Introduction
The Master Lock No. 377KA Trailer Hitch Lock is designed to provide security for your trailer. It is compatible with 1-7/8 inch (48mm), 2 inch (51mm), and most 2-5/16 inch (59mm) trailer couplers. This lock features an advanced locking mechanism engineered to resist picking and prying, and its aluminum diecast finish offers resistance against rust and corrosion, ensuring durability in various weather conditions.
This manual provides detailed instructions for the proper setup, operation, and maintenance of your Master Lock 377KA Trailer Hitch Lock.
Package Contents
- 1 x Master Lock 377KA Trailer Hitch Lock Unit
- 2 x Keys
- 1 x Instruction Guide (this document)
Specifications
| Feature | Detail |
|---|---|
| Brand | Master Lock |
| Model Number | 377KA |
| Compatibility | 1-7/8 in. (48mm), 2 in. (51mm), and most 2-5/16 in. (59mm) trailer couplers |
| Material | Aluminum Diecast |
| Special Features | Weather Resistant, Advanced Locking Mechanism |
| Item Weight | 1.83 pounds |
| Product Dimensions | 5.6 x 4.3 x 2.8 inches |
Setup and Installation
- Prepare the Coupler: Ensure your trailer's coupler is clean and free from debris. The coupler should be in the unlocked and open position.
- Insert the Lock: Place the Master Lock 377KA unit onto the trailer coupler. The ball-shaped part of the lock should fit snugly into the coupler's receiver.
- Engage the Locking Mechanism: Push the main body of the lock towards the coupler. The internal mechanism will ratchet and secure the lock in place. You may hear clicking sounds as it tightens.
- Lock the Unit: Insert one of the provided keys into the keyhole and turn it to the locked position. Remove the key.
- Verify Security: Gently attempt to pull the lock off the coupler to ensure it is securely fastened and cannot be removed without the key.
Image: The Master Lock 377KA Trailer Hitch Lock securely installed on a trailer coupler, demonstrating its fit and position.
Image: A close-up view of the Master Lock 377KA Trailer Hitch Lock engaged with a trailer coupler, highlighting the secure connection.
Image: The Master Lock 377KA Trailer Hitch Lock, with text indicating its compatibility with 1-7/8 inch, 2 inch, and most 2-5/16 inch trailer couplers.
Operating Instructions
- Locking:
- Ensure the trailer coupler is empty and clean.
- Insert the ball portion of the lock into the coupler.
- Push the main body of the lock firmly until it ratchets into place, securing the coupler.
- Insert the key and turn to lock. Remove the key.
- Unlocking:
- Insert the correct key into the keyhole.
- Turn the key to the unlock position.
- Pull the lock unit away from the coupler to release it.
Video: Demonstration of the Master Lock 377KA Trailer Hitch Lock, showing its fit and how it secures various trailer couplers.
Maintenance
- Cleaning: Periodically clean the lock with a damp cloth to remove dirt and grime. Avoid abrasive cleaners that may damage the finish.
- Lubrication: Apply a small amount of graphite lubricant or a silicone-based spray to the keyway and internal locking mechanism annually, or more frequently in harsh environments, to ensure smooth operation and prevent corrosion.
- Inspection: Regularly inspect the lock for any signs of wear, damage, or corrosion. Ensure the locking mechanism engages properly. If any issues are found, refer to the troubleshooting section or contact customer support.
Image: The Master Lock 377KA Trailer Hitch Lock, highlighting its rust and corrosion-resistant features, which benefit from regular maintenance.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Lock is difficult to insert or remove. | Dirt or debris in the coupler or lock mechanism; lack of lubrication. | Clean the coupler and lock mechanism. Apply graphite or silicone lubricant to the keyway and moving parts. |
| Key is stiff or hard to turn. | Corrosion or dirt in the keyway. | Apply graphite lubricant to the key and keyway. Insert and remove the key several times to distribute the lubricant. |
| Lock does not fully engage or secure. | Incorrect coupler size; obstruction in the coupler. | Verify the coupler size is compatible with the lock (1-7/8", 2", or 2-5/16"). Check the coupler for any obstructions and clear them. |
Warranty and Support
The Master Lock 377KA Trailer Hitch Lock comes with a Limited Lifetime Warranty. This warranty covers defects in material and workmanship for the life of the product. For warranty claims or technical support, please visit the official Master Lock website or contact their customer service department.
For more information, visit the Master Lock Store.
