Case Study
Volvo EC550 track frame removal with the MT-HTW-4500 hydraulic torque wrench
How M Mackay Engineering Ltd, in the United Kingdom, removed the track frames of a Volvo EC550 excavator, working on M36 bolts at 2,700 Nm with the MT-HTW-4500 hydraulic torque wrench: controlled torque, one operator, a 4.2 kg tool.
Client
M Mackay Engineering Ltd (United Kingdom)
Vehicle involved
Volvo EC550 crawler excavator, 55 t class
Tool used
MT-HTW-4500 hydraulic torque wrench – 1" square drive, 441–4,511 Nm, 4.2 kg
Joint
M36 bolts, specified tightening torque 2,700 Nm
01 — The machine
Volvo EC550, 55 t class
The job concerned a Volvo EC550 crawler excavator operated by M Mackay Engineering Ltd in the United Kingdom: the bolted joint between the track frames and the centre frame.
53.7–58 t
Operating weight
Volvo EC550E according to the manufacturer: a 55 t class crawler excavator.
M36
Joint bolts
Large-diameter bolts holding the track frames to the centre frame.
2,700 Nm
Specified torque
Value specified for this joint.
02 — The challenge
The challenge
On large excavators such as the Volvo EC550, a crawler of around 55 tonnes, the track frames are fixed to the centre frame with large-diameter bolts. In this case they were M36 bolts with a specified torque of 2,700 Nm.
A manual wrench
At these values it needs a very long lever and a lot of force, often in awkward positions under the machine.
An impact wrench
It gives no control over the torque applied.
Removal
A bolt that has been tight for a long time can need more torque than was used to tighten it.
03 — The solution
The Maucotools solution
The choice fell on the MT-HTW-4500, the 1" square drive hydraulic torque wrench in the MT-HTW series. Torque is set through the pressure of the hydraulic pump, with ±3% repeatability. How to choose the model by torque is explained in our guide on how to choose a hydraulic torque wrench.
Torque range 441–4,511 Nm
The required 2,700 Nm sit at around 60% of maximum torque: there is headroom to break the toughest bolts loose without working at the limit of the tool.
4.2 kg
It is the smallest model in the MT-HTW series that reaches this value: the MT-HTW-1800 stops at 1,795 Nm and would not be enough, while the MT-HTW-7500 weighs twice as much (8.4 kg).
04 — Procedure
Removal procedure
Setting the pressure
Pump pressure set from the MT-HTW-4500 torque/pressure table.
Socket and reaction
Fitting the 1" socket on the bolt head and resting the reaction arm against a solid point of the frame.
Breaking the bolts
Breaking the M36 bolts one at a time, with the same setting for the whole joint.
Removing the frames
Removing the track frames.
05 — Results
Results obtained
M36 bolts
2,700 Nm
Controlled torque, no makeshift levers or impact wrenches
Operator
Just one
With a 4.2 kg tool
Torque headroom
~60%
The required 2,700 Nm against the MT-HTW-4500's 4,511 Nm maximum
The M36 bolts were worked at controlled torque by a single operator with a 4.2 kg tool, with no makeshift levers or impact wrenches.
06 — In the field
In-the-field documentation
The MT-HTW-4500 at work on an M36 track frame bolt of the Volvo EC550. Photo: M Mackay Engineering Ltd.
Torque note: 2,700 Nm is the torque specified for this joint. For every application, always use the values and sequence given by the machine manufacturer.
Large-diameter bolts to tighten or break?
MT-HTW wrenches, impact sockets and the torque calculator: Maucotools controlled bolting for heavy-equipment maintenance. For flanged joints, see our guide to the star-pattern tightening sequence.