The Castair B32 is a replacement V-belt for Cast Air air compressor drive systems. The B-section designation identifies this as a standard B-profile industrial V-belt — 21/32 inch top width, 13/32 inch depth. The 32 designation indicates the belt pitch length in inches. This belt drives the compressor pump from the motor pulley and is a normal wear item that requires replacement on a maintenance schedule or when wear signs appear.
Cast Air's industrial compressor lineup uses B-section V-belts throughout the C1, C2, C3, and C4 pump families. The specific belt length varies by pump size, HP rating, and pulley configuration. Ordering the correct length belt for your specific compressor model is critical — an undersized belt will not reach the pulleys, and an oversized belt will not maintain proper tension.
Belt Identification
- Section: B (21/32" top width x 13/32" depth)
- Pitch Length: 32 inches
- Type: Standard industrial V-belt
- Application: Air compressor drive — motor pulley to pump flywheel/sheave
When to Replace the Belt
- Cracking or checking visible along the sidewalls or underside
- Glazed (shiny) belt surface — indicates slippage, reduces drive efficiency
- Belt has stretched beyond the motor mount adjustment range
- Squealing at startup or under load
- Visible fraying, chunking, or material separation
- Routine replacement at the manufacturer's recommended interval (check your compressor manual for hour-based interval)
Installation
Depressurize the compressor and lock out the electrical disconnect before replacing the belt. Slide the motor mount to release tension, remove the old belt, route the new belt over both pulleys, and set tension so the belt deflects approximately 1/2 inch under moderate finger pressure at the center of the span. Tighten the motor mount fasteners and recheck tension after the first operating session — new belts seat slightly during break-in and may need a minor tension adjustment.
If your compressor uses matched belt pairs (some C3 and C4 configurations), replace both belts simultaneously. Mixing a new belt with an old stretched one causes uneven load sharing and accelerates wear on both.
Compatibility
The B32 is in the mid-length range for B-section compressor drive belts. Fits Cast Air models that specify this belt length — confirm against your unit's parts diagram or the motor mount label. Call 866-217-0063 or Cast Air at (320) 796-0851.
What is in the Box
- One replacement V-belt, B32 specification
Why Buy From OEM Diagnostic Tools?
We have specialized in professional shop equipment since 2016. Free shipping on all parts orders, free pre-sale technical support at 866-217-0063, and Cast Air manufacturer warranty. Call us with your compressor model and serial number and we will confirm the correct belt specification before you order. Getting the wrong belt length is a frustrating delay — call first.
Call 866-217-0063 for quick answers and help!
