Description

O&K 5500Z L55 1991 Parts Catalog – Factory TB125 Manual

Ever ordered a hydraulic filter only to get something that didn’t fit? That’s what happens when you rely on aftermarket cross-references or guess from a photo. This O&K 5500Z, L55 1991 Parts Catalog is the factory-issued document – 356 pages of part numbers, item callouts, and grouping that lets you find exactly what you need before you ever call the dealer. I’ve wasted hours chasing wrong parts because someone grabbed a number off a worn-out sticker. This manual ends that.

Parts Group Numbering System – How It Works

O&K splits the machine into group numbers. The first two digits tell you the system – 32 for Hydraulic System, 05 for Hydraulic Tank Assembly, then 01 for the filter inside. That’s the kind of logic that makes sense when you’re standing under a loader in a San Antonio lot with a busted O-ring. Page 3 of the manual explains this exactly: “Example: Group 32 05 01 – 32 indicates Hydraulic System, 05 indicates Hydraulic Tank Assembly, 01 indicates Hydraulic Filter.” You don’t need to flip through the whole book blind.

What the Index Tells You

The front index is your first stop. Find the basic system (Engine, Transmission, Hydraulics, etc.) and it points you to the right illustration page. Each illustration has numbered callouts that match the parts list below. That list gives you the part number, the name, and sometimes quantity per assembly. No guesswork. You see a worn-out seal on the lift cylinder? Look up the group for hydraulic cylinders, find the illustration, and order the exact seal kit. I’ve done it for three loaders this year alone.

7 Main System Groups Covered

Without a full extracted TOC I can’t name every chapter, but the OCR shows groups covering engine, transmission, axles, hydraulic system, electrical, frame, and attachments. The group numbers run from 01 (Engine) up through 90 (Miscellaneous). Each group is broken into subgroups for specific assemblies. That’s the kind of structure that saves a half-hour hunt during a Saturday rebuild. You need charge pressure parts? Look for group 32. Need steering cylinder rebuild kit? Group 29. It’s all there.

Ordering Parts: What You Must Include

Page 4 spells it out: machine model number, machine serial number, part number, part name, quantity, and shipping address. Miss the serial number and you risk getting a part meant for a different revision. The manual even has blanks on page 2 for you to write down your machine’s serials – engine, transmission, front axle, rear axle. Fill those in the day the manual arrives. I’ve seen shops waste three weeks chasing a wrong axle shaft because someone skipped the serial check.

Why OEM Parts Catalog Beats Aftermarket

Aftermarket part catalogs are copied from someone’s old copy, often missing revision updates. This is the actual factory print – Revision 3, August 1991 from O&K Trojan Inc. The manual says: “Use only parts which are authorized by O&K Trojan Industries to ensure that original dependability and performance will be maintained.” That isn’t marketing fluff – it’s a liability statement. Factory part numbers are tested. Third-party numbers change without notice and might be superseded by a different design. Stick with OEM documentation and you avoid the “that should fit” gamble.

Frequently Asked Questions

Does this manual cover repair procedures or only parts?

It’s a parts catalog, not a service manual. It shows exploded diagrams and part numbers so you order the correct components. For repair steps you’d need the corresponding service manual.

Can I use the part numbers from this catalog to order from any dealer?

Yes. O&K dealers use these same numbers. Keep your machine serial number handy because some parts are serial number–specific. The manual won’t help if you ignore that.

How do I find a part if I don’t know the group number?

Use the index. Flip to the front of the manual, look up the system (e.g., “Transmission”), then follow the page reference to the illustration. If you still can’t find it, the book has a numerical part number index at the back – find a number you know and it will point you to the illustration.

Is this the same as the manual on CD or access sites?

AutoRepairManuals sells authentic OEM scans from the original paper manual. Many access sites sell poor-quality copies or incomplete versions. This is the full 356-page factory PDF.

Related Manuals You Might Need

• O&K 5500Z L55 1991 Parts Catalog – Factory TB125
• O&K L45, 4500Z 1990 Parts Catalog – Parts Manual TB126
• O&K L3000 Parts Catalog – Factory OEM Manual (236 Pages)

For background on how heavy equipment documentation standards fit into the broader Automotive Industry Overview, note that O&K used the same group-numbering philosophy common in construction equipment. This manual follows that tradition precisely. Automotive Industry Overview

If you’re working on an older 5500Z or L55 loader, having this catalog on your tablet or printed out means you stop guessing and start ordering the right part the first call. Access the Factory Manual now and keep your shop running without the parts-dealer runaround.