The Multiquip 50311 Lock Nut is a genuine OEM fastener used across a wide range of Multiquip, Whiteman, and Essick equipment, including concrete pumps, mortar and concrete mixers, power buggies, rollers, and trash pumps. As a direct OEM replacement, part 50311 meets the original design specifications for the fastener positions it serves across models such as LS300GK, WM70, AR13D, WBH-16, and EM120. With fitment spanning dozens of machine families, verifying this part number against your equipment model before ordering is always recommended — and 50311 makes that straightforward. DHS Equipment supplies this part as a genuine Multiquip OEM component, so you can order with confidence.
Key Features
- Genuine OEM Fastener Grade — Manufactured to the original torque retention and thread specification required for the fastener positions on each compatible machine, not a generic hardware substitute.
- Drop-In Replacement — Matches the original thread pitch, dimension, and locking profile, so installation follows the same procedure as the factory-installed hardware.
- Broad Multiquip Family Fitment — Confirmed for concrete pumps (LS300GK, LS400, LS500, LS600), Whiteman and Essick mixers (WM70, WM90, EM70, EM90, EM120, PRO12), power buggies (WBH-16, WBH-21, WTB-16), rollers (AR13, AR14, RW1404, V304, V305), and trash pumps (MQ600TD80 series).
- Locking Retention Under Vibration — The locking feature resists loosening caused by the vibration and cyclic loading common to compaction, mixing, and pumping equipment — preventing fastener migration during operation.
- Sourced Direct from Multiquip — Supplied as a genuine OEM part through DHS Equipment, ensuring the correct part number 50311 is fulfilled exactly as specified by Multiquip.
A lock nut is a fastener designed to resist loosening under vibration, shock loads, and dynamic stress — conditions that are common across construction equipment in active use. Unlike a standard nut, the locking mechanism (whether a nylon insert, prevailing torque profile, or deformed thread) maintains clamping force even as the machine cycles through normal operation. When a lock nut backs off or fails, the joint it secures can shift, create play, or cause secondary component damage — making timely replacement with the correct OEM-spec fastener essential to maintaining structural integrity across the assembly.
Part Details
| Part Number | 50311 |
|---|---|
| Brand | Multiquip |
| Part Type | Genuine OEM |
| Description | Lock Nut |
Compatibility & Fitment
| Name | Model |
|---|---|
| Mayco Pumps | LS300GK |
| Essick Mixers | EM120 |
| Essick Mixers | EM120P Series |
| Essick Mixers | EM120S Series |
| Essick Mixers | EM70P/S |
| Essick Mixers | EM70SLF |
| Essick Mixers | EM90P/S |
| Essick Mixers | EM90SLF |
| Essick Mixers | PRO12 |
| Essick Mixers | PRO12E51 |
| Essick Mixers | PRO12E53 |
| Mayco Pumps | C30HDGA |
| Mayco Pumps | LS300G |
| Mayco Pumps | LS300P |
| Mayco Pumps | LS400 |
| Mayco Pumps | LS40D |
| Mayco Pumps | LS40TD |
| Mayco Pumps | LS500 |
| Mayco Pumps | LS50TD |
| Mayco Pumps | LS600 |
| Mayco Pumps | LS600P |
| Mayco Pumps | LS60TD |
| Power Buggies | WBH-16 |
| Power Buggies | WBH-16E |
| Power Buggies | WBH-16EAWD |
| Power Buggies | WBH-16EAWDF |
| Power Buggies | WBH-16EF |
| Power Buggies | WBH-16F |
| Power Buggies | WBH-21EF |
| Power Buggies | WBH-21EFP |
| Power Buggies | WBH21EPA |
| Power Buggies | WTB-16 |
| Power Buggies | WTB-16PD |
| Rollers | AR13D |
| Rollers | AR13H |
| Rollers | AR13HA/HAR |
| Rollers | AR13HC |
| Rollers | AR14H |
| Rollers | RW1404 |
| Rollers | RW1404MR |
| Rollers | RW1404MR S/N 326075 and up |
| Rollers | RW1504HF up to S/N 1534188 |
| Rollers | RW3010 |
| Rollers | V304EH |
| Rollers | V304ER |
| Rollers | V304EY |
| Rollers | V305EH |
| Rollers | V305EK |
| Trash Pumps | MQ600TD80-TLRB |
| Trash Pumps | MQ600TD80-TLRP |
| Whiteman Mixers | WM120PH |
| Whiteman Mixers | WM120SH |
| Whiteman Mixers | WM63E |
| Whiteman Mixers | WM63H5 |
| Whiteman Mixers | WM63H8 |
| Whiteman Mixers | WM70PLF |
| Whiteman Mixers | WM70S/P |
| Whiteman Mixers | WM70SLF |
| Whiteman Mixers | WM90PLF |
| Whiteman Mixers | WM90S/P |
| Whiteman Mixers | WM90SLF |
| Whiteman Mixers | WM63SLF |
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.
