Cracked low-pressure oil or fuel lines are usually caused by vibration or defective metal. If this occurs, stop the leak by wrapping the line tightly with friction tape held in place by wire. The wire helps the tape withstand pressure and usually stops the leak until a permanent repair can be performed.
Aluminum or electrical tape may also work if the surface can be cleaned to allow adhesion.
- Clean the surface of the line and cover just the crack with a couple wraps of rubber electrical tape.
- Follow up with multiple wraps of aluminum tape.
- Wrap wire around the tube or use hose clamps over the aluminum tape to reinforce the repair.
Another quick method to repair a cracked line is with a small piece of hose.
- Use a piece of reinforced hose with an inside diameter equal to the outside diameter of the tube.
- Split the hose lengthwise.
- Coat the inside of the hose with sealant, if available.
- Install the hose over the leak with the split opposite the leak.
- Secure over the leaking area with hose clamps. Additional clamps may be added to further reinforce the repair.
Source: U.S. Army FM 4-30.31, Recovery and Battle Damage Assessment and Repair