Description

Komatsu GD755-5R Installation Manual – Field Assembly Without Guesswork

If you have ever tried to install a cab on a motor grader using a generic diagram or a copy of a copy, you know the pain. Bolts that don’t match torque specs, missing sling points, and a cab that ends up crooked because the floor bolts were removed in the wrong order. That is why this Komatsu GD755-5R Installation Manual exists. It is 37 pages of factory-written procedure, from removing floor side parts all the way to checking every operation before the machine goes back to work. No shortcuts, no aftermarket copy – just the original OEM instructions that Komatsu issued for serial numbers 10001 and up.

The manual covers one specific job: installing (or removing) the operator cab on a GD755-5R motor grader. The machine weighs 21,700 kg and the cab itself is 860 kg. Sling it wrong and you are looking at damage or injury. This document tells you exactly which M16 eyebolts (part 04530-11628) to use and what the tightening torque is for each fastener – 54 to 88 Nm on the M16 bolts, with a target of 3.9 Nm for certain others. I have seen too many technicians guess a torque and then wonder why a joint leaks or a bolt backs out. Don’t be that guy.

Assembly Procedure: 8 Phases of Cab Installation

The table of contents lists eight numbered sections under Assembly procedure. It starts with 0000 Introduction – the basics like parking on flat ground, keeping a 6 m clearance above for cab hoisting, and reading the manual before you touch a wrench. Then comes the real work: 0010 Preparation – Removal of parts on floor side, 0020 Preparation – Removal of exterior parts under floor, 0030 Preparation – Removal of floor mounting bolts (page 15 if you want to skip ahead), and 0040 Preparation – Removal of parts on cab side. Each section is broken into sub-steps with images that show exactly which bracket or hose to disconnect. For a beginner, this sequence keeps you from having to backtrack because you forgot to unhook a hydraulic line.

Preparation Steps: Removing Floor and Cab Components

Before you install the cab, you have to take off everything that gets in the way. The manual walks you through the floor side parts first – things like the floor mat, foot pedals, and any trim that covers the mounting bolts. Then you drop the exterior parts under the floor (access panels, mud guards). I like that they tell you to label every electrical connection and hydraulic line. When you work alone, marking things saves your sanity. After those are out, you remove the floor mounting bolts – there is a specific order to prevent the floor from sagging and binding. The manual shows it in a diagram on page 15. Skip that step and you will fight a twisted frame for half an hour.

Installation of Cab: Slinging and Torque Specs

0050 Installation of cab is where the heavy lifting happens. The cab weighs 860 kg – that is the weight of a small compact car hanging from a chain. The manual specifies four M16 eyebolts and gives the correct slinging angles. If you need a refresher on lifting hardware, check out the Manual Transmission”>Manual Transmission section of a good automotive library – the principles are the same. Once the cab is in position, you torque the mounting bolts to 54–88 Nm (range) with a target of 78.5 Nm for the main bolts (page 5 lists the table). Use a calibrated torque wrench, not your calibrated elbow.

Connections with Chassis: Keeping It Factory Correct

After the cab is bolted down, you reconnect everything – 0060 Connections with chassis. This includes wiring harnesses, air conditioner lines, steering column joints, and any hydraulic controls that run through the cab. The manual shows each connection with a callout number so you can match it to your earlier markings. There is a section on checking that all connectors click home and that wires are not pinched between the cab wall and the frame. I have seen a pinched wire cause a fire on a grader – not a job I want to repeat. When you work on rolling stock like this, you never skip the visual inspection step.

Check of Each Operation: Why Your Safety Depends on Page 31

0080 Check of each operation starts on page 31. This is not a suggestion – it is a mandatory list. You check the blade controls, the steering, the brake system, the horn, the windshield wipers, and every function that passes through the cab. The manual tells you to do it with the engine running and the machine on flat ground. If something does not work, you trace it back through the connections. No shortcuts. If you have a transmission issue, the Manual Transmission”>Manual Transmission diagnostic processes on a separate manual will help, but for the cab install this checklist is your safety net.

Source Validity: OEM vs Aftermarket Documentation

This is a genuine Komatsu publication, not a third-party reprint. The cover says “Field Assembly Instruction” and the content matches the factory workflow. Aftermarket manuals often skip the safety warnings or use generic torque values that might work for a Volvo but not for this grader. This manual includes the specific Komatsu part numbers (like the M16 eyebolts 04530-11628) and the exact tightening torque range for each bolt size – down to the nominal diameter and target value. If you have ever seen a cab that rattles loose because the installer used a generic “tight enough” torque, you understand why OEM matters.

7 Systems Covered in 37 Pages

Each of the eight sections covers a specific system: floor removal, under-floor components, mounting bolts, cab-side parts, cab installation, chassis connections, restoration, and final checks. That is seven distinct systems (the introduction is not a system but the prep work) plus a restoration phase. The manual even gives the overall dimensions of the machine – overall length 9,580 mm, width 2,800 mm – so you can confirm you have enough space in your shop before you begin.

Related Manuals You Might Need

• Komatsu WD900-3 Installation Manual – Field Assembly Specs & OEM Torque
• Komatsu WF550A-3 Installation Manual – OEM Factory Assembly Specs
• Komatsu HD1500-5 Installation Manual – 199-Page Factory Assembly Guide

Frequently Asked Questions

Does this manual cover removing the cab too?

Yes. Page 2 of the introduction says “To remove the cab, perform the procedure in this manual in the reverse order.” So you can use it for both installation and removal.

What torque values are specified?

The manual gives a range for M16 bolts: 54 to 88 Nm. It also lists target torques for smaller nominal diameters like 6 and 8 mm. You will find the full table on page 5. Use a torque wrench, not your gut.

Is this a factory manual or a reproduction?

It is an original Komatsu OEM PDF. The serial number range (10001 and up) matches the factory publication. No aftermarket edits, no missing pages.

Can I use this for a GD755-5E?

No. This manual is specifically for the GD755-5R model. The dash letter indicates a different cab or chassis layout. Using it on another variant could result in incorrect bolt holes or clearance issues.

If you are ready to work on the cab of a GD755-5R, stop relying on secondhand information. Access the Factory Manual now and keep it open on your bench. Every bolt, every connection, every torque value is exactly where Komatsu engineers put it. That is the difference between a job you are proud of and a job you keep fixing.