Liftmaster BG770 Barrier Gate Parts
LiftMaster BG770 Replacement Parts
Genuine LiftMaster replacement parts for the BG770 barrier gate operator — the 1/2 HP crank-driven barrier arm operator for parking and access control lanes. Use the exploded diagram above to find the key number for the part you need, then click any part number in the table below.
Order the motor by supply voltage. Ref 26 splits three ways: K20-1050B-2P for 115/230V single phase, K20-3050B-4P for 230/460V three phase, K20-3050M-5 for 575V three phase. Read the motor data plate.
Match the overload to the motor, not the operator. Ref 27 runs 6A, 8A and 10A — a 575V three-phase machine draws far less than a 115V single-phase one.
Two rod ends, opposite threads. Ref 14 is right-hand and Ref 15 is left-hand. Both are fitted; check which end you are replacing.
Not a BG770? The larger BG790 uses a different cover, shaft, crank set and pulleys. The contactor, transformer, relays, terminal blocks and overloads are common to both.
Common BG770 Repairs
| Symptom | Usual cause | Parts to check |
|---|---|---|
| Motor runs but the arm does not move | Drive belt slipping or glazed | 16-8001 belt, K17-2001 and SW008 pulleys |
| Arm overruns or stops at the wrong angle | Limit switch or limit collar slipping | K23-2017 limit switch, K91-G0122 limit collar |
| Trips the overload repeatedly | Overload sized wrong for the motor | K25-2006, K25-2008, K25-2010 overloads |
| Operator dead, nothing at the panel | Transformer, contactor or on/off switch | K21-3260-1 transformer, K03-8024-K contactor, K23-2761 switch |
| Arm droops or has play at the hub | Arm clamp or arm hub worn | K10-8007M arm clamp, K07-8007 arm hub |
| Knocking or lost motion in the linkage | Crank set or rod ends worn | K07-8003 and K07-8004 cranks, K12-8033 / K12-8034 rod ends |
| Grinding from the drive | Gear reducer or shaft bearing | K32-8002 gear reducer, K12-8032 flanged bearing |
| Intermittent operation | Relays on the control panel | K24-24-1, K24-24-6, K24-115-1, K24-230-5 relays |
Barrier Gate Repair & Service Parts
| Ref | Part # | Description |
|---|---|---|
| 1 | K03-8024-K | Reversing Contactor |
| 2 | K07-8003 | Lower Crank |
| 3 | K80-8001 | Lock and Key Kit |
| 4 | K07-8004 | Upper Crank |
| 5 | K07-8005 | Crank Link |
| 6 | K07-8007 | Arm Hub |
| 7 | 75-32000 | Cover, BG770 |
| 8 | K10-8007M | Arm Clamp |
| 9 | K10-8014 | Switch Bracket |
| 10 | K10-18022 | Top Cover |
| 11 | 10-8017 | Access Panel |
| 12 | K11-8031 | Shaft |
| 13 | K12-8032 | Flanged Bearing, 4 Bolt, 1-1/2" |
| 14 | K12-8033 | Female Rod End, Right-Hand |
| 15 | K12-8034 | Female Rod End, Left-Hand |
| 16 | 16-8001 | Belt, 4L340 |
| 17 | K17-2001 | Pulley, 8" x 5/8", 4L Belt |
| 18 | SW008 | Reducer Pulley, 2", 5/8" Bore |
| 19 | K21-3260-1 | Transformer, 120/208/230/460, 60VA |
| 20 | K23-2017 | Limit Switch |
| 21 | K23-2761 | On/Off Switch, 125/250V, 16A |
| 22 | K23-3001 | On/Off Switch, 125/277VAC, 20A |
| 22 | K23-3005 | On/Off Switch, 125/277VAC, 20A |
| 23 | K24-24-1 | Relay, 24V, 10A |
| 24 | K24-24-6 | Relay, 3PDT, 24V, 10A |
| 25 | K32-8002 | Gear Reducer |
| 26 | K20-3050B-4P | Motor, 1/2 HP, 230/460V, 3PH, BM |
| 26 | K20-3050M-5 | Motor, 1/2 HP, 575V, 3PH, BM/CF |
| 26 | K20-1050B-2P | Motor, 1/2 HP, 115/230V, 1PH, BM |
| 27 | K25-2006 | Overload, 6A |
| 27 | K25-2008 | Overload, 8A |
| 27 | K25-2010 | Overload, 10A |
| 27 | 25-4001-5 | Relay, Overload, 1.0-1.6A — no longer available |
| 27 | 25-4002-5 | Relay, Overload, 1.6-2.5A — no longer available |
| 28 | K24-115-1 | Relay, 120V, 10A |
| 28 | K24-230-5 | Relay, 3PDT, 230V, 7A |
| 29 | K91-G0122 | Limit Collar |
| 30 | K10-8021 | Control Panel |
| 31 | 74-G0133 | Control Box — no longer available |
| 32 | K42-110-2 | Terminal Block, 10 Position |
| 33 | K42-3608 | Terminal Block, 8 Position |
| 34 | 10-8022 | E-Box Mounting Bracket — no longer available |