Description

Terex Gyro 4020, Gyro 4518 2007 Service Manual

I’ve been turning wrenches since before most of you were born, and I’ll tell you straight: working on these Terex telescopic handlers without the factory paperwork is asking for trouble. The Terex Gyro 4020, Gyro 4518 2007 Service Manual is the only document I trust when I’ve got a Gyro 4020 or Gyro 4518 in the bay. Aftermarket binders? They guess at torque values, leave out bleed procedures, and skip safety lockout steps that’ll get someone hurt. This is the real deal — 296 pages from Terex themselves, first edition March 2007. You need the charge pressure for the steering system? It’s in here. The correct sequence for boom disassembly? In here. None of that “finger-tight then two more turns” nonsense. Factory spec or don’t bother.

Telescopic Boom Service: What This Manual Covers

The boom assembly chapter alone is worth the price of admission. Telescopic handlers take a beating, and the Gyro 4020 and Gyro 4518 share a lot of common components but have different reach capacities. This manual breaks down the boom extension cylinder removal, the wear pad inspection intervals, and the chain tensioning procedure. I’ve seen guys ruin a boom by not following the proper preload sequence — that’s a 10-hour job to fix. The manual’s step sequence saves you that headache. It also includes the specific thread locker compound required for the boom pivot pins. Don’t use the wrong one; the manual tells you exactly.

Torque Values and Fluid Capacities

Hydraulic system torque values are listed per fitting size — not guessed. You get the exact ft-lbs for the main pump lines, the drive motor flanges, and the steering cylinder ports. Same for the engine: head bolts, main bearing caps, everything. And the fluid capacities are in Imperial units: engine oil, transmission, hydraulic tank, coolant. No flipping through a generic book trying to find your model.

Does It Cover the Hydraulic System?

It covers the complete hydraulic circuit for both the Gyro 4020 and Gyro 4518. That includes the load-sensing pump, the control valves, the pilot lines, and the auxiliary circuit for attachments. The troubleshooting section walks you through low-pressure symptoms, sticking spools, and relief valve adjustment. There’s even a procedure for bleeding air from the boom cylinders after seal replacement. I’ve used that exact process to get a machine back in service in half an hour rather than nursing a spongy boom all afternoon.

3 Reasons the Factory Manual Beats Aftermarket

First, the wiring diagrams. The Gyro 4518 has a slightly different harness layout than the 4020 — the aftermarket books often combine them and leave you scratching your head. This manual separates them clearly. Second, the safety lockout procedures. Terex includes the specific steps for disabling the boom before any hydraulic work. I’ve heard of accidents from guys skipping that. Third, the OEM torque specs for the wheel lug nuts — the correct sequence prevents warping the brake drums. Aftermarket manuals? They’ll give you generic numbers that don’t account for the tapered wheel studs on these models.

Get the Right Specs Before You Start

If you’re planning an engine rebuild on a Deutz or Perkins (depending on the unit), the manual includes the injector timing procedure and the valve clearance specs. Don’t trust a YouTube video. The factory manual also gives you the complete parts breakdown for the driveline — the ZF transmission, the axles, the parking brake assembly. I keep a printed copy in my toolbox because when a job goes sideways, I don’t have time to scroll through a tablet.

Q: Will this manual work for the Gyro 4518 with a different engine?

A: Yes. The manual covers both Gyro 4020 and Gyro 4518 chassis, including the engine options specified by Terex.

Q: Does it include the electrical schematics for the cab controls?

A: The electrical section covers the entire machine, including cab controls, dashboard, and boom joystick. It shows wire colors and connector pinouts. There are multiple schematic sheets for each harness, and the manual notes the differences between early and late production units up to the 2007 model year. The wiring diagrams are critical for diagnosing intermittent faults — I’ve found open circuits in the harness that matched the drawings exactly. If you have a machine that cuts out when the boom raises, start with the boom limit switch circuit; the manual shows exactly where to probe.

Q: Is this a genuine Terex publication or a reprint?

A: It is the original factory service manual published by Terex in 2007. The documentation code is 57.4402.8200, first edition. No third-party reproduction.

Q: Can I use it for a pre-2007 Gyro 4020?

A: This manual covers from serial number 12888 for the 4020 and 12508 for the 4518. Older machines might have different specifications. Check your serial number against the range in the manual.

Also check the related manuals: Terex TS14G 1994 Service Manual – Factory Specs for Overhung Scraper, Terex TR60 1994 Service Manual – Factory OEM Specs & Safety, and Terex TR50 Service Manual – 364-Page Factory Shop Manual for Off-Highway Trucks. For background on the ZF gearbox, refer to the article on Manual Transmission. The lubrication guide for Manual Transmission is separate but always defer to the factory manual for your specific machine.

When you’ve got a Gyro 4020 or Gyro 4518 in your shop, you need the real specs. Access the Factory Manual before you start any repair.