Description

Thomas ProTough 1700, 173 HLS 1999 Parts Catalog – The One You Print and Keep

Let me guess — you’ve already wasted an afternoon digging through aftermarket parts lists that give you a fuzzy picture and a part number that doesn’t cross to anything you actually need. I’ve been there. That’s why when I see a Thomas ProTough 1700, 173 HLS 1999 Parts Catalog from the factory, I stop scrolling. This isn’t a reprint of a reprint. This is the original 123-page document Thomas Equipment Ltd. published in 1999, covering serial numbers LK001900 to LK002799. If you work on these loaders, you need the part numbers that come from the same drawing board the machine was built on.

Fuel System: 1.1 and Why It Matters

Start with the Fuel System. Section 1.1 in the MAINFRAME chapter gives you the exploded layout of the fuel tank, lines, and shut‑off petcock. Page 3 of the manual tells you exactly where the serial number is stamped — inside the rear door, right side, next to that fuel line shut-off petcock. That’s the first place you look when a part number doesn’t match. If you’re chasing a leaky fuel line or a clogged pickup, you get the OEM part number from this catalog, not a guess from a parts counter.

Hydraulic System Breakdown – Boom Lift and Bucket Tilt

The Hydraulic System section (chapter 4) is where you’ll spend most of your time. It covers the oil reservoir (4.1), filter and cooler (4.2), boom lift circuit (4.3), lift cylinder (4.4), bucket tilt circuit (4.5), tilt cylinder (4.6), auxiliary control (4.7), and four different control valve configurations — foot operated and hand operated, each with standard or solenoid auxiliary. That’s eight separate subsections for the valves alone. When a seal blows on the tilt cylinder, you want the exact part number for that cylinder rebuild kit, not a “universal” that might fit. This catalog gives it.

3 Systems You’ll Reference Most Often

Controls (chapter 2): Right-hand and left-hand control levers, hand-operated controls, foot pedals, throttle, and the restraint bar. If the operator grip is cracked or a pedal linkage is bent, you get the factory part number.

Final Drive Transmission (chapter 3): Transmission housing, axle assembly, idler sprocket and drive chains, parking brake. These components take a beating in a skid steer. Don’t gamble on chain pitch.

Hydrostatic Drive System (chapter 5): Right and left hydrostatic drive circuits, hydrostatic pump, auxiliary gear pump, torque motor. That torque motor alone can cost you days if you order the wrong one. The catalog breaks it down by circuit so you don’t mix sides.

What Does the Parts Catalog Actually Cover?

Beyond the big systems, it hits the details that eat up shop time: boom arms and pivot pins (1.4), R.O.P.S. assembly (1.5), boom supports (1.6), shields (1.7), insulation (1.8), seat and seat belt (1.9), boom lockdowns (1.10), decals and paint (1.11), wheels and tires (1.12), electrical wiring for R.O.P.S. and engine (6.1–6.2), engine equipment including air cleaner, exhaust (STD and CE), universal joint, radiator and mounts (7.1–7.5), and optional equipment like cab door, heater, windows, hi‑flow hydraulics, auto shutdown system (8.1–8.5). The Numerical Index (8.6) and Quick Reference Maintenance List (8.7) save you from flipping blind.

Get the Right Part Number the First Time

Ordering a part blind costs money. This catalog is your only shot at a correct OEM number for a Thomas ProTough 1700 or 173 HLS. Skip the aftermarket compilations — they transpose numbers, drop supersessions, and leave you holding a wrong box. The factory manual doesn’t do that. It prints the part number next to the exploded view so you can see exactly what you’re buying.

Source Authenticity: Factory Print, Not a Copy

This is a scan of the original Thomas Equipment Ltd. publication printed in July 1999 (Publication No. 46848). Inside the first pages you’ll find the full warranty statement — the one that reminds you that reading the manual is a condition of sale. That’s not fluff; that’s legal language Thomas used to protect themselves and to push you to use the right procedure. You won’t find that in a third-party reprint. The serial number location diagram on page 3 is clear enough that you can confirm your machine’s range before you buy a single bolt.

FAQ – Common Questions About This Parts Catalog

Does this manual include torque specs or repair steps?

No. This is a parts catalog — exploded views, part numbers, quantities, and reference numbers. It does not contain service procedures, torque values, or diagnostic steps.

What serial numbers are covered?

LK001900 to LK002799. Check your machine’s serial number plate (rear, right side) or the stamp inside the rear door next to the fuel shut-off petcock. If yours falls outside that range, some part numbers may be superseded.

Can I use this for the 173 HLS II or later models?

The 1999 catalog is specifically for the 173 HLS (Series III based on the TOC index) and ProTough 1700. Later models such as the 173 HLS II have different design revisions; you should get the factory catalog for your specific year and series. See related manuals below.

How do I find the part number for the hydraulic filter?

Go to the Hydraulic System chapter, section 4.2 (Hydraulic Filter and Cooler). The exploded view shows the filter element, head, and any adapters. Each item has a reference number that maps to the parts list. Write down that number and order from Thomas or a dealer — it’s the OEM filter for your machine.

Related Manuals for Thomas Loaders

• Thomas 175 & ProTough 1700 Parts Manual
• Thomas T-233 HD, T-203 HD, T-183 HD, T-173 Parts Catalog – OEM Parts Manual
• Thomas 173 HLS II 1996 Parts Catalog – Factory OEM Manual

If you want to understand how that Internal Combustion Engine works alongside the hydrostatic drive, or how the electrical system relates to a CAN Bus Network (though this loader predates CAN), the factory parts catalog is still the foundation. Access the Factory Manual and print it — you’ll reach for it before you touch a wrench.