The Multiquip 21815 is a genuine OEM Fitting 45-Degree 12MJ x 12MO designed for STX55 and HTX44 series hydrostatic ride-on power trowels. As a direct Multiquip OEM part, it delivers the exact thread form, angle, and sealing geometry specified for these machines — no guesswork on compatibility. Part number 21815 is confirmed for STX55J6, STX55Y6, HTX44K4, HTX44K5, HTX44Y4, and HTX44Y5 models. Sourcing the correct hydraulic fitting keeps your trowel's fluid system sealed and performing at spec on every pour.
Key Features
- Genuine OEM Hydraulic Sealing Integrity — Manufactured to Multiquip's exact thread specification, ensuring the correct JIC and ORB sealing surfaces that prevent hydraulic fluid weepage under working pressure.
- 45-Degree Elbow Configuration — The angled body routes hydraulic lines cleanly around the trowel's drive components, allowing proper hose routing without sharp bends or kinking.
- Broad HTX44 and STX55 Series Coverage — Fits HTX44K4, HTX44K5, HTX44Y4, HTX44Y5, STX55J6, and STX55Y6 hydrostatic ride-on trowels from a single part number.
- Maintains Hydraulic System Pressure — A correctly seated fitting holds the circuit at operating pressure, supporting consistent blade pitch control and smooth drive response across the deck.
- Critical Fuel and Hydraulic Line Safety — A cracked, cross-threaded, or improperly rated fitting on a hydrostatic trowel can cause uncontrolled fluid loss and loss of drive — using the OEM-specified part mitigates that risk.
Hydraulic fittings like the 21815 serve as the sealed connection points between hoses, lines, and valve blocks within the trowel's hydrostatic drive and blade-pitch control circuit. A 45-degree elbow fitting routes pressurized fluid around tight clearances while maintaining a leak-free seal at both the male JIC flare end and the male ORB port end. When a fitting corrodes, cross-threads, or cracks, it allows hydraulic fluid to escape the closed circuit — causing pressure loss that directly degrades blade pitch response, forward and reverse drive, and overall machine control. Replacing a worn or damaged fitting promptly with the correct OEM part restores circuit integrity and keeps the hydraulic system operating as engineered.
For questions about part 21815 or fitment confirmation for your specific machine, contact the DHS Equipment team directly.
Part Details
| Part Number | 21815 |
|---|---|
| Brand | Multiquip |
| Part Type | Genuine OEM |
| Description | Fitting 45-Degree 12MJ x 12MO |
Compatibility & Fitment
| Name | Model |
|---|---|
| Whiteman Ride-On Power Trowels | STX55J6 |
| Whiteman Ride-On Power Trowels | HTX44K4 |
| Whiteman Ride-On Power Trowels | HTX44K5 |
| Whiteman Ride-On Power Trowels | HTX44Y4 |
| Whiteman Ride-On Power Trowels | HTX44Y5 |
| Whiteman Ride-On Power Trowels | STX55Y6 |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
