Swing Gate SW425 parts
LiftMaster SW425 Swing Gate Operator Parts
Genuine replacement parts for the LiftMaster SW425 12 volt DC swing gate operator. Use the illustrated parts drawing above with the tables below, then click any part number to order. Lettered callouts are service kits; numbered callouts are individual parts.
Before you order — three things to check.
1. The SW425 shares most of its electrics with the SL505 slide operator, but not its mechanics. Both are 12V DC units and use the same rectifier, board guard, resistor, transformer, overload, alarm, charger, batteries and control board. The arm assembly, drive shaft, motor and limit switch are specific to this swing operator. If a part looks familiar from an SL505, it probably is — but confirm before ordering.
2. Two solar and cover kits differ from the SL505 by a single digit and are not interchangeable. The SW425 takes solar kit K74-40031 and cover kit K74-40141. The SL505 takes K74-40032 and K74-40041. Check the number carefully.
3. There are two control boards. K79-40056 is the full system board and K79-40098 is the solar board. Identify which is fitted before ordering — they are not interchangeable.
Part numbers shown as plain text rather than links are no longer available from the manufacturer. They are listed so you can identify what you have.
Common SW425 Repairs
| Symptom | Usual cause | Parts to check |
|---|---|---|
| Gate slow, weak, or quits mid-cycle | Batteries at end of life | 29-NP712 (takes two), 29-40095 charger |
| Batteries never reach full charge | Charger or bridge rectifier | 29-40095, Rectifier Kit K74-40084, 21-40074 transformer |
| Motor breaker trips on every cycle | Breaker, overload, or a binding gate | 25-40152, 25-40083, 29-40071 resistor |
| Gate overruns or will not stop at limit | Limit switch or limit collar | 23-40161, 13-10465, Limit Kit K74-40151 |
| Arm loose, bent, or sagging | Arm assembly worn | Arm Kit K75-40132, 10-40137 gate bracket |
| Grinding or play in the drive | Drive shaft or motor reducer | Drive Shaft Kit K72-40146, Motor Reducer Kit K75-40147 |
| Operator dead, no response | Control board | K79-40056 full system or K79-40098 solar |
Service Kits
| Ref | Part # | Description |
|---|---|---|
| A | K75-40147 | Motor Reducer Assembly — gear set, motor mount bracket, bearing plate, flange bearing, 12VDC motor, 7 amp motor breaker and hardware |
| B | K74-40084 | Bridge Rectifier Assembly — cap rectifier, bridge rectifier and hardware |
| C | K74-40045 | Control Board Guard and Standoff Kit — guard, jumpers, standoffs and screws |
| D | K74-40065 | External Resistor Service Kit — external current resistor, shrink wrap and wiring |
| E | K72-40146 | Drive Shaft Assembly — drive shaft, gear set, friction plate, pillow block bearings, set screw collars and hardware |
| F | K74-40141 | Operator Cover Service Kit — cover, label, socket screw and washers |
| G | K74-40031 | Solar Panel Service Kit — solar bracket, panel, modular connectors and hardware |
| H | K74-40151 | Limit Switch Service Kit — SPDT limit switches, standoffs, screws and washers |
| I | K75-40132 | Primary and Secondary Arm Service Kit — outer and inner primary arm, swivel, galvanized coupling and hardware, no longer available |
Individual Parts
| Ref | Part # | Description |
|---|---|---|
| 1 | 10-40137 | Gate Bracket |
| 2 | 20-40155 | Motor, 12V DC |
| 3 | 21-40074 | Transformer, 120V 60Hz — no longer available |
| 4 | 23-40161 | Limit Switch, SPDT |
| 5 | 25-40083 | Overload, 1.5 Amp (supplied as K25-40083) |
| 6 | 29-40071 | Resistor, 1 Ohm, 25W |
| 7 | 29-40089 | Sonalert Piezo Alarm |
| 8 | 29-40095 | Battery Charger, 12V .5A Dual Stage |
| 9 | 29-NP712 | Battery, 12V 7AH (Qty 2) |
| 10 | K79-40056 | Control Board, Full System |
| 11 | 25-40152 | Motor Breaker, 7 Amp |
Parts Not Shown
| Ref | Part # | Description |
|---|---|---|
| — | K79-40098 | Control Board, Solar |
| — | 13-10465 | Limit Collar |
See also the SL505 slide gate parts page — same 12V DC platform — or the full LiftMaster gate operator parts catalog.