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A What issues arise from improper bolt tightening methods in construction machinery, and why must specified tightening requirements be followed?
In construction machinery, most fixing or connecting bolts (e.g., fuel injector bolts, cylinder head bolts, connecting rod bolts, flywheel bolts) have strict requirements for tightening—including specified torque, angle, or sequence. However, some maintenance personnel mistakenly view bolt tightening as a trivial task and ignore these standards. They may fail to follow the required torque/sequence (or even be unaware of such requirements), refuse to use torque wrenches, randomly use extension rods, or rely on “feel” to tighten bolts.
This improper practice causes inconsistent tightening torques. Insufficient torque makes bolts prone to loosening, which can damage cylinder gaskets, loosen bearing bushes, and cause oil/air leaks. Excessive torque can stretch, deform, or break bolts—and may even damage threaded holes.
To prevent mechanical failures from incorrect torque (insufficient or excessive) or wrong tightening sequence, bolts must be tightened strictly per the manufacturer’s specified torque and sequence during maintenance.
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A Why is it important to use correct maintenance methods for construction machinery, and what problems can arise from improper "makeshift" repairs?
Using correct maintenance methods is crucial because many maintenance personnel rely on improper "emergency" or makeshift approaches (prioritizing quick fixes over addressing root causes), which leads to long-term issues.
Examples of problematic practices include:
“Welding instead of proper repair”: When components like hydraulic cylinder ear ring threads or piston rods are damaged, direct welding (instead of repair) damages hydraulic cylinder oil seals, causing severe oil leaks and making seals unreplaceable.
Blindly increasing system pressure: If a working device moves slowly or stiffly, raising system pressure without diagnosing the fault damages oil seals, pipelines, and hydraulic components.
Over-adjusting diesel engine fuel systems: Artificially increasing fuel injection pump supply or injector pressure (to make engines “more powerful”) causes improper operation.
Such makeshift methods only provide temporary solutions. To ensure long-term reliability, maintenance personnel must identify faults at their root and use proper repair techniques.
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A Why does neglecting "minor" components in construction machinery maintenance increase malfunctions?
During maintenance, some personnel prioritize major components like fuel injectors, fuel pumps, pistons, cylinder liners, hydraulic oil pumps, control valves, braking systems, and steering systems. However, they overlook "small parts" such as filters, relief valves, and various instruments. These workers mistakenly believe these minor components don’t impact machinery operation and that damage to them is insignificant as long as the machinery can run. In reality, the lack of maintenance for these "small parts" causes early wear and tear of the machinery, ultimately shortening its service life.
