiple fixtures for large-scale disassembly and installation in maintenance workshops (different from factories where fixtures are dedicated to one machine model; ours are universal). Examples include fixtures for hydraulic pumps, motors, cylinders, engines, and boom/arm assemblies. With these tools, such valuable and heavy components can be removed and installed easily—without sledgehammers or chisels. This is the correct disassembly and assembly process for components.

Nowadays, tools and fixtures are even more complete—the key lies in how to use them.

Example:
For hydraulic pump disassembly and assembly, some people still rely on manual lifting. Unless no other machine is available, this practice should not be supported. First, it risks injury; second, it cannot guarantee installation standards.

This brings us to the requirement of component assembly:
For complete components being installed on a machine (especially major ones), in addition to cleanliness, proper alignment is required. Many do not understand this—they think as long as it can be mounted, it’s fine. They fail to realize that improper alignment directly affects the service life and precision of the mating components. Some operators even notice after reassembly that the machine doesn’t run as smoothly as before—this is why.

Today, lifting tools are abundant and inexpensive. Even a simple tensioner strap costing only a few dozen yuan can replace unsafe manual handling. For example, when installing a hydraulic pump, the pump shaft must be coaxial with the engine crankshaft flywheel. The pump must be moved parallel to the engine until it smoothly engages the coupling buffer block, with its bolt holes aligned with the flywheel housing. It must never be pulled into place with bolts. If it does not align, adjust the lifting position and try again—that’s the purpose of the hoisting tool. Until all bolts are fully tightened, the hoisting device must not be released. This is the distinction between professional and amateur work. Releasing the hoist too early allows the pump to shift under gravity, resulting in eccentricity and premature wear.

These are not advanced technologies. The difference is that unprofessional workers often ignore them. Experts don’t talk about such “basic” issues because they seem too trivial—but they matter.

Other cases:

• Boom and arm hoisting (small arms): Practice shows that a single lifting point at the center of gravity with control ropes is best. A little push/pull and the pin can be smoothly installed. For heavier parts, multi-point rigging is required, and some slings must be adjustable in length.

• Bucket disassembly: As long as the center of gravity is found, one person can finish the job—even on 30-ton machines or with pins worn into steps (using work platforms or pits in the field). No sledgehammer needed.

• Swing reducer disassembly: Best done with another machine for lifting. The reducer must be evenly strapped, and jacking screws used to separate the housing flange from its seat before lifting. Otherwise, cases of fractured swing motor housings can occur.

• Counterweight disassembly: Factory-installed counterweights rarely have problems, but many fail after field disassembly because correct procedures were not followed. With such heavy parts, precise installation is essential; otherwise, the counterweight may drop off. Never skip proper lifting equipment for the sake of cost. Poor reassembly can damage mating surfaces, let in contaminants, and leave bolts appearing tight but actually loose—leading to irreversible damage. The same principle applies to large components such as fuel tanks: surfaces must be cleaned, derusted, and debris removed before reassembly.

Fastening requirements:
Bolts and pins must be secured per OEM requirements. I once saw a worker weld a loose boom pin directly onto the boom, even grinding it to look smooth. In reality, this damages the boom itself. Problems like these must be analyzed scientifically and solved at the root cause—not with brute force. The era of “just do it your way” is long gone.

When a part repeatedly falls off after reassembly, the cause must be carefully investigated instead of dismissing it as a “common fault.”

Even track assemblies have strict OEM standards: track alignment, roller parallelism tolerances, etc., must be met. Otherwise, premature wear occurs, and people wrongly blame spare part quality. When repairing bulldozers, we always ensured the chassis, rollers, idlers, and sprockets were all aligned and parallel—only then could straight travel and minimal wear be guaranteed.

For boom and arm bushings, many think they are just rough parts and don’t pay attention. In fact, they are critical and tricky. Improper handling leads to unreliable pin retention, which transfers stress to hydraulic cylinders, causing rod-end fractures. The mechanic then blames the cylinder instead of his own poor installation.

The same logic applies to radiators: cracks often result from looseness or vibration, not from poor quality. Replacing them with low-grade aftermarket parts only worsens the problem.