A Brief Guide to Replacing the Garage Door Carriage Assembly

Also known as a carriage, the garage door trolley is the rail between the motor and the garage door. This critical garage door part connects the door to the mechanism of the opener usually through a bar or chain that stretches across the ceiling of your garage. The operating arm, connected to the garage door trolley, provides the push or pull to raise or lower your garage door. Usually, its installed at the same time as the opener but may wear out before the opener, in which case it will need replacing.

Here’s how to replace the carriage assembly of your garage door. It’s a fairly simple DIY garage door repair if you have the right tools and equipment.

Disconnecting the Door & Carriage

Here’s a thorough step by step guide explaining disconnecting the door and carriage safely. It’s as detailed or as simple as you want it to be. You can go off of each step or read some extra details if you’re ever uncertain.

1. Disconnect the garage door’s motor from the electrical outlet.
   1. Before starting any work on the garage door opener, it is essential to disconnect the power source to prevent the risk of electric shock.
   2. Locate the power cord of the opener and unplug it from the electrical outlet.
   3. If the garage door opener is hardwired to an electric box, locate the circuit breaker that supplies power to the opener and switch it off.
   4. In the case of a wired garage door opener, it is necessary to turn off the specific breaker that controls the power supply to the opener.
2. Pull the release cord to disconnect the trolley.
   1. Locate the release cord. This is typically a red handle or cord hanging from the garage door opener assembly.
   2. Firmly grip the release cord and pull it down or toward the garage door to disengage the trolley from the opener carriage.
   3. This ensures that the opener is disengaged from the garage door and allows for manual operation.
3. Place a ladder near the end of the rail in a place you can reach the cotter pin.
   1. Put a sturdy ladder in a position near the end of the rail at the wall. This is above the garage door’s opening.
   2. Please make sure that your ladder is stable before climbing. Have a second person around to keep you steady.
4. Remove the cotter pin from the bolt.
   1. Find the cotter pin that secures the upper end of the door arm to the carriage.
   2. Use a pair of pliers to grip the pin firmly and remove it from the cotter bolt.
   3. The cotter pin is a small pin with a loop at one end that keeps the bolt in place.
5. Detach the garage door’s arm from the carriage.
   1. Once the cotter pin is out, you can now separate the door’s arm from the carriage.
   2. Be gentle while sliding the bolt out of the hole in the carriage. This will free the door’s arm.
   3. Be careful not to drop any parts or let them fall of the ladder. They can be small, easy to break and difficult to find on the floor.

Replacing the Carriage

This is much simpler than removal. Remove the bolt that connects the rail to the wall bracket. Fit the replacement carriage onto the end of the rail and reconnect the rail.

Run the garage door. This should automatically reconnect the door to the opening assembly. Congratulate yourself on a garage door repair well done.