Gradall G-660 1974 Parts Catalog

You’re staring at a busted hydraulic line on a G-660 from the early ’70s, and the part number’s rubbed off. The aftermarket book you’ve got lists something close but doesn’t match the mounting flange. That’s wasted time and money. This Gradall G-660 1974 Parts Catalog is the original factory document – 194 pages of exploded views, OEM part numbers, and the exact callouts Gradall’s engineers put on paper when this machine was new. I’ve been turning wrenches for 28 years, and I’ve seen too many shops burn billable hours chasing wrong parts because someone bought a reprint that skipped pages. This isn’t that.

What This 1974 Parts Catalog Covers

The manual covers the upperstructure for G-660 hydraulic excavators built from Lot 1 through Lot 56. That’s a specific range – your machine’s lot number is stamped on the name plate. Page 2 of this catalog tells you to refer to the correct repair parts plate for your lot number. If you skip that step, you’ll end up with a clutch assembly or swing motor that doesn’t bolt up. The catalog includes everything from the cab assembly (section 8) and booms (main and telescope, sections 4 and 5) to the control rod assembly (section 29), foot pedals (section 29), and the fuel tank (section 7). It lists part numbers for cylinders – boom (section 26), hoist (27), tool (28) – and all the hose circuit breakdowns: boom circuit (17), pump circuit (15), swing and swing brake circuit (16), heat exchanger and dump circuit (21), hoist circuit (19), tilt circuit (18), tool circuit (20). The alphabetical index on page 3 lets you find any component fast. You want the bell housing? Page 1 of the index points you to section 14. Clutch assembly? Same section. That index saves you flipping.

Why Is This Manual Different from Aftermarket Copies?

I’ve had customers bring in third-party parts books that list a Caterpillar 11D power unit but omit the critical note about serial number breaks. This catalog is original Gradall – published in 1974 by The Gradall Company, 406 Mill Avenue S.W., New Philadelphia, OH. It includes the exact repair parts plates for all standard attachments, and it forces you to confirm your lot number before ordering. Aftermarket outfits often scan the plates at low resolution, blurring the tiny font that distinguishes a 11E from a 11F power unit. That’s a costly mistake. This manual gives you the same pages a Gradall distributor uses. It also includes the remote control section and the chassis ID for the crawler carrier. You won’t find those in a generic hydraulic excavator handbook.

194 Pages of Factory Data

194 pages sounds like a lot, but every one of them carries a purpose. There’s no filler. The power unit breakdowns cover Caterpillar 11D, 11D-1, 11E, 11F, 11G; Cummins 11H, 11J, 11K, 11L; General Motors 11D, 11D-1, 11E, 11F, 11G; and International 11, 11A, 11A-?. Each one has its own parts plate. The reservoir assembly (section 12), motors swing and tilt (section 10), manifold assembly (section 22), and manifold accessories (section 23) are all laid out with callout numbers that match the physical part. If you need a replacement hose for the boom circuit, you find the exact routing and fitting spec on the hose and tubing plates. No guesswork.

Match Your Lot Number Before Ordering Parts

Page 2 of this catalog states: “When more than one parts plate is included for a particular unit, be sure the lot number at the top left of the plate covers the lot number of your machine.” That’s the rule. I’ve seen a guy order a full bucket linkage (section 33) only to discover his G-660 had a later lot that used a different pin diameter. The catalog covers that – if you check the lot range on the plate. The same applies to the inside hose trough (section 4) and the cab assembly (section 8). Don’t assume; verify. The serial number of your Gradall appears on the machine name plate. Record it inside the front cover of this manual like Gradall intended.

Attachments and Booms: What’s Included

The catalog covers attachments on sections 34, 35, 36, 37 – these are the standard Gradall implements for the G-660. The main boom (section 4) and telescope boom (section 5) are shown with every bushing, pin, and wear pad. The cradle (section 3) and bucket linkage (section 33) are included. If you’re rebuilding a boom cylinder, the cylinder plates (sections 26-28) give you seal kit part numbers and the exact port configuration. The choke/throttle cable (sections 30, 30A) and instrument panel assembly (section 30) round out the controls. This is the only source for part numbers that match the 1974 production run.

Frequently Asked Questions

Does this catalog cover the carrier (truck) as well?

No. The carrier parts and service manual is a separate binder. This catalog covers only the upperstructure (Lot 1-56) and includes the remote control and crawler ID sections.

Will this work for a G-660 built after Lot 56?

No. The manual explicitly states it covers starting Lot 1 through Lot 56. Later lots used different part numbers. You need the later supplement.

What if my lot number is missing from the machine plate?

Call your local Gradall distributor. They can trace the serial number to a lot range. Without the lot number, you risk ordering the wrong parts. This manual’s plates are organized by lot, so you cannot safely substitute.

Are the part numbers still available from Gradall?

Many of the original numbers have been superseded. This catalog gives you the base number your distributor will need to cross-reference. Some wear parts – seals, hoses, filters – are still stocked. For obsolete parts, the exploded views help you identify dimensions to source equivalents.

You need the factory document that matches the machine on your lift. This 1974 Gradall G-660 Parts Catalog gives you the lot-specific part numbers, the correct repair plates, and the exploded views that tell you how everything goes together. Automotive Industry Overview and Automotive Industry Overview can give you background on construction equipment history, but when you’re holding a wrench, you want the original source. GRADALL G660 Upperstructure Service Manual complements this parts catalog with service procedures. If you need related manuals for other Gradall models, check Gradall 534 and 534B Service Manual or Gradall XL4210II 2006 Service Manual. Download the Factory Manual and get the right parts the first time.