Engine Overhaul of Liebherr D9508 A7 in LTM 1300-6.2 Crane

Overhaul of the Liebherr D9508 A7 engine in the Liebherr LTM 1300-6.2 mobile crane

Comprehensive service of the Liebherr D9508 A7 engine

The Liebherr LTM 1300-6.2 mobile crane belongs to the group of the largest six-axle mobile cranes used during the assembly of steel structures, construction of wind farms, implementation of industrial investments, and infrastructure works. Thanks to its telescopic boom, advanced LICCON control system, and high lifting capacity, the machine operates in the most demanding conditions, where drive reliability is of key importance. The chassis is powered by a Liebherr D9508 A7 diesel engine – an eight-cylinder V8 unit with a large displacement, designed to operate under high loads for thousands of operating hours.

An engine removed from a Liebherr LTM 1300-6.2 crane operating at an energy investment project near Katowice arrived at our service center. The operator reported a drop in oil pressure, metallic noises coming from the lower part of the engine, and a clear drop in performance while driving and relocating the machine. Initial diagnostics included oil pressure measurement, oil sample analysis, and filter inspection. The presence of a significant amount of metal shavings indicated wear on the bearings of the crank-piston system. Our mobile service dismantled the power unit using a crane provided by the customer, secured all installations, and transported the engine to our headquarters in Kojszówka.

Disassembly of the Liebherr D9508 A7 engine

Disassembly of the engine in the Liebherr LTM 1300-6.2 crane requires extreme caution due to the complex accessories and limited installation space. Mechanics disconnected the electrical wiring, fuel lines, cooling system, air intake, exhaust system, and all components interacting with the drive transmission. All lines were labeled and secured against contamination. After unscrewing the mounts, the engine was safely removed from the frame using the customer's crane in accordance with Liebherr service documentation.

Component verification

Upon delivery of the unit to the workshop, a full technical verification began. The engine was completely disassembled, and all parts were cleaned and subjected to detailed measurements.

The inspection revealed significant wear on the main and connecting rod bearings, as well as signs of overheating on the crankshaft journals. Verification of the shaft included measuring runout, checking journal dimensions, and inspecting the oil passages. The connecting rods were checked for straightness, twist, and dimensions. The cylinder heads underwent a leak test in a heated water bath, and the condition of the guides, valves, and valve seats was assessed. Additionally, the turbochargers, Common Rail high-pressure pump, injectors, alternator, starter, and other components were verified.

Engine remanufacturing and repair

The scope of the overhaul included a comprehensive rebuild of the entire crank-piston system. The crankshaft underwent professional grinding, after which new main and connecting rod bearings were installed. A complete set of pistons, cylinder liners, piston rings, and all sealing elements was replaced.

The heads were surfaced, and valve guides, valves, and seals were replaced. After completing the remanufacturing, a final leak test was performed. Injectors were checked on a test bench, while the high-pressure system was subjected to a full inspection of its operating parameters. The turbochargers and all accessories responsible for the correct operation of the unit were also verified.

During assembly, a set of new bolts, gaskets, and consumables compliant with the manufacturer's documentation was used. All components were assembled maintaining the appropriate tightening torques and technological procedures.

Test on the engine dynamometer

Every Liebherr D9508 A7 engine overhauled by WIBAKO undergoes mandatory testing on a professional engine dynamometer. This is one of the most important stages of the entire rebuild process, as it allows verification of the unit's operating parameters before its installation in the crane.

After completing the workshop assembly, the engine was installed on a test stand equipped with a complete cooling and fuel supply system, as well as a computerized system for monitoring operating parameters. The first stage included over 16 hours of operation at a load of approximately 20-30% of the nominal value. During this time, we monitored oil pressure, coolant temperature, oil temperature, boost pressure, Common Rail system parameters, and the stability of the engine control unit.

Subsequently, the load was gradually increased up to the maximum values specified by the manufacturer. Dynamic load changes were performed multiple times, observing the engine's behavior during rapid changes in rotational speed. Exhaust emissions, the tightness of all systems, and combustion parameters were also analyzed. Thanks to the dynamometer, it was possible to confirm the full efficiency of the unit before its return to the customer. This provides a huge advantage over repairs carried out without the possibility of an actual engine load, as any irregularities can be detected before installation in the machine. Upon completion of the tests, a full parameter report confirming the correct operation of the Liebherr D9508 A7 engine was prepared.

Engine installation in the Liebherr LTM 1300-6.2 crane

Following the completion of the tests, the unit was transported to the customer. The installation was carried out by our service technicians using a crane provided by the machine owner. The engine was precisely seated on its mounts, and then the electrical wiring, fuel lines, cooling system, intake, and exhaust systems were connected. Particular attention was paid to the correct routing of lines and the inspection of all connections.

Before the initial start-up, filters and operating fluids were replaced, the fuel system was bled, and a leak check was conducted. The first start-up took place in the presence of our mechanics and the crane operator. Subsequently, tests were performed during driving, hydraulic operation, and boom handling. After confirming the correct operating parameters, the installation protocol was signed, and the machine was handed over for further operation.

Engine maintenance after overhaul

The Liebherr D9508 A7 engine after the completed overhaul was covered by a warranty. We recommend performing the first inspection after 50 operating hours. During the visit, our service technicians replace filters, check the tightness of all connections, control the operating parameters of the engine, and inspect the condition of the accessories. Subsequent inspections are carried out every 250 operating hours, but no less frequently than once every three months.

Machines equipped with the Liebherr D9508 A7 engine

The Liebherr D9508 A7 engine is used in the largest machines from the manufacturer Liebherr, including mobile cranes, all-terrain cranes, and specialized machines designed for heavy load transport. Thanks to its high torque and high durability, the unit performs perfectly during long hours of operation under heavy loads, but after many thousands of operating hours, it requires professional remanufacturing performed in accordance with the manufacturer's technology.

Summary

The comprehensive overhaul of the Liebherr D9508 A7 engine carried out by WIBAKO restored the full functionality of the Liebherr LTM 1300-6.2 mobile crane. The combination of detailed diagnostics, comprehensive rebuild of the power unit, mandatory engine dynamometer tests, and professional installation ensures reliable operation of the machine for the next thousands of operating hours. Our mobile service carries out engine disassembly and assembly throughout Poland, transports units to Kojszówka, and performs comprehensive Liebherr engine overhauls.

Internal linking:
Liebherr engine overhaul
Liebherr mobile crane service
WIBAKO engine dynamometer
Mobile service for construction machinery