Description

Koehring 6620-II, 6620-LC Parts Catalog

If you’re trying to rebuild a Koehring 6620-II, 6620-LC Parts Catalog without the factory parts catalog, you’re burning time and money. I’ve seen guys order a “crawler shoe assembly” off a generic parts list and end up with 23.6-inch shoes when the machine needed 31.5 – and that’s a week of downtime and freight charges. This 113-page Parts Catalog is the only document that ties every part number, description, and serial number range to the actual engineering print. No aftermarket reprint. No copy. OEM data from Koehring Cranes & Excavators.

Crawler & Carbody: Track Assembly Details

The catalog opens with the crawler and carbody group – Group G in the table of contents. Need to tell apart a master link right-hand from left-hand? Page 1.2 lists every component: 47 track pins, 192 shoe bolts, the master pin assembly, and the bushing. If you’re swapping tracks on your 6620-II or 6620-LC, you need those exact part numbers – not a “compatible” substitute. The shoe options are broken out by width (23.6 in. and 31.5 in.) and type (flat, triangular). Even the lock washer part numbers change at certain serial breaks.

Upper Engine, Fuel Tank – What the Parts Catalog Shows

Moving to the upper structure, this group covers everything from the Engine mounts to the Fuel tank components. You get part numbers for fuel lines, tank caps, filters – not generic “fuel system” items but the exact Koehring part, referenced to serial number. If your 6620-LC has a fuel leak, you look up the fitting by reference number and order the correct OEM part. No guesswork.

Swing System and Pump Drive: Rotating Assemblies

The swing system and pump drive are separate groups in this catalog. Each page lists bearings, seals, gears, and housings with manufacturer part numbers. When you’re rebuilding the swing gearbox, you need the correct floating seal – page 5 shows an O-ring G75-70B and a floating seal assembly. Those are Koehring-specific, not off-the-shelf. The pump drive group covers the hydraulic pump mounting and coupler parts.

Hydraulic System: Hoses, Fittings, and Seals

Hydraulic system failures cost you hours. This group breaks down every hose, fitting, O-ring, and seal by reference number. If you’re replacing a cylinder hose, you match the part number from the manual and order the right length and fitting orientation. The catalog also includes the attachment hydraulic lines for excavator, clam, and dragline setups.

Source Validity: Why This Isn’t a Reprint

You see third-party parts catalogs online that claim “compatible” – they leave out the serial number breaks. This is the original Koehring publication, printed in the USA, with part numbers that match the factory build. If your machine’s serial number is 1175001 and up (6620-II) or 172101 and up (6620-LC), this is the reference. Aftermarket manuals often merge multiple revisions; this one keeps each part tied to the correct serial range.

If you work on older Koehring models, check the Koehring T-S44, 644 1974 Parts Catalog – Factory OEM Parts Reference for that era. For mid-70s machines, the Koehring S-155 1977 Parts Catalog – Factory OEM Parts Reference is a solid companion. And if you run a 366 hydraulic hoe, grab the Koehring 366 Hydraulic Hoe Parts Catalog – OEM Factory Specs.

For background on why factory specs matter in heavy equipment, see the Automotive Industry Overview and Automotive Industry Overview.

FAQ

Does this catalog include torque specs?

No. This is a parts catalog, not a service manual. It lists replacement part numbers.

How do I use the serial number breaks?

Each part listing has a “SERIAL NO.” column. For example, on page 1.2, the crawler shoe bolts change at serial 1174321 – note the nut part number shifts from 7302684 to 7306321. If you order the old nut for a later machine, it won’t fit. This catalog tells you exactly which part applies to your machine’s serial range. That’s why you need the serial number before ordering anything.

Can I get this as a printed book?

The manual is a digital access. Print it yourself or keep it on a tablet.

What sections are covered?

The catalog has groups for Crawler & Carbody, Upper Engine & Fuel Tank, Swing System, Pump Drive, Hydraulic System, Operator’s Cab & Controls, Mirrors, Marking, HVAC, Electrical, Tools, Excavator Attachment, Clam & Dragline, and Attachment Options. 113 pages total.

If you’ve got a Koehring 6620-II or 6620-LC on your lot, this catalog saves you from ordering blind. Link it to your workbench tablet or print the pages you need. Access the Factory Manual.