Some of the older generation of of Onguard locks are prone to freezing up. By this I mean that they sometimes refuse to open or have trouble opening. OnGuard suggests hitting the lock with a heavy insturment when this happens.
According to the fine folks at Todson, the US distrubitor of OnGuard, the maker of the locks (Magnum in the UK) often redesigns the locks with an aim to solving this problem.
The following is from the OnGuard website.
I am having trouble opening my lock. What can I do?
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We have found that despite our efforts to make the best locks in the industry, a small number of lock owners, particularly in beachside areas and areas where salt is used to condition icy roads, encounter trouble with our lock mechanism. Corrosion and dryness of the lock cylinder sometimes cause the locking mechanim to bind 90-degrees into the rotation of the key.
There are several steps lock owners can take to prevent this. First, most of our locks come with a plastic cover to keep dirt and debris out of the locking mechanism. Keeping the cover closed at all times will greatly increase the reliable durability of the locking mechanism. Second, the locks are designed to drain water that enters the lock. As such, the water that goes through the lock can actually wash away the manufactuer's lubrication. If you feel your lock getting dry (it becomes harder and noisy to turn the key), use some light oil or lubricant to reduce friction between moving parts in the locking mechanism.
Finally, in situation where the lock does bind and users cannot get the lock open, we have discovered a technique that may help in getting the lock open to allow for further maintenance. Although we do not recommend that users rely on the following method, we have found a way to unlock most locks that are binding as a result of the above-described problem. The procedure is as follows:
1) insert the key in fully into the cylinder
2) turn it 90-degrees, right before the point where the key would normally start binding.
3) with the key in this position, sharply tap the lock with a firm object (we've used another lock, a small hammer, or similar object) along the length of the crossbar.
4) as you are tapping the lock, continue turning the key.
We should note that this method has not worked on all locks, but it has been helpful in getting users out of binds. We should also note that you should NOT FORCE THE KEY. Excessive force used to turn the key may result in bending or breaking the key or damaging the locking cylinder.
We offer the above advice and maintenace recommendations so that our consumers will have a resource to turn to when wondering how they should take care of their locks and troubleshoot them in case of an emergency. However, consumers experiencing persistent problems with the lock should contact us directly via phone (800-213-4561) or through a support ticket.
Created: 2/28/06, JCA
Modified: 4/11/06, JCA
http://www.todson.com/support/index....=viewent&id=44