Liftmaster 17-10363 Pulley, 1-5/8" OD, 1/2" B, 4L Belt K17-10363
The LiftMaster K17-10363 is a replacement pulley used in select LiftMaster commercial operator assemblies. It is specified as a 1-5/8 inch outside diameter pulley with a 1/2 inch bore for a 4L belt profile.
This part is commonly found in brake component diagrams rather than standard door travel hardware. It should be matched by the exact part number and dimensions because LiftMaster medium-duty operators use several pulleys that are not interchangeable.
Compatibility and Application
Deep search results and parts diagrams place K17-10363 in select LiftMaster medium-duty commercial operator brake sections. It appears in MJ medium-duty jackshaft brake service parts and is also shown in BMT-style brake component sections where the diagram key calls for the 1-5/8 inch OD, 1/2 inch bore, 4L belt pulley.
- Select LiftMaster MJ medium-duty jackshaft brake assemblies
- Select LiftMaster BMT brake component assemblies where K17-10363 is shown
- Commercial operator brake assemblies using a 1-5/8 inch OD, 1/2 inch bore, 4L belt pulley
- Medium-duty logic commercial door operator brake service applications when the parts diagram lists K17-10363
Important Fitment Notes
- Not the same as K17-10336 / 17-10336 7 inch pulley
- Not selected by belt type alone; outside diameter and bore must match
- Not a full brake assembly or solenoid kit
- Not a universal pulley for every 4L belt application
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Pulley |
| Part Number | K17-10363 |
| Outside Diameter | 1-5/8 inch |
| Bore | 1/2 inch |
| Belt Profile | 4L belt |
| Application | Select commercial operator brake / drive assemblies |
| Compatible Operator Type | Select LiftMaster medium-duty commercial operator brake assemblies |
| Notes | Match pulley dimensions and parts diagram before ordering |
Also Known As / Related Part Numbers
- K17-10363
- 17-10363
- LiftMaster 17-10363 pulley
- 1-5/8 inch OD pulley
- 1/2 inch bore 4L belt pulley
- K17-10363 pulley and disc assembly reference in some diagrams
Related Parts in the Same Operator Family
- K17-10336 - 7 inch OD pulley used in select MJ / HMJ clutch drive sections, not the same part
- K75-12494 - 120V brake solenoid kit in related brake sections
- K75-10359 - brake mounting plate in related brake sections
- 18-10716 - compression spring in related brake sections
- K31-10726 - spacer in related brake sections
Technician Notes
If a brake pulley is worn, glazed, cracked, loose, or noisy, inspect the belt and brake hardware around it. Replacing the pulley without correcting belt alignment or brake drag can cause repeat failure.
Measure the old pulley if the label is missing. A 1-5/8 inch pulley and a 7 inch pulley may both be used with 4L belts in LiftMaster commercial operator families, but they serve different locations.
Before Ordering Checklist
- Confirm the part number is K17-10363 or 17-10363
- Confirm 1-5/8 inch outside diameter
- Confirm 1/2 inch bore
- Confirm 4L belt profile
- Inspect belt wear, brake drag, and nearby hardware before reassembly
Professional Advisory
Brake and drive components should be serviced with the operator powered down and the door secured. If the brake assembly is not releasing or holding properly, have the system inspected by a qualified commercial door technician.
Product Q&A
What size is the K17-10363 pulley?
It is listed as a 1-5/8 inch outside diameter pulley with a 1/2 inch bore for a 4L belt.
Is K17-10363 the same as 17-10363?
Yes, many listings use the K prefix while the base part number is 17-10363. Match the diagram and dimensions before ordering.
Can I replace this with the larger 17-10336 pulley?
No. 17-10336 is a 7 inch pulley and is a different part used in different locations.
Where is this pulley commonly used?
It is commonly associated with select LiftMaster medium-duty commercial operator brake assemblies, including MJ and BMT brake-component references where specified.
What else should be inspected with this pulley?
Inspect the belt, brake disc, solenoid linkage, spring, spacer, and mounting hardware for wear or misalignment.
