LiftMaster K07-8007 Arm Hub for BG770 and BG790
The LiftMaster K07-8007 is an arm hub for BG770 and BG790 barrier gate operators. The arm hub is the mechanical connection point that transfers operator torque into the barrier arm assembly. It must hold the arm securely while allowing the crank linkage and drive system to move the arm through its intended travel. A worn or damaged hub can create arm wobble, poor alignment, loose mounting, or failure after impact. This part should be matched carefully because the arm hub works with the operator shaft, crank parts, arm flange, and barrier arm hardware. Correct hub fitment is especially important on high-traffic parking, commercial, and industrial barrier installations.
Compatible With
- LiftMaster BG770 and BG790 barrier gate operators where the parts diagram calls for K07-8007. Used at the barrier arm hub/flange assembly to transfer drive motion to the arm.
Compatibility should be verified by the operator model number, original part number, and replacement-parts diagram. LiftMaster barrier and commercial gate operator parts often look similar across model families but may use different shafts, collars, hubs, link geometry, or mounting hardware.
Features & Specifications
| Manufacturer | LiftMaster / Chamberlain Group |
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| Product Type | Arm hub replacement kit |
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| Part Number | K07-8007 |
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| Application | Barrier gate arm hub / flange drive connection |
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| Compatible Operator Type | LiftMaster BG770 and BG790 barrier gate operators |
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| Material / Finish | Heavy-duty metal arm hub |
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| Related Numbers | 07-8007, 078007, G078007 |
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| Notes | Inspect hub, shaft, crank link, and arm hardware after impact damage |
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Also Known As / Related Part Numbers
- K07-8007
- 07-8007
- 078007
- G078007
- LiftMaster arm hub
- BG770 arm hub
- BG790 arm hub
Technician Note
Before replacing this part, check the surrounding mechanical assembly for looseness, worn pivot points, damaged shafts, missing set screws, bent linkage, or signs of a gate or arm impact. Replacing one worn part without correcting the cause can lead to repeat failure.
Before Ordering Checklist
- Match the manufacturer part number and any older Q/G/07-series number to the original part or parts diagram.
- Confirm the operator model, series, and mechanical assembly location before ordering.
- Inspect adjacent shafts, cranks, bearings, fasteners, and linkage hardware for damage or wear.
- Do not order by appearance only; similar LiftMaster mechanical parts may not interchange.
Important Ordering Warnings
- If the barrier arm was struck, inspect the shaft, crank link, upper/lower crank, and mounting hardware before replacing only the hub.
- Do not use this hub on unrelated barrier operators unless the parts diagram lists K07-8007.
Professional Advisory
Mechanical gate and barrier operator repairs should be performed with the operator secured and power disconnected by a qualified gate technician. If the operator has impact damage, binding, unsafe movement, or high-voltage wiring exposure, have the full system inspected before returning it to service.
Product Q&A
Which operators use the K07-8007 arm hub?
K07-8007 is commonly listed for LiftMaster BG770 and BG790 barrier gate operators.
What does the arm hub do?
It transfers torque from the operator drive and linkage system to the barrier arm assembly.
Are G078007 and 07-8007 related numbers?
Yes, G078007, 078007, and 07-8007 are commonly listed as related or alternate numbers for K07-8007.
What symptoms can point to a bad arm hub?
Arm wobble, loose arm mounting, poor alignment, visible hub damage, or movement at the hub connection can point to a worn or damaged hub.
Should other parts be checked when replacing the hub?
Yes. Check the barrier arm, crank link, shaft, fasteners, and limit adjustment because hub damage often follows impact or loose hardware.
