problem with mortise cylinder getting stuck


Old 01-22-06, 05:42 PM
Thread Starter
Join Date: Jan 2006
Posts: 11
problem with mortise cylinder getting stuck

Hi, we recently moved to a 1927 home and I replaced the old Yale mortise cylinder with a new Medeco (replaced all the locks, on three doors, actually). The cylinder works fine, always, when using the thumbturn on the inside of the door--never a problem there. However, the problem arises when you use the key from the outside, as sometimes the cylinder gets stuck in that instance. It is usually when trying to lock the door--the cylinder key wont rotate far enough. You can return the cylinder to the position you started from, remove the key, and then used the thumbscrew to open and close the lock...then, you can always lock the door from the outside. Sometimes it jambs when it is in the locked position as well.
The only other thing I could add is that the thumbturn does seem pretty loose--it has a lot of play in it. Any advice would be MUCH APPRECIATED AND THANKS IN ADVANCE!!!

I would really like to repair this rather than have to consider replacing the entire mortiseset. It's nice to be using old hardware. Fingers crossed...
Sponsored Links
Old 01-22-06, 07:28 PM
Join Date: Oct 2000
Posts: 674
With a thumb turn I imagine you must have an old deadbolt lock. Typically when these jam it is related to a broken deadbolt spring. The bolt does not extend all the way and this can prevent the cylinder tailpiece from clearing since the internal parts are not quite lined up correctly.

The solution is to disassemble the lock, check for a broken spring or other parts that could be excessively worn. Many locksmiths can make a replacement spring for you if this is the case. Other parts are more problematic if replacement is needed and you would most likely have to go online to an antique hardware dealer.

A note on disassembly-these can be tricky, especially if you drop the parts before noting their location In the absense of an obvious cause, wear and tear issues can be very subtle to detect.

I am curious if it worked fine before the cylinder change? If so, this would indicate a cylinder tailpiece a bit different in size from the original or perhaps the depth the cylinder is screwed into the lock is different. A couple of turns either way can make a difference but would typically be a constant problem as opposed to your intermittant ones.

Hope this helps. Please post back with results or further questions.
Old 01-23-06, 09:58 AM
Thread Starter
Join Date: Jan 2006
Posts: 11
mortise cylinder problem continued...

Thank You!! Yes, it is a deadbolt. I am not quite sure the previous cylinder worked all the time, although, I have held on to the cylinder just in case. There is a difference in length between the old Yale cylinder and the new Medeco. I brought the old one into a locksmith and they gave me the replacment. I have tried to vary how far the cylinder is screwed into the lockset and this seems to be the only position/length that doen't completely jamb or not engage the deadbolt.

And yes, it is an intermittent issue. Like this problem. I have found, but didn't mention, that I believe the problem often arises if I turn the key in the wrong direction. So, what happens is that the key stops moving and then you turn it the other way and it just won't turn enough, stops actually, in order to engage the bolt. I don't think it is only caused by this. At any rate, as I mentioned, there is never a problem when using the thumbturn and when the lock gives me this trouble, all I have to do is open the door, turn the tumbturn twice to engage the lock to closed (bolt extended) and then to open, and then, the key works fine.

Does this make any sense as I describe it???

THANK YOU!!!!!!!!!!
Old 01-23-06, 02:20 PM
Join Date: Oct 2000
Posts: 674
It sounds like, by turning it the opposite way you may be moving some parts and they are sticking a bit causing trouble with the cylinder operation. The thumbturn when turned is resetting the parts allowing the cylinder to work.

Has this lock ever been lubricated? If not, without taking the lock apart, the first thing to do is get some lubricant (I useTriFlow brand but WD-40 is ok in a pinch) and spray a fair amount back and forth inside the lock. This is easiest to do if the cylinder is removed. The goal is to loosen up old dried up grease and any binding parts. Work all movable parts several times after lubrication.

If this does not work, or it has been lubed already, the lock should be disassembled and inspected as I mentioned before. I have seen old locks with loose or missing case screws, cracked covers, broken springs and other worn parts still kind of working. No way to tell for sure until it is removed.

Some of the old mortise locks have very few parts so if you take your time, work on a bench, set the parts out in the order you remove them, you can do it. The other option is to remove it and bring it in to see if the locksmith can find something.

This would not show binding from installation issues but it does not sound like that is your problem off hand. To check for these, one would loosen different mounting screws and check the operation each time to see if it makes a difference.
Old 01-23-06, 05:15 PM
WGW is offline
Join Date: Nov 2003
Location: Ontario
Posts: 313
If your Medeco cylinder is'nt exactly the same as the old one in length, then that could be the cause of the problem your having, but from your description I'd almost put money on it being a wrong cam (or tail piece).
Seeing that you don't know if the old Yale cylinder worked properly before the replacement, I'd suggest taking the whole lock body and cylinder in to your Locksmith and having him look it over. He'll be able to deturmine what cam is needed for this particular lock (there are several possibilities).

Old 01-24-06, 06:20 PM
Thread Starter
Join Date: Jan 2006
Posts: 11
Thank You

THANK YOU FOR THIS ADVICE. It's very kind and I appreciate it.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes