Description

Kyokuto Kaihatsu PY21-50 Parts Catalog

I’ve been wrenching for 28 years, and I can tell you the difference between a job that goes smooth and one that ends with a truck down for a week is parts ordering. You get the wrong piston, wrong seal, wrong hose – you’re stuck. So when I saw this Kyokuto Kaihatsu PY21-50 Parts Catalog, I knew it belonged on the bench of anyone who touches these concrete pumps. It’s 240 pages of factory part numbers, exploded diagrams, and the exact codes you need to order genuine components. No aftermarket guesswork. No calling the dealer three times.

This catalog is published by Kyokuto Kaihatsu themselves. That means the part numbers printed on the pages are the ones they stamped on the original components. You cross-reference that with the Automotive Industry Overview of construction equipment standards – but the real authority is the OEM document. Every digit matters. Page 2 of the catalog shows the exact format you need to use when ordering: catalog number, main part number, code, part number, name, size, quantity. Screw that up and you get the wrong part.

240 Pages of Factory Part Numbers

That’s not filler. Page 3 alone gives you the main parts diagram – the “主要品目図” – showing every major assembly on the PY21-50 with reference numbers. Flipping through, you’ll find the boom sections, the piston assembly, the concrete pump body, the hydraulic components. Each part has a unique Kyokuto Kaihatsu part number. If you’ve ever tried to match an aftermarket part to a worn-out piece without a number, you know the pain. This catalog stops that.

Main Parts Diagram – What Page 3 Tells You

Page 3 is the first exploded view. It shows the entire 29m long boom, the three-section folding boom, the piston, the control valves. The diagram uses reference numbers that link to the parts table on the following pages. I’ve seen too many guys order a “piston” without the part number and end up with one that doesn’t fit the PY21-50. This catalog gives you the number – VE32-M0012 for the piston, for example. You confirm the size, the quantity (one per unit), and you order. Done.

How to Order Parts the Right Way

Page 2 of the catalog spells out the ordering procedure. You need the product name (コンクリートポンプ車), the chassis model (PY21-50), the serial number (製造NO.), and the chassis frame number (シャシ型式). Then you write down the part number from the catalog. Do that once, and your part arrives correct. Skip it, and you’re waiting another week. This isn’t a guess – it’s a system. Treat it like a torque sequence: follow the steps.

OEM vs Aftermarket: The Real Difference

Aftermarket parts catalogs often reprint numbers with typos or group parts by “universal fit.” That’s how you get a seal that’s 0.5 mm off and blows out at 500 psi. Kyokuto Kaihatsu’s own catalog is the source. Every part listed here was designed, tested, and numbered by the same people who built the truck. The 240 pages were compiled from the engineering drawings. You cannot get more accurate than that. If you’re working on a PY21-50, this is the only parts list you trust. For earlier models, check the Kyokuto PH11-50 1987 Parts Catalog or the Kyokuto PY120-36 Parts Catalog – those are also factory documents. But for this specific 29m boom concrete pump, the PY21-50 catalog is your bible.

Does This Catalog Cover the PY21-50 Concrete Pump?

Yes. It’s specifically for the 29m long boom (3‑section folding) concrete pump truck mounted on a 10‑ton chassis, model PY21-50. If you have the PY21-51A variant, use Kyokuto PY21-51A Concrete Pump Parts Catalog – that’s a separate document because the boom articulation changed. This one covers the PY21-50 only. Check the chassis plate, match the model number, and you’re set.

What about the hydraulic pump – is that listed?

Yes. The pump, valves, and seals appear in the section for the hydraulic system. You’ll need the page number from the table of contents (not provided in the source data, but the catalog is fully searchable if you get the PDF).

I need the part number for the boom cylinder pin. Where do I find it?

Start at the main parts diagram on page 3. Find the reference number for the boom section (e.g., items 25-34 in the diagram). Then go to the main parts list table (pages starting after page 3) to match that number with the Kyokuto Kaihatsu part number. The pin will be listed under the boom assembly. If you don’t see it, check the cylinder subassembly section. The catalog organizes by assembly group. Take a picture of the old pin, note any markings, and cross-reference. If you still can’t find it, call the dealer with the chassis serial number – but 90% of the time the part number is in this catalog. Automotive Industry Overview [LINK_ID_EXT_1] of heavy equipment parts logistics confirms that OEM catalogs are the only reliable source for wear items.

Now, if you’re serious about keeping that concrete pump running without chasing parts for two weeks, you want the original factory document on your hard drive – or better, printed and hung in the shop. Access the Factory Manual and get the part numbers you need before you break the next bolt.