When replacing a truck brake drum, the single most important step is identifying the correct OEM number. The wrong part not only fails to fit — it can compromise braking performance and safety.

Where to find the OEM number

• On the drum itself: most brake drums have a part number cast or etched into the rim. Clean the surface and look around the outer edge.
• In your vehicle service manual: the OEM parts list shows the exact part number for each axle position.
• From the old part's invoice or packaging: keep the original part number when ordering replacements.

Why the exact number matters

Brake drums look similar but differ in diameter, width, bolt pattern, pilot hole size and offset. A few millimeters of difference means the drum will not seat correctly or may cause vibration. Always verify the OEM number against the physical dimensions before ordering.

Common OEM numbers we supply

At UIB Truck Parts, we manufacture and supply brake drums under popular OEM numbers such as 3721AX, 3600AX, 1599009 and 05255-E (WA-69170), along with custom-machined drums to customer drawings.

Can't find your number?

Send us a photo of the old drum and its markings — our team will help you match the correct part. We reply within 24 hours.