The mobile crane LTM 1400-7.1 is one of Liebherr's flagship models, distinguished by its high load capacity and exceptional versatility. It is a machine used in various industries, from construction to the energy sector. Its D9508 A7 engine with a power of 450 kW provides powerful performance, enabling heavy work in challenging conditions. Due to intensive use, comprehensive engine repair is sometimes necessary. Below we present a detailed description of the D9508 A7 engine repair in the mobile crane LTM 1400-7.1.
Work Stages
Engine Disassembly
Disassembling the engine from the machine is a crucial stage that precedes thorough diagnostics and repair. This process is carried out using a crane provided by the client. Our service team will ensure the safe and precise disconnection of all accessory components, such as the cooling system, air intake, and other essential components. The engine is removed from the machine, and the components are properly secured to prevent damage during transport to the workshop.
Engine Verification in the Workshop
After transporting the engine to our workshop, we conduct a detailed verification of its technical condition. In the case of the D9508 A7 engine, which showed symptoms of power loss, we performed detailed tests to determine the cause. Damage was identified in the crankshaft-piston system, which required further regeneration work.
Repair of the Crankshaft-Piston System
The repair of the crankshaft-piston system in the D9508 A7 engine included the replacement of pistons, rings, bearings, and a thorough inspection of the crankshaft and connecting rods. During this process, we replaced worn components and also performed grinding of the crankshaft to restore its original parameters. Each component of the crankshaft-piston system underwent a detailed quality control to ensure optimal engine performance after the repair is completed.
Regeneration of the Cylinder Head and Fuel System
The cylinder head of the D9508 A7 engine was subjected to regeneration, including planning, replacement of valve guides, and valves. Additionally, we checked the fuel system, including the injection pump and injectors. These components were cleaned and tested on a test bench to ensure they would operate flawlessly after reassembly.
Engine Testing on the Dynamometer
After completing the repairs, the D9508 A7 engine was subjected to tests on our engine dynamometer. The tests were conducted under light load conditions, allowing for preliminary verification of the engine's operating parameters. After 16 hours of testing under light conditions, the engine was subjected to maximum load to check its ability to operate under heavy load. These tests are crucial to confirm that the engine meets technical requirements and provides adequate power.
Reassembly in the Machine
After successful tests, the D9508 A7 engine was reassembled back into the mobile crane LTM 1400-7.1. The assembly included precise connections of systems such as the cooling system, air intake, and other necessary connections. Each connection was checked for tightness to avoid any leaks. The service team also conducted thorough tests of the machine with the operator to ensure everything was working as expected. After positive test results, an assembly protocol was signed, and the client was informed about the need for the first inspection after 50 operating hours.
Summary
The repair of the D9508 A7 engine in the LTM 1400-7.1 crane was a comprehensive service that included disassembly, thorough diagnostics, regeneration of the crankshaft-piston system, cylinder head, and fuel system, as well as dynamometer tests and reassembly in the machine. Thanks to our experience and modern equipment, the engine was restored to full functionality. We recommend conducting the next engine inspection after 50 operating hours to ensure long-term reliability and high performance of the machine.
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