Description

Koehring 6633L, 6638L 1986 Parts Catalog

You’re standing at the parts counter with a machine down, a customer watching the clock, and a parts clerk asking for a part number you don’t have. That’s the moment you need the Koehring 6633L, 6638L 1986 Parts Catalog – not a scanned reprint from some third-party, but the exact factory document Koehring published in 1986. This Parts Catalog runs 15 pages, every one of them packed with OEM part numbers, exploded views, and supersession notes that tell you which part replaces what. Page 1 of the PDF lays out the swing and traction piping system – every elbow, hose, strap, and capscrew identified by factory part number. You don’t order a hose by measuring the length with a tape; you look up the OEM number and move on.

Wasted time on wrong parts is billable time you don’t get back. This catalog eliminates the guesswork. The hydraulic system sections on page 1 (swing & traction) and page 2 (attachment) give you the exact assembly breakdowns. Page 25.11A inside the manual shows the swing circuit with a note: “Parts shown supersede respective parts on pages 25.10 & 25.11.” That’s the kind of detail aftermarket junk leaves out. You get the full revision history – which supersedes which – so you never order a discontinued part.

Hydraulic System – Swing & Traction

Page 1 of this catalog covers the swing and traction hydraulic system for both the 6633L and 6638L models. You’ll find the OEM part numbers for the elbow (Part No. 376 1100), the three different hose assemblies (708 7431-102, 708 7425-21, 708 7429-74, 708 7429-21), the pipe spacer, the plate, and the capscrews with their lengths. The 5/8C capscrew calls out a 3-3/4 inch length – not “approx” or “similar.” Factory spec. That’s the difference between a seal that holds and a drip that brings the machine back next week.

Attachment Valve Assembly Details

Page 2 of the PDF takes you into the attachment hydraulic system. The solenoid valve, pilot valve, flow control valve – each one listed with its part number and quantity. You see capscrew sizes like 1/2C x 3-3/4 and 5/16C x 3-3/4, plus the corresponding nuts and washers. The exploded view shows the order of assembly. If you’re rebuilding a valve stack, this page tells you exactly which O-ring (Part No. 460V0005) and split flange clamps (1219-626, 363V6001) go where. No aftermarket catalog gives you this level of precision. Koehring 6633L 6638L 1985 Parts Catalog covers an earlier production run, but this 1986 edition incorporates the supersessions up to that date.

Why OEM Factory Specs Matter

I’ve seen too many techs trust a third-party parts list that swapped a 7/16C capscrew for a 3/8C because “they’re close.” That’s how you snap a casting or lose a pilot valve under load. This catalog comes from Koehring’s original print run. The part numbers are direct from the manufacturer’s engineering department – not recompiled from a blurry scan. Page 3 shows the complete pilot valve assembly (Part No. 708 7473) with 21 individual components, each listed with its tie rod length and nut size. When the manual says “2000 psi” next to the valve, that’s the operating pressure the part was designed for. You ignore that at your own risk.

Does This Catalog Cover the Full Machine?

This Parts Catalog focuses on the hydraulic systems – swing, traction, and attachment – which are the high-failure areas on these excavators. It does not cover the engine, electrical, or undercarriage. For those systems, you’ll need the corresponding service manual. But if you’re replacing hoses, valves, fittings, or seals in the hydraulic circuit, this is your reference. The 15 pages are dense – every page has a parts list with reference numbers, descriptions, and quantities. You also get the supersession notes that tell you if a part has been discontinued and what replacement to use. Koehring 6633L & 6638L Excavator Parts Catalog Supplement adds later revisions if your machine’s serial number falls in a certain range.

Get the Right Part the First Time

When you’re ordering parts for a 1986 Koehring, you don’t have time to cross-reference aftermarket numbers. This catalog gives you the OEM number, the description, and the exact quantity per assembly. No fluff, no reprints. If you need parts for the T-S44 or 644 models, check Koehring T-S44, 644 1974 Parts Catalog – Factory OEM Parts Reference. For context on how these machines fit into the broader industry, read Automotive Industry Overview and Automotive Industry Overview.

Can I use this catalog for later model excavators?

No. This catalog covers the 1986 production run only. Later models may have different part numbers and supersessions.

Does it include torque specs or service procedures?

This is a parts catalog, not a service manual. It lists part numbers, exploded views, and supersession information. For example, page 2 shows the attachment valve assembly with each capscrew size and quantity. You get the OEM reference, not a guess. If you need repair procedures, look for the corresponding service manual. But for ordering the right part, this is the document. The hydraulic system diagrams on page 1 and page 2 match factory assembly drawings – you can trace a leaky hose back to its exact OEM replacement without ever pulling a tape measure.

Stop losing billable hours to wrong parts and guesswork. Access the Factory Manual and keep your Koehring running on OEM spec.