Description

Koehring 6633-7, 6633LC 1991 Parts Catalog

I’ve been wrenching long enough to tell the difference between a factory parts catalog and a reprint that belongs in a trash can. The Koehring 6633-7, 6633LC 1991 Parts Catalog is the real deal — 143 pages of OEM part numbers, exploded views, and serial-number-specific callouts. No blurry scans, no missing pages, no “close enough” part substitutions. If you’re maintaining a Koehring hydraulic excavator from this era, this is the reference you want on your bench.

Part Numbers and Serial Number Breakpoints

Every page in this catalog is built around the actual serial number ranges that Koehring used during production. For the 6633-7, you get range 110801 thru 110832. For the 6633LC, it’s 47000 & Up. That matters because drive devices, rollers, and track links changed between those breaks. The OCR excerpt shows it right on page 2: REF. PART NO. 731 4514 is listed as DRIVE DEVICE, TRACTION — but only for the correct serial group. A reprint would smush all years together and leave you ordering a sprocket that doesn’t fit. Check your machine’s serial plate before you touch the order form.

Why OEM Parts Catalogs Beat Aftermarket Reprints

I’ve had guys bring me a paper from some online third-party that claims to be a “factory copy.” Open it up and the part numbers don’t match, the illustrations are washed out, and the hardware callouts are missing. This 1991 Parts Catalog is a direct scan of the original Koehring document — same layout, same font, same hard data. The track shoe assembly on page 3 lists bolt and nut quantities down to the last piece: 204 bolts (part 730 5116) and 204 nuts (part 730 5103). Aftermarket reprints regularly drop those counts or guess. You don’t guess on undercarriage hardware — not if you want that shoe to stay on.

3 Critical Uses for This Catalog on the Job

First, ordering parts. Walk up to the dealer counter with the correct part number from this catalog and they won’t send you home empty-handed. Second, rebuilding subassemblies. The exploded views show how everything stacks — lower roller assemblies, track link guides, piping covers. Third, verifying used parts. When you pull a component off a salvage machine, cross-reference the part number against this catalog to confirm it’s the correct revision for your serial number.

Check Your Serial Number Before Ordering

Page 1 of the catalog has a blank line for your serial number — that’s your first step. Write it in. Then look up the applicable parts. The drive device assembly (REF 0) shows two different part numbers for the two serial groups: 731 4514 for the 6633-7 and 731 3950 for the 6633LC. Order the wrong one and the mounting bolt pattern won’t align. I’ve seen it happen. Don’t be that guy.

Lower Frame Assembly: Exploded View Data

The undercarriage section is dense. On page 2, you get the lower frame assembly with part numbers for upper rollers (731 4436-1), lower rollers (730 5333), track link guide assembly, and crawler shoe assembly. Each component lists required hardware — hardened bolts, lock washers, flat washers — with exact sizes like M20X60, M12X25, M24X100. That level of detail means you can order every nut and bolt for a full track rebuild from one source. No running to the hardware store halfway through the job.

That’s the difference between a finished job and a return trip.

Related Manuals

If you’re working on other Koehring excavators, check the Koehring 6633-5 and 6633LC Excavator Parts Catalog for the earlier model. For older Koehring machines, the Koehring T-S44, 644 1974 Parts Catalog – Factory OEM Parts Reference and Koehring S-155 1977 Parts Catalog – Factory OEM Parts Reference give you the same factory-level accuracy for those models.

For background on track system engineering, the Automotive Industry Overview provides context. And the Automotive Industry Overview is a good starting point for industry standards.

If you’re tired of guessing part numbers and returning wrong components, stop messing around with aftermarket junk. This is the file that tells you exactly what your Koehring needs. Click the button and access the factory manual.

Can I use this catalog for the 6633-5 model?

No. This catalog covers only the 6633-7 and 6633LC models.

What serial numbers are covered?

The manual lists two serial number ranges: 110801 thru 110832 for the 6633-7 and 47000 & Up for the 6633LC. Always verify your machine’s serial plate before ordering. The parts catalog uses these breakpoints to differentiate part revisions. Using the wrong serial number will get you the wrong drive device, roller, or track link. I’ve seen guys order a sprocket from a aftermarket listing only to find it doesn’t fit because the reprint ignored serial number splits. This OEM catalog has the correct breakpoints on every page.