Description

Clark Equipment 280 III Parts Catalog – What Your Shop Needs

If you’ve ever chased a part number through three different aftermarket websites and still ended up with the wrong seal kit for a 280 III, you know why I’m writing this. I’ve been turning wrenches since before some of you were born, and I’ve seen what happens when a shop relies on generic parts lists for old construction equipment. You get the wrong brake chamber, an air valve that doesn’t match the mounting holes, or a hydraulic cylinder that’s off by half an inch. This Clark Equipment 280 III Parts Catalog from 1960s-era factory print is the only way to get it right the first time. 154 pages of genuine part numbers, exploded views, and cross-references that tell you exactly what bolts into what. No guesswork. No returns. Just the straight OEM data your shop needs to keep that dozer moving dirt.

Engine Accessories and Air Compressor Parts

Your 280 III could have a Cummins or a GM powerplant – the manual covers both, from serial 4MC102 up through 8MG999. Page 1 tells you exactly which machines are included. Under the hood, you’ll find the Air Cleaner Assembly (page 20), Air Compressor and Governor (pages 1–2), and all the engine accessories listed under ‘Accessories, Engine’ with references to pages 66, 72, 76. Need the fan hub or the exhaust piping? They’re in there. This isn’t a service manual – it’s a parts catalog that cross-references every component with the factory part number. If you’re rebuilding an engine or replacing a compressor, this book saves you the headache of ordering the wrong bracket.

Brake System Breakdown: Air Valve to Slack Adjuster

Air brakes on a dozer are simple in theory but brutal when parts don’t match. The manual dedicates multiple pages to the brake system: Air Brake Valve (page 85), Air Brake Pedal (page 85), Brake Air Chamber (pages 66, 71, 75), and the Slack Adjuster (page 85 as well). Page 73 covers the Front and Rear Brake Assembly. If you’ve ever tried to match a brake chamber to a mounting bracket using only a visual guess, you know why having the exact part number from page 73 matters. The manual also covers Brake Air Lines (pages 87, 89) and Parking Brake assembly (page 77). One piece of advice: always check the Slack Adjuster arm length against the diagram on page 85 before you order – the manual shows two different configurations.

Steering and Hydraulic Cylinder Parts

Steering on the 280 III uses a rear drive steer axle (pages 71, 72, 75, 76) and a front drive axle (pages 65, 66). The Axle Tie Rod is listed on pages 72, 76. For the blade hydraulics, you get three separate cylinder assemblies: Lift Cylinder (pages 112–113), Pitch Cylinder (pages 114–115), and Tilt Cylinder (pages 116–117). Each assembly page shows the cylinder body, rod, seals, and all attaching hardware as individual part numbers. If you’re replacing a blown seal on a tilt cylinder, look up the part number on page 116 instead of buying a cheap aftermarket seal kit that may not hold pressure. I’ve seen too many guys order ‘universal’ seals and end up with a leaky cylinder a week later.

Frame and Blade Assembly – Cutting Edges and C-Frame

The ‘C’ Frame and Blade Assembly is on page 7, including the Blade Cutting Edges and the Trunnion Bar (page 3). The manual also lists C-Frame Pipes and the Trunnion Bar separately. If you’re rebuilding a blade or replacing cutting edges, the part numbers on page 7 are the ones Clark used factory-fresh. Don’t trust a third-party website that says ‘fits 280 III’ – verify against this catalog. The Body Panels (page 5), Radiator Baffle (pages 8–11), and Bottom Tank (pages 12–15) are also covered. Every fastener, every bracket, every grommet is listed with a factory reference.

Wiring and Electrical Components – Battery, Horn, Ammeter

Electrical parts are often the hardest to cross-reference because connectors change over the years. This manual covers Battery, Battery Box and Horn (page 128), Battery Cables and Wiring (page 134), Ammeter (page 127), and the Starter Push Button (pages 124–125). The Back-Up Lamp is on page 5. If you’re chasing an electrical gremlin, the wiring diagrams are not included (this is a parts catalog, not a service manual), but having the correct part numbers for the ammeter, horn, and battery cables means you can order the exact replacement without pulling the harness out first.

4 Reasons to Trust This Parts Catalog Over Aftermarket

First: the manual was printed by Clark Equipment Company, not a third-party publisher. Second: every part number was verified against the actual production line – the serial number ranges printed on page 1 cover 280 III Cummins units from 4MC102 to 6MC999 and GM units from 4MG101 to 8MG999. Third: the exploded-view diagrams on pages like 73 (Brake Assembly) use numbered callouts that correspond exactly to the parts list. Fourth: you’re getting the same document that Clark dealers used in the ’60s – no guesswork, no ‘equivalent’ parts. If you’ve been burned by aftermarket catalogs that list ‘fits many models’, this is your insurance. Pair it with the Clark Equipment 75B 1989 Parts Catalog – OEM Factory Manual or the Clark Equipment 310, 310III Parts Catalog – OEM Factory Manual if you work on multiple Clark machines. For the older 12-series, grab the Clark Equipment 12E2E 1968 Parts Catalog – OEM Factory Manual. For a broader look at the industry, check the Automotive Industry Overview on Wikipedia.

Frequently Asked Questions

What serial numbers are covered in this Clark 280 III Parts Catalog?

280 III Cummins: 4MC102 to 6MC999. 280 III G.M.: 4MG101 to 8MG999. See page 1 of the manual.

Does this manual include torque specs for engine or brake components?

No. This is a parts catalog, not a service manual. It lists part numbers, exploded diagrams, and component references – not assembly torque values or repair procedures. If you need torque specs, you’ll want the separate service manual for the 280 III. But for ordering the correct parts – piston rings, main bearings, brake linings – this catalog is the only source you should trust. Aftermarket catalogs often list superseded or cross-referenced parts that don’t match the original Clark numbering. This manual keeps you on the factory spec.

Can I use this to rebuild the transmission or converter?

Partially. The manual lists transmission case (page 36), converter charging pump (page 61), converter oil filter cartridge (pages 55, 57, 59), and clutch assemblies (pages 44–45 for first, fourth, and input clutches). You’ll get the exact part numbers for bearings, seals, and friction discs. But for assembly clearances and shim stacking, you need the transmission overhaul manual.

How accurate are the part numbers after 50 years?

Clark superseded some numbers, but the manual gives the original factory part numbers. For older machines that are still in service, many of these numbers are still valid through aftermarket suppliers that manufacture to OEM specs. If you run into a discontinued number, the diagram helps you identify the correct replacement by dimension and position.

If you work on Clark 280 III dozers – or any Michigan line machine from that era – you need this book on your bench. It’s not a repair manual, but it’s the only parts reference that guarantees you’re ordering the correct factory part for the engine, brake, and valve systems. Access the Factory Manual and keep it on your laptop or tablet. No more wasted trips to the parts store because the aftermarket catalog listed a ‘similar’ part. Get the OEM numbers.