Repair and service of Yanmar machines

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Professional diagnostics, efficient repair, and expert support at every stage

Professional repair of Yanmar machines

At our Yanmar machine service center, we eliminate costly downtime for your business thanks to immediate diagnostics and direct access to components. We restore the factory performance of hydraulic and drive systems in Yanmar SV series mini excavators (including SV16, SV18, SV26) as well as zero-tail-swing machines from the ViO line. By combining advanced workshop procedures with our own massive parts warehouse, we guarantee a lightning-fast response time, full purchase security, and uncompromising reliability of equipment on the construction site.

Trust the experts

Our team of Yanmar internal combustion engine experts

Our team of engineers and mechanics specializes in advanced repairs and overhauls of Yanmar power units, guaranteeing the recovery of full engine power without the risk of failure on the construction site. We perfectly understand the structural specificities of the three- and four-cylinder diesel engines of the TNV and TNE series, which power construction machinery worldwide. We focus on restoring ideal compression parameters and smooth operation in models such as the Yanmar 4TNV88 and 4TNV98. Thanks to our team's precise approach, we eliminate the problems of excessive smoking, power drops under load, and difficult starting, ensuring long years of trouble-free operation for your machine. In addition to mechanics, our team flawlessly diagnoses and calibrates Common Rail injection systems and inline pumps, using exclusively proven seals, plungers, and injector nozzles from our warehouse, giving you one hundred percent security for every completed repair.

 

Quality control and final testing on the dynamometer

Professional engine dynamometer

At our service center, the regeneration process of Yanmar engines ends with rigorous testing on a professional engine dynamometer, giving you the certainty that the power unit will withstand the toughest working conditions without the risk of failure during use. Every industrial and construction engine repaired by us, including the powerful four-cylinder Yanmar 4TNV88, 4TNV94, and 4TNV98 units and their turbocharged versions 4TNV98T, goes to this specialized test stand. The quality control we perform under real load conditions completely eliminates the risk of hidden assembly defects, guaranteeing uncompromising purchase security and the elimination of costly downtime on the construction site. During hours of testing on the engine dynamometer, our engineers thoroughly check the tightness of all systems – including the oil line, cooling system, Common Rail fuel system, and injection pumps. We test operating parameters under various loads, precisely monitoring RPM stability and performance under conditions close to real operation in heavy construction machinery. Thanks to such detailed verification, we have absolute certainty that every unit leaving the Wibako workshop operates according to factory parameters or exceeds them. Only after successfully passing all tests and generating a report is the Yanmar engine ready for installation in your machine or for safe and fast shipping.

 

When does your machine need service?

Symptoms of a damaged Yanmar engine

Ignoring the first symptoms of engine failure in heavy construction machinery leads directly to serious damage to the block or crankshaft, generating huge costs and long downtime on the construction site. If you notice any of the following behaviors in your excavator or loader, our team is ready for immediate, professional diagnostics and repair.


Pay close attention to the following disturbing symptoms:

Sudden power drop and lack of throttle response under load - most often indicates wear of the Common Rail injection system, loss of cylinder compression, or turbocharger failure in 4TNV98T engines.

Excessive smoke from the exhaust system - black smoke means improper fuel combustion or a problem with the EGR valve, while blue or white smoke is a signal that the engine is burning engine oil or that coolant is entering the combustion chamber.

Difficult engine starting, especially when cold - this symptom foretells low compression pressure in the cylinders, wear of pistons and liners, or a malfunction of the pumping sections in the injection pump.

Unnatural knocking, metallic noises, or excessive vibration - a critical symptom indicating worn-out connecting rod bearings, play in the piston pins, or damage to the timing system, requiring the machine to be shut down immediately.

Loss of coolant or oil, and rising oil level - a clear sign of damage to the cylinder head gasket, a cracked head, or a leak in the fuel pump, which risks seizing the engine unit.

Dashboard errors and drops in oil pressure - a lubrication pressure warning light that comes on when the engine is warm is an alarm signal indicating a worn oil pump or excessive clearance on the crankshaft.

Don't wait for a minor defect to turn into complete engine destruction. Contact our service center – we will bring your machine or the Yanmar engine itself to the Wibako workshop, conduct a verification, and restore it to full factory performance.

Over 30 years of industry experience

Our team of Yanmar power hydraulics experts

Our specialized team of hydraulic technicians at Wibako provides comprehensive regeneration and precise tuning of power hydraulic systems, effectively eliminating the problem of slowed operational movements or loss of pressure under load. We perfectly know the hydraulic architecture of Yanmar machines, in which advanced multi-piston systems and Load Sensing power regulation systems play a key role. Every day, our experts service and restore the factory efficiency of main hydraulic pumps, travel motors, and swing motors used in medium and large crawler excavators, such as the Yanmar ViO50, ViO57, ViO80 models, or wheeled B75 and B95 machines. Thanks to our team's multi-year experience, we eliminate internal leaks, noisy system operation, and asymmetry in track travel, which guarantees precise control and maximum breakout force at the bucket. We work on components from brands that supply factory hydraulics to Yanmar machines, such as Rexroth, Kayaba, or Nachi, utilizing a massive backing of parts available immediately from our warehouse. Every element of the system, from the main control valve to the final drives, is assembled by our mechanics while maintaining strict cleanliness standards, which combined with engineering knowledge gives you the certainty of safe and trouble-free machine operation in the toughest terrain conditions.

 

Computer testing and calibration of components

Professional hydraulic test bench

At Wibako, we possess professional diagnostic stations, including an advanced hydraulic test bench, which allows us to achieve uncompromising verification and testing of pumps and power hydraulic components before delivering them to the customer. Every piston pump, travel motor, or swing motor operating in Yanmar machines - from the ViO50 and ViO82 models to the wheeled B75 and B110 series machines - undergoes a rigorous load test after the regeneration process. Having such specialized diagnostic backing in our workshop eliminates the risk of installing a faulty component, guaranteeing you complete purchase security, flawless parameter stability, and the elimination of costly repeated machine downtime on the construction site. During final testing, we monitor real-time parameters such as flow efficiency, operating pressure reaching several hundred bars, and hydraulic oil temperature, which allows us to detect the smallest internal leaks. Crucially for Japanese hydraulic systems, we precisely calibrate Load Sensing pump regulators and control valves on the test bench, restoring their factory operating characteristics and ideal synchronization with the Yanmar engine. Only after generating an electronic report, which confirms in black and white the achievement of full efficiency and 100% volumetric performance, does the component leave our service center, ready for immediate installation or secure shipment to your company.

 

When to react to avoid downtime?

Symptoms of damaged Yanmar power hydraulics

At Wibako, we perfectly know the specificities of Japanese hydraulic systems used in models like the Yanmar ViO50, ViO57, ViO80, or wheeled B75. Quickly linking disturbing operational symptoms to a specific fault allows us to intervene immediately before a damaged component contaminates your machine's entire oil system with metal shavings.


Contact our service center if you notice the following symptoms in your Yanmar machine:

Weakening and clear slowing down of the machine after the oil warms up - a classic symptom of a drastic drop in the main pump's volumetric efficiency resulting from internal leaks between the cylinder block and the valve plate.

Travel asymmetry and the machine pulling to one side - indicates an uneven output of the pump sections, damaged relief valves in the control valve, or advanced wear of one of the travel motors along with the final drive.

Unnatural, noisy operation, howling, or metallic squealing of the pump - a symptom of cavitation, air in the system, or mechanical damage to the bearings and pistons in the hydraulic pump, which requires an immediate stop of the machine to avoid filling the system with shavings.

Lack of smooth movements and jerking of attachments under load - most often indicates misconfiguration or damage to the control valves of the Load Sensing system, which is responsible for the intelligent distribution of oil flow to individual operational functions.

Sudden, excessive heating of hydraulic oil - a signal that massive resistance or permanent internal leaks are occurring in the system, which drastically accelerates the degradation of seals and the lubricating properties of the oil.

Dropping of the excavator arm or lack of breakout force at the bucket - an evident symptom of leaks in hydraulic locks, worn seals on cylinder rods, or worn spools in the main Yanmar control valve.

If your machine shows any of these symptoms, do not risk a total seizure of the system. Hand over the component or the entire machine to Wibako - on our hydraulic test bench, we will precisely locate the source of the problem and restore the system's factory pressures and flows.

 

 

Professional technical assistance directly on your construction site

Wibako mobile service

We understand that a breakdown during a road or construction contract generates huge losses, which is why our mobile mechanics respond immediately, reaching the designated location with specialized service vehicles. We service medium and heavy Yanmar machines - from crawler models of the ViO50, ViO57, and ViO80 series, to wheeled B75, B95 excavators or articulated loaders. Thanks to the advanced equipment of our mobile workshops, we are able to carry out full computer diagnostics, locate the source of the fault, and perform most mechanical and hydraulic repairs directly in field conditions. Each of our service vehicles is an independent repair station, where Wibako engineers have professional measuring tools, mobile crimpers for hydraulic hoses, and sets of pressure gauges to measure pressures in Yanmar Load Sensing systems. On-site, we perform precise diagnostics of the vital parameters of 4TNV88 or 4TNV98 engines, verify the operation of hydraulic pumps, and efficiently replace damaged components, such as starters, alternators, injection system elements, or cylinders. Having the direct support of our massive Wibako stationary warehouse, mobile service technicians set out into action with a set of necessary, original seals and filters dedicated to the specific Yanmar model. In cases of complex failures requiring machining, our team efficiently dismantles the damaged hydraulic pump or engine, transports it to our headquarters for testing on the dynamometer, and after regeneration, installs and calibrates the component directly in your machine, giving you 100% security and continuity of operation.

 

Immediate Availability and OEM Certainty

Massive Parts Inventory and Official Partnership with Bosch and Motorservice

Wibako's own large-scale spare parts warehouse is the heart of our service operations, completely eliminating long wait times for components and drastically shortening the repair duration for Yanmar machinery. This powerful logistical independence also translates into the unrivaled efficiency of our mobile service team—following an initial phone verification or error code diagnosis, our mechanics retrieve precisely matched components from the warehouse and head directly to your job site with a complete repair kit. We provide you with uncompromising purchase security and lightning-fast 24-hour parts shipping, offering a full spectrum of solutions tailored to your budget: from brand-new elements and certified aftermarket alternatives to thoroughly tested and fully operational used parts. We build our market-leading position and technical authority on direct, official partnerships with global giants in the automotive and industrial sectors, being a proud partner of the Bosch and Motorservice brands. Thanks to this, we guarantee direct access to premium OEM components and genuine parts used for the factory assembly of four-cylinder Yanmar engines from the 4TNV88, 4TNV94, and 4TNV98 series. Our cooperation with Bosch allows us to supply and precisely calibrate components for advanced Common Rail injection systems and fuel apparatus, while our partnership with Motorservice provides us with continuous, direct access to perfectly engineered pistons, rings, bearings, and valves. By choosing Wibako service, you gain the certainty that only components with confirmed technical specifications are used in the repair of your ViO crawler excavator or B-series wheeled machines. Combined with the elimination of middlemen, this guarantees the highest durability of repairs and trouble-free equipment operation for thousands of engine hours.

 

 

 

Does every Yanmar engine repaired at Wibako undergo dynamometer testing?

Yes, absolutely every Yanmar engine undergoes a mandatory, rigorous quality control test on our in-house engine dynamometer following a major overhaul. During testing, we check the tightness of the lubrication, cooling, and fuel systems, while also monitoring RPM stability and performance under varying loads that simulate real-world operation in heavy construction machinery. The power unit is only cleared for release once a successful dynamometer report is generated, giving you 100% confidence that the engine has regained full power and is ready for immediate, trouble-free operation.

Where exactly is the Wibako headquarters located, and do I need to deliver the Yanmar machine in person?

You don’t need to arrange transport on your own—we have our own fleet of trucks and low-loader trailers, allowing us to pick up your Yanmar ViO excavator or just the damaged engine from anywhere in the country and safely transport it to our service center. Additionally, for minor hydraulic or 4TNV engine accessory faults, our mobile service team can carry out repairs directly at your construction site, eliminating the need for any transport whatsoever.

Do you provide a warranty for Yanmar engine overhauls and hydraulic pump remanufacturing, and for how long?

Yes, we provide an official warranty for all key repairs of Yanmar components, with the warranty period tailored specifically to the nature of the given system. We offer a full 12-month warranty on every major overhaul of Yanmar 4TNV series industrial engines, while providing a 6-month warranty on the comprehensive remanufacturing of main hydraulic pumps and travel motors.

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