Castair Adjustable Belt Tensioner Base — 215D, 7.5-10 HP, 215 Plate Motors
The Castair 215D is the adjustable belt tensioner base — the slide plate and bracket component — for belt-drive Castair air compressors using 7.5 to 10 HP motors on a 215 frame plate. This is the base-only version. If your tensioner mechanism is still functional but the slide base is cracked, bent, or stripped, the 215D gets your compressor back in adjustment without buying a full assembly.
The adjustable design is what allows you to set and maintain proper belt tension as belts stretch over time. On a fixed motor mount, belt tension degrades with every hour of operation. An adjustable tensioner base lets you move the motor on the slide to take up belt stretch and maintain the correct tension without replacing the belt prematurely.
Part Details
- Part Number: 215D
- Type: Adjustable belt tensioner base (slide/bracket only)
- Compatible Motor Sizes: 7.5 HP and 10 HP
- Frame / Plate: 215
- Manufacturer: Cast Air (Castair)
- Price: $138.91
215D vs. 215DM — Base vs. Complete Assembly
- 215D (this part, $138.91): Tensioner base/slide only. The adjustable bracket that mounts the motor and allows slide adjustment for belt tension. Use when the base is the failed component.
- 215DM ($195.95): Complete belt tensioner assembly including tensioner mechanism and mount. Use when you need a full replacement or are building up from components.
If you are not certain which part applies to your failure, call us — we can help you identify the specific component that needs replacement on your Castair compressor model.
How Belt Tensioner Bases Work
On a belt-drive compressor, the motor mounts on a sliding base plate that can be moved away from the pump to tension the drive belt, then locked in position. As the belt stretches over time, the base slides again to compensate. The 215D provides the structural base and adjustment mechanism for this process on 215 frame motor compressors.
- Sliding adjustment: Motor position adjusts along the base to set belt tension
- Lock-down: Bolts secure the motor at the correct tension position
- Frame-specific fit: Sized specifically for 215 frame (NEMA 215T or equivalent) motors
When Does a Shop Need This Part?
- Cracked or bent slide base: Impact damage or corrosion can compromise the base plate and prevent smooth adjustment
- Stripped adjustment hardware: If the slide bolts are stripped and the motor cannot be secured at the correct tension position
- Rebuilding or upgrading a compressor: When sourcing components for a Castair compressor rebuild, using the OEM-specific tensioner base ensures correct motor alignment
- Tensioner mechanism is intact but base is failed: If the tensioner pivot/spring mechanism works but the base is the issue, the 215D is the right part — no need for the full 215DM assembly
Technical Specifications
- Part Number: 215D
- Manufacturer: Cast Air (Castair)
- Motor HP Range: 7.5 HP, 10 HP
- Motor Frame/Plate: 215
- Type: Adjustable tensioner base only
- List Price: $138.91
Note: Manufacturer product page data was not available at time of writing. Specifications are derived from the product name and part number. Contact us to confirm fit for your specific Castair compressor model before ordering.
Why Buy From Air Compressor Factory Direct?
We have specialized in air compressor parts and equipment since 2016. Castair belt tensioner components are part of our regular inventory. We can help you determine whether you need the 215D base only or the complete 215DM assembly — just give us your compressor model number when you call.
- Free shipping on qualifying orders
- Free tech support: Call 866-217-0063 to confirm the right part for your compressor
- Full manufacturer warranty
- Honest guidance: We will point you to the right part, whether it is this one or the 215DM
Call 866-217-0063 for quick answers and help!
