LiftMaster Q074 / K75-50130 Coupling — 3/4 × 5/8 Inch, Legacy HCT

The LiftMaster Q074 identifies coupling K75-50130 for documented legacy HCT overhead gate-operator arrangements. The HCT manufacturer parts list describes a 3/4-by-5/8-inch coupling with three pieces. Select it by the exact drive and service reference, not merely by the two listed dimensions. This is a mechanical connection component, separate from the gearbox, motor and chain-coupling release. Inspect the mating shafts, supports and alignment before choosing the repair so a new coupling is not installed onto damaged or mismatched connections.

Compatibility — Models, Versions and Exclusions

Identify the Connection Before Choosing a Coupling

A coupling connects specific mating parts, so the correct repair depends on more than the operator brand. Record the installed part number where available and photograph the connection before dismantling. Compare the shaft interfaces, axial position and retention arrangement with the applicable service drawing. Do not infer an unlisted bore or torque rating from a catalog photograph or from the size of a nearby motor.

A damaged coupling can be associated with wear, looseness, misalignment or excessive mechanical load elsewhere in the drive. Have the technician inspect the mating shafts, supports and connected mechanism before replacing it. A new coupling should not be used to hide a worn shaft connection or force a gate that binds. Correct the underlying problem and preserve the manufacturer’s intended drive geometry.

Specifications and Product Identification

Before Ordering

• Record the full HCT model and drive configuration.
• Match Q074 / K75-50130 and the 3/4 × 5/8-inch description.
• Inspect both mating shafts, supports and alignment.
• Confirm the three-piece service package and required retention hardware.

Package Contents and Separate Requirements

The HCT parts list describes Q074 as a three-piece coupling. Confirm the current K75-50130 package against the installed arrangement before service. A motor, gearbox, shaft, chain-coupling release and complete operator are not promised as included. Do not transfer the contents or dimensions of another Q-series coupling to this kit simply because the supplier names are similar.

Safety Warnings — Read Before Installation or Service

• WARNING: Removing a drive coupling may disconnect the gate from its motor or restraint. A qualified gate technician must secure the gate before service.
• Isolate AC power, batteries and other applicable supplies before working around rotating shafts or coupling components.
• Do not enlarge bores, improvise keys or use flexible components to compensate for damaged supports or excessive misalignment.
• Restore retention hardware and guards, then verify controlled movement, travel endpoints, reversal and all required protection devices before normal operation.

Related Products and Important Differences

• LMRRUL monitored photo eye — a separate protection option only where the exact operator and control revision approve it; not a universal legacy retrofit.
• LMWEKITU monitored wireless edge kit — a separate edge communication system for approved controls and resistive edges; not a replacement for this mechanical or electrical service part.

Frequently Asked Questions

What are the listed dimensions?

The manufacturer HCT parts list describes 3/4 × 5/8 inch.

How many pieces are described?

The legacy HCT parts list specifies three pieces; confirm the current package.

Is it the Q200 release?

No. Q200 is a separately identified chain-coupling release.

Will it fit later HCTDC operators?

No automatic compatibility is established; use their own parts references.

Need Help Confirming the Right Product?

Contact Garage-DoorParts.com before ordering. Send the full equipment model, readable part labels and photographs of the installed assembly. Include the dimensions, electrical configuration or accessory details relevant to your project so the listing can be checked against the actual installation.