Chamberlain HD520 Belt Drive Parts
Chamberlain HD520 Replacement Parts
The HD520 is a square rail belt drive opener — that matters, because its belt, rail, trolley and brackets are all square rail specific and will not interchange with the T-rail parts used on most LiftMaster belt drives. Everything for it is on this page: the motor unit, the belt and square rail, the safety sensors, the door hardware and the remote.
Ordering a belt? The HD520 takes the 041A5250 square rail belt, not the 41A5434 T-rail belt used on LiftMaster models. Check that your rail is square in section before ordering — the two are not interchangeable.
1. Motor Unit
First part of number below corresponds to key number above:
| Key | Part # | Description |
|---|---|---|
| 01 | 041A4371 | Belt cap retainer |
| 02 | 041A4885-5 | Gear and sprocket assembly |
| 03 | 041A7760 | End panel with light socket |
| 04 | 041C0279 | Light socket |
| 05 | 041D7572 | Light lens |
| 06 | K030B0532-1 | Capacitor |
| 08 | 041D7742-7 | Travel module |
| 09 | 041A7620-8 | Cover |
| 10 | 045ACTMC | Logic board |
| 11 | 041D7638 | End panel |
| 12 | 041A7442 | Motor with travel module |
| 13 | 041B4245-1 | Power cord, 6 ft |
| 14 | 041A3150 | Terminal block with screws |
| — | 041A7948 | Wire harness kit |
| — | 041C4253 | Wire harness kit |
The 045ACTMC logic board and the 041D7742-7 travel module are the two most commonly replaced electrical parts. If the door reverses at the wrong point or will not learn its travel, the travel module is usually the culprit rather than the board. Two wire harness kits are listed — compare against the one you are removing before ordering.
2. Belt and Square Rail
| Key | Part # | Description |
|---|---|---|
| 01 | 041A5250 | Full belt assembly — 7 ft door, square rail |
| 02 | K144C0054M | Pulley |
| 03 | 004A1008 | Master link kit |
| 04 | 041A5665 | Square rail assembly |
| 05 | 041C5141-1 | Complete trolley assembly, square rail |
| 06 | 041D0598-1 | U bracket, square rail |
| 11 | K012B0776 | Hanging bracket |
| — | 041A7276 | Wear pads |
A belt rarely fails on its own — check the pulley, trolley and wear pads while the rail is apart. Worn pads let the trolley rock in the rail and will chew a new belt. The 041A5250 is the square rail belt; if your rail is a T section, you have a different opener and need the 41A5434 family instead.
3. Safety Sensors and Brackets
| Key | Part # | Description |
|---|---|---|
| 07 | 041-0136 | Safety sensor eye kit — sending and receiving eyes, matched pair |
| 09 | 041B4494-1 | Sensor wire, white and red/white |
| — | 041-0365-000 | Sensor eyes and brackets, 1997 to current — the complete set |
| — | 041-0155-000 | Safety sensor brackets, 2021 to present |
| — | 041B0873 | Sunblocker bracket — stops sunlight false-tripping the eye |
The current 041-0136 eye kit replaces the older 41A5034 and fits Chamberlain and LiftMaster openers alike — both brands are built by the same manufacturer and share sensors.
4. Door Hardware and Installation Parts
| Key | Part # | Description |
|---|---|---|
| 01 | 041B0035B | Curved door arm |
| 02 | 041A5047-1 | Door bracket with clevis pin and fastener |
| 03 | 041A2828 | Emergency release rope and handle |
| 04 | 041A5047-2 | Header bracket with clevis pin and fastener |
| 08 | 4178B0034B | Straight door arm |
5. Remotes and Wall Controls
| Key | Part # | Description |
|---|---|---|
| 01 | 041A7185-1 | Multi-function control panel |
| — | 893MAX | 3 button visor remote — universal replacement |
| 05 | K029B0137 | Remote control visor clip |
| 10 | 10A20 | 3V CR2032 remote battery |
| — | 889LM | MyQ control panel |
The 893MAX is the universal replacement for older Chamberlain, LiftMaster and Craftsman remotes. Browse all Chamberlain remote controls.
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