Garage Door Openers · parts
LiftMaster 8557 belt, sensor, and Security+ 2.0 board parts
For exact LiftMaster model 8557, LiftMaster Canada identifies a discontinued 3/4-HP AC belt-drive opener and lists boards 045ACT and 045ACTMC, sensor kit 041A5034 with bracket kit 041A5266-3, and belt kits 041A5434-11A/13A/14A for 7/8/10-foot doors. The 045ACT page lists 8557 but marks that board discontinued; the 045ACTMC page also names 8557 and limits that replacement board to compatible models made after 2011. The 041A5034 page names 8557 but marks the sensor kit discontinued and excludes 041A4373A sensors. Confirm build date, installed sensor generation, and door height before ordering. The linked Owner’s Manual is shared with 8550; exact part fit comes from the 8557 diagram and model-specific part pages.
Safety boundary
- Use the exact 8557 Owner’s Manual for user-level operation and safety checks; verify full model and build details before ordering electrical parts.
- Do not handle internal wiring, capacitors, logic boards, motor assemblies, belt/rail service, spring or cable hardware, or door balance; use a qualified technician.
- Never bypass, disconnect, or defeat safety sensors or automatic reversal; stop automatic closing if entrapment protection is damaged or unavailable.
Compatibility requires a direct model listing, explicit supersession, or equivalent manufacturer evidence.
Models explicitly covered
These model identities have the source evidence listed below. Read the part decision and suffix limits before ordering.
Required identifiers
- Complete opener label exactly 8557; do not substitute 8550/8550W or another 3/4-HP model
- Manufacture/build information for checking the 045ACTMC board’s after-2011 condition
- Installed belt/rail and actual door height (7, 8, or 10 feet) before selecting a belt kit
- Existing sensor part label or service records to distinguish sensor generations
Compatibility rules
- LiftMaster Canada’s exact 8557 page identifies a discontinued 3/4-HP AC belt-drive opener and lists receiver boards 045ACT and 045ACTMC, sensors 041A5034 with brackets 041A5266-3, and belt kits 041A5434-11A/13A/14A for 7/8/10 feet.
- The 045ACT page lists 8557 as compatible but says the part is discontinued; it does not give a serial-specific replacement recommendation.
- The 045ACTMC page lists 8557 and limits use to compatible models manufactured after 2011. Do not infer an unconditional 045ACT-to-045ACTMC replacement for every 8557.
- The 041A5034 page lists 8557, marks the kit discontinued, and warns it is not a replacement for sensor kit 041A4373A.
- LiftMaster links an 8550/8557 Owner’s Manual; it supplies owner guidance, while the 8557 parts diagram supplies the exact-model fit list.
Never assume
- The 8557 uses the same parts as the neighboring 8550 or an 8550W wireless model.
- 045ACTMC fits every 8557 irrespective of build date; OEM states a post-2011 condition for this replacement board.
- Any sensor that visually resembles 041A5034 is interchangeable with it; LiftMaster expressly excludes 041A4373A.
- A belt length can be selected from opener horsepower alone without confirming door/rail height.
- Internal motor, capacitor, board, belt, rail, or door-hardware parts are homeowner repair instructions.
Exact 8557 model receipt
The LiftMaster Canada page displays exact model 8557 as a discontinued 3/4-HP AC belt-drive opener and lists model parts and manuals. Its diagram includes both 045ACT and 045ACTMC receiver-board entries, and 041A5034 sensor kit with bracket 041A5266-3.
Board generation and status
LiftMaster’s 045ACT page directly lists 8557 but marks that board discontinued. The separate 045ACTMC page lists 8557 for compatible models manufactured after 2011. Confirm the exact build and current part applicability with LiftMaster; this evidence does not establish a universal board supersession for every opener.
Sensors and belt length are separate checks
The OEM diagram lists the 041A5034 sensor kit and 041A5266-3 brackets. LiftMaster marks the 041A5034 kit discontinued and warns not to substitute it for 041A4373A. The diagram also lists 7-foot belt 041A5434-11A, 8-foot belt 041A5434-13A, and 10-foot belt 041A5434-14A. Verify the installed configuration and door height; no belt repair directions are provided.
Owner-safe boundary
The shared 8550/8557 Owner’s Manual is an operating/safety reference. Internal board, capacitor, motor, belt, rail, and door-hardware work belongs with a qualified service provider.