{"id":1999,"date":"2026-07-23T12:01:48","date_gmt":"2026-07-23T10:01:48","guid":{"rendered":"https:\/\/www.tfsoleodinamica.it\/case-study\/hagglunds-viking-mb84-motor-overhaul\/"},"modified":"2026-07-23T12:01:48","modified_gmt":"2026-07-23T10:01:48","slug":"hagglunds-viking-mb84-motor-overhaul","status":"publish","type":"case-study","link":"https:\/\/www.tfsoleodinamica.it\/en\/case-study\/hagglunds-viking-mb84-motor-overhaul\/","title":{"rendered":"H\u00e4gglunds Viking MB84 motor overhaul \u2013 offshore winch"},"content":{"rendered":"\n
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\u2699 Case Study \u00b7 Marine \/ Offshore<\/div>\n

H\u00e4gglunds Viking MB84 motor overhaul
an offshore winch back in service<\/span><\/h1>\n
\n Sector<\/strong> Marine \/ Offshore<\/span>\n Component<\/strong> H\u00e4gglunds Viking MB84<\/span>\n Application<\/strong> Marine winch<\/span>\n TFS service<\/strong> Overhaul \u00b7 Bench testing<\/span>\n <\/div>\n <\/header>\n\n
\"Rotary<\/figure>\n\n
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A H\u00e4gglunds Viking MB84 hydraulic motor<\/strong> fitted on the winch of an offshore vessel began showing abnormal noise and overheating. TFS overhauled it completely in the workshop \u2014 1,500 kg of radial piston motor \u2014 with original spare parts and final bench testing, returning it in 25 days.<\/p>\n\n

Noise and overheating on a H\u00e4gglunds Viking MB84 motor<\/h2>\n

The motor drives the winch of a vessel operating in the offshore<\/strong> sector, where a failure does not simply mean lost production: the vessel has to come back, and the intervention window depends on weather and logistics. The customer reported two symptoms, both typical of a rotary group that has accumulated running hours: increasing noise<\/strong> and overheating<\/strong> in operation.<\/p>\n

On a motor of this size, diagnosis is not done by ear. The Viking MB84<\/strong> is a low-speed, very high torque radial piston motor: 33,780 cm\u00b3\/rev displacement, roughly 538 Nm of torque for every bar<\/strong> of differential pressure applied \u2014 at 350 bar that means over 180,000 Nm at the shaft \u2014 running at 35\/70 rpm. A component weighing 1,500 kg<\/strong> that requires lifting equipment and a test bench able to take it.<\/p>\n\n

Disassembly and dimensional inspection of the rotary group<\/h2>\n

The motor was completely stripped down in the workshop. Inspection ruled out structural failure and found widespread service wear<\/strong> on the contact surfaces of the rotary group \u2014 the normal condition of a motor that has run many hours under load, and the direct cause of both the noise and the temperature rise.<\/p>\n

\"H\u00e4gglunds<\/figure>\n

The decisive step was not observing the wear but measuring it<\/strong>: every component underwent dimensional inspection and the tolerances were certified against the manufacturer’s specifications. This is what separates an overhaul from a repair \u2014 without instrumented measurement there is no way to establish which parts are still within tolerance and which must be replaced, and you end up changing either too much or too little.<\/p>\n\n

Overhaul with original H\u00e4gglunds spare parts<\/h2>\n

Based on the measurements, TFS defined the replacement plan and ordered the original H\u00e4gglunds spare parts<\/strong>, available in about 10 days<\/strong>. Parts within tolerance were kept; those out of specification were replaced. The motor was then reassembled following the manufacturer’s procedures.<\/p>\n

\"H\u00e4gglunds<\/figure>\n

Before delivery the motor went to the test bench<\/strong>, where flow, pressure, temperature, volumetric efficiency, internal leakage and noise were verified. The customer received the complete test report<\/strong> with the measured values: not a statement that a repair took place, but the recorded performance of the component going back into service.<\/p>\n\n

H\u00e4gglunds Viking MB84 returned in 25 days, bench tested<\/h2>\n

The motor went back to the customer 25 days<\/strong> after arriving in the workshop \u2014 ten of which spent waiting for the original spare parts \u2014 with performance verified on the bench and documented. The winch returned to service without replacing the motor: on a component of this size, and on a vessel in operation, an overhaul avoids both the cost of a new unit and the lead times a replacement would involve.<\/p>\n\n

\"Reassembly
The rotary group reassembled: radial pistons, rollers and cam tracks after dimensional inspection.<\/figcaption><\/figure>\n
\"Closing
Closing the housing and tightening to the torque values specified by the manufacturer.<\/figcaption><\/figure>\n
\"H\u00e4gglunds
The motor assembled and tested, ready for delivery.<\/figcaption><\/figure>\n\n

Why turn to a H\u00e4gglunds partner<\/h2>\n

TFS is a H\u00e4gglunds partner<\/strong> and works on the manufacturer’s radial piston motors \u2014 CA, CB, CBM, Compact, Atom and Viking series \u2014 with access to original spare parts and to the relevant technical specifications. The operational difference comes down to three concrete points:<\/p>\n