Find the part number on an old trailer part

A correct quotation starts with a correct part number. Many fleets do not have the number to hand when a part fails, so this guide shows where to look on an old trailer part, what to do when the number has worn off and how to search for it once you have it.

Where the part number is usually found

Most manufacturers stamp, cast or print the number on the part itself. Look on the flat faces, on the edge of a flange, or on a label stuck to the body. A few places that work for common trailer parts:

• Axle and suspension parts. Numbers are often stamped on brackets, arms and hub covers. The axle also carries a nameplate with its type and serial number.
• Brake parts. Check the back of the brake shoe, the slack adjuster body and the face of the chamber. Our guide to trailer brake lining wear shows what else to inspect while the wheel is off.
• Valves and couplings. Look for a label on the body, and for numbers cast beside the ports.
• Fifth wheels. The model is usually on a plate near the mounting.

Clean the part with a rag first. Dirt and grease hide stamped numbers, and a torch held at a low angle makes shallow marks easier to read.

How part numbers are written

Brands format numbers in their own way. BPW numbers are written in groups of digits separated by dots, for example 03.092.27.76.0. Other makes use dashes, slashes or letters mixed with digits. Copy the number exactly as it appears, including every group, because one missing digit points to a different part.

When you type the number into the spare parts search, you do not need to match the punctuation. The search ignores dots, dashes and spaces, so you can type the digits in one run.

Common mistakes when reading a part number

A few small errors cause most wrong quotations. Check these before you send the number:

• Mixing up characters. The letter O and the digit 0, or the letter I and the digit 1, look alike on worn stamping. Compare with other numbers on the same part.
• Reading the casting number. Foundries cast their own mould numbers into a part. They are not the supplier's part number. A number that sits beside a logo is more likely the right one.
• Dropping a suffix. Many numbers end in a short group, such as a final digit or a letter. The suffix often marks a revision or a left or right hand version, so keep it.
• Copying the axle serial number. The serial number on the axle nameplate identifies the axle, not the part you need, but it helps us match the part.

If two numbers appear on the part, send both and tell us where each one was.

What to do when the number has worn off

Brake and suspension parts live in a harsh place, and numbers wear away. If you cannot read it, gather this information instead:

1. The brand and model of the trailer or truck, and the year.
2. The chassis or serial number.
3. Two or three clear photos of the part from different sides, and one of the axle nameplate.
4. The main dimensions. For a coupling, the eye or kingpin size. For a valve, the port layout and the pressure rating.

With these details our team can usually match the part. Photos of the old part next to a tape measure help a great deal.

Search first, then ask

Once you have a number, search for it on the spare parts search. If it is listed, you can add it to a quotation with one click. If it is not listed, that only means we have not handled it before. We can still source it from the principal.

You can also browse by brand on the BPW page or the trailer and truck spare parts guide, which explains which parts wear first and what we supply for each.

What to include in a quotation request

A complete request gets a faster answer. Include:

• The part number, or the photos if you have no number.
• The vehicle brand, model and year.
• The quantity.
• The delivery site.

Open the quotation form, add your parts and company details, and submit. Our sales team checks availability and replies by email with a priced quotation, lead time and payment terms. You do not need an account.