Tech & Installation


With the lock unlocked slide the frame onto your stamped steel trailer couple


Raise the black pin into the couplers ball socket


Push the key and key cylinder into the lock and turn the key to lock.

Not all couplers are the same

What is a stamped steel coupler?

Stamped steel coupler

Stamped steel couplers are formed from one piece of steel. These couplers will have a flange that flares out from the bottom of the coupler to make a lip around the base. Madlock utilizes that flange to keep your trailer safe and secure.

Cast coupler

Some couplers are made from different materials such as cast steel and have a different design. Most cast couplers do not have a flanged lip at the bottom. If you have a cast coupler Madlock will not currently fit your application.



Do you have multiple trailers?

Madlock trailer locks can also be ordered as keyed alike as a pair or multiples.