Description

Komatsu Pc55 Parts Catalog – Factory OEM 630-Page Parts Breakdown

I have seen too many seasoned mechanics lose a whole morning because they ordered the wrong hydraulic seal kit for a Komatsu Pc55. The aftermarket catalog said it fit, but the bore was off by 2 mm. That is why you need the actual factory Parts Catalog – not a reprint, not a third-party reconstruction. This is the OEM document, 630 pages, straight from Komatsu. It shows you exactly which part goes where, how it interfaces with the next assembly, and which serial number range covers your machine. No symbols you cannot decode, no missing pages.

Parts Catalog Breakdown: Reading the Symbols

On page 1, the symbol legend tells you how every item in the catalog is coded. That star symbol (☆) means the part ships as a kit rather than individually. The underline below a dashed line indicates that the parts below belong to the assembly named in the next row. If you skip reading this legend, you will order a single bolt when you should have ordered the whole bracket set. The catalog uses “G-1, G-2” for assembly numbers, “KIT” for kit groups, and “PAINT (1)” for parts shipped with primer. Every symbol matters. Take the two minutes to understand them.

Do You Need the Machine Serial Number?

Yes. Without the serial number of your Komatsu Pc55, the parts catalog is a stack of diagrams. Each figure includes a serial number column – it tells you from which machine serial onward a particular part applies. For example, a hydraulic line might be used only from machine number 5001 to 8000. Order without checking, and you get a line that does not clear the engine mount. Write down your serial number before you open the catalog. It is stamped on the machine data plate, usually on the right side of the chassis near the boom pivot.

630 Pages of Factory Part Listings

The catalog is 630 pages thick. That is not filler – every page covers a specific assembly group: engine, hydraulic pump, final drive, swing motor, undercarriage, electrical, cab. Each assembly has its own figure number. The table of contents is grouped by major machine section. If you need the track roller seal, you go to the undercarriage section, find the figure for the track frame, and read down to the roller subassembly. The quantity column tells you how many you need per assembly. If it says “AR”, that means “as required” – you order what you need, not a fixed count. Watch for that on shims and seals.

Ordering Correct Replacement Parts

When you find the part number, do not assume it still supplies. The symbol legend also covers supersessions: an arrow between two rows means the top part is superseded by the bottom one. A diamond symbol means the original part is no longer available; the replacement is listed as a kit. If you overlook that, you might end up with a back-ordered part that will never arrive. Use the catalog to check supersessions before you call your Komatsu dealer. It saves a phone call and a return trip.

Komatsu Pc55 Parts Catalog: Where to Find the Right Part Number

Every figure is numbered. The description column uses a dot system: one dot (.) means it is a component of the main assembly; two dots (..) means it is a subcomponent of that component. If you need a roller seal, you will see it under “.. ROLLER ASSEMBLY” inside the undercarriage figure. The right and left sides are marked as “DS” (right side from operator perspective) and “SN” (left side). Do not mix them – Komatsu uses handed parts for many undercarriage components. This catalog also lists optional equipment, including cold-weather packages (A for -30°C, B for -50°C).

For the hydraulic pump, the catalog groups the piston pump and gear pump separately. Each pump figure shows the valve plate, cylinder barrel, and swashplate with individual part numbers. If you are rebuilding a pump, you need this catalog to order the correct seal kit and not a generic one. Generic kits leave out the thrust washer more often than not.

If your engine is the 4D88E or 4D98E (the Pc55 typically uses a 4-cylinder diesel), the engine parts section covers the cylinder head, oil pan, injection pump, and alternator. The part numbers there match the serial number range of your machine. Check the engine serial number too – it is on a tag above the injection pump. The catalog lists both machine and engine serial ranges separately.

Wiring harnesses are shown in the electrical section. The diagrams are not the same as a service manual – they show connector shapes and wire colors in exploded form. Use them to identify a broken connector housing or a loose terminal. The catalog gives the factory part number for the entire harness, not individual pins. For pins, you need the Komatsu electrical connector catalog, but this parts catalog at least shows the harness part so you can order the correct assembly.

One more thing: this catalog includes both standard and optional equipment. The “OPTIONAL” note in the description column means the part was not standard on all machines. If your machine lacks that option, the part number is still listed for reference. Do not order it thinking it will bolt on – verify your machine’s configuration first. For example, the cold-weather coolant heater is an option; the catalog shows the heater element and bracket, but it only applies if your machine was built with that option code.

Related Manuals

• FAI Komatsu 67-80DT Parts Catalog – OEM Hydraulic Steering Piston List
• Komatsu WH609-1 WH613-1 Parts Catalog | 347 Pages OEM
• Komatsu PC14R Parts Catalog – Order Correct Parts Fast

For background on diesel engines used in the Pc55, check this Wikipedia article on diesel engines or this Wikipedia article on diesel engines.

Frequently Asked Questions

What does the “☆” symbol mean?

Kit supplied as a set rather than individually.

How do I interpret the “AR” quantity code?

“AR” stands for “as required” – you order the amount you need, not a fixed quantity. This is common for seals, shims, and other bulk items. Always check the parts catalog to confirm there is not a mandatory kit number for that particular part. Some Komatsu assemblies use a kit number even if the individual part shows AR, so cross-reference the KIT column.

Can I use this catalog for the PC55-1 or PC55-2?

The catalog covers all Komatsu Pc55 variants, but you must use the serial number column to match your specific machine. The model suffix (e.g., -1, -2) is not always listed separately; the serial number range determines applicability.

Is this a service manual or a parts catalog?

This is strictly a parts catalog – it contains exploded diagrams and part numbers. It does not include repair procedures, torque specs, or diagnostic steps. You need a separate Komatsu service manual for removal and installation instructions.

If you work on a Komatsu Pc55 and want to stop burning money on parts that do not fit, you need the factory document. Access the Factory Manual and get the correct part numbers from the 630-page OEM source. No more guessing, no more returns.