A few days ago the key to the front door started to malfunction. I used a spray from the store to clean it up. At first it seemed to improve things but later the lock became completely stuck. I also used WD-40 to clean the lock to no avail.

What do you recommend using? I heard about graphite powder. Is it any good?

Just to give a bit of context. The lock is a "Vachette" one (I'm in France). It seems a good brand, but the lock seems old (I'm in a rented appartment).

I was able to open the cylinder while cleaning it. Lots of greyish stuff came out. I guess it was the graphite. The fact that the lock seized completely after using wd40 makes me think that re-adding graphite could improve the situation.

Update: I added graphite and the lock moves better than ever now. Looks like wd40 washed away all the graphite and completely seized the lock. Adding graphite and moving the lock back and forth solved the problem (for now...)

  • 2
    Graphite powder should have been your first choice. Adding right now will probably gum the lock up more. Wait for the lock to "dry out" a bit.
    – JACK
    Commented Nov 15, 2023 at 18:25
  • Graphite powder might help some. It is used since it does not collect dirt as much. I have a feeling that you might need to take it part to clean and/or see if any parts are worn. Could it be ice in the lock?
    – crip659
    Commented Nov 15, 2023 at 18:26
  • 2
    If the WD40 didn't work, try duct tape :) Seriously WD40 is the wrong stuff for that. Honestly, it's the wrong stuff for just about every application it's put to, and destroys plastic parts over time. Yes, you need the lock graphite type stuff, it's either a powder or "powder in solvent" in a spray can, and the solvent fully evaporates. Commented Nov 15, 2023 at 18:45
  • From your description I get the impression that lubrication isn't a solution. If you've cleaned it and lubed it it should work for years, even with a lube which isn't ideal. I think you have worn parts. Please revise to tell us more about your hardware. You've been quite vague so far.
    – isherwood
    Commented Nov 15, 2023 at 19:46
  • 2
    If you are renting the landlord should be responsible for the front door lock.
    – Barry
    Commented Nov 15, 2023 at 23:03

3 Answers 3


As Ecnerwal says when it begins to seize like this, it's time for a new one.

According to French law, lock maintenance is the tenant's responsibility, but if it fails due to wear and tear (ie, old age) then it's the landlord's responsibility.

In other words, you should call the landlord and ask them to replace the lock.

If you replace the lock yourself, make sure to keep the old one as evidence it failed due to wear and tear (ie, you didn't break it). If your landlord is honest they should agree to pay for it. Of course you need to give them the keys to the new lock when you leave.

If it's a lock like this:

enter image description here

then you will probably have to change it, in this case the problem is to find one that fits. Make sure you measure the dimensions highlighted with blue arrows:

enter image description here

If it's a high security lock like this one:

enter image description here

Then most likely you can find spare parts. Google the brand and model + "cylindre" to get this:

enter image description here

It is much cheaper and easier to just change the lock cylinder than the whole thing.


A new lock.

A lock which has started to malfunction is likely worn past the point of "lube it up and call it a day" and non-working front door locks tend to have expensive and inconvenient side effects.

Replacing the whole lock is very likely going to cost less than having a locksmith service the one you have (unless you have a locksmith do the replacing, and possibly even then, since it's also less labor even with markup on the lock.)

If you're particularly attached to the existing lock, a new lock (for a few days/weeks) would allow you to drop the old lock off with a locksmith for rebuilding, without the "out of shop service call" markup. Or to have a try at rebuilding it yourself, if you are so inclined.

  • 3
    I would say that depends on the quality of the lock. If you bought it at Home Depot, yes. But any of my Medeco or Schlage kit is going back to the locksmith for a looksy. Also the trick to doing business with locksmiths is to remove your door hardware from the door (substitute any crap) and walk it into their physical shop. #1 that protects you from fly by night/fake/lead generator locksmiths found on the internet, #2 the locksmith never knows your address, and #3 it's dirt cheap, I often get out of my locksmith for under $30 for a service item like that. Commented Nov 15, 2023 at 18:50
  • 3
    Funny thing about high-quality locks - they rarely fail in the first place ;^)
    – Ecnerwal
    Commented Nov 15, 2023 at 18:52
  • Well, it is a quality lock, but it is really old, I guess. I will try graphite, then locksmith then a new one, if everything else fails. Commented Nov 15, 2023 at 19:00
  • Seriously, jut swap the lock (shouldn't need to be an overly fancy one, as it should only be a few days or weeks) so you can take the one you want fixed to the locksmith.
    – Ecnerwal
    Commented Nov 15, 2023 at 19:37
  • The hard part is finding a locksmith who actually has a shop as opposed to the back of a van. I'm in a city of 1,000,000+ and there are only a couple.
    – FreeMan
    Commented Nov 15, 2023 at 19:40

Really depends on what has "siezed" and why.

Graphite (used sparingly, all it takes is a puff/dusting) was a traditional lubricant for locks. A better choice these days is something like Tri-Flow (one of several equivalents) which has a wet carrier that evaporates, leaving behind a dusting of microspheres -- tiny ball bearings. WD40 provokes religious arguments, but at least is generally harmless, and like the liquid in the microspheres lubes may act as a solvent to loosen things up.

Or, in winter, the lock cylinder may have gotten wet and frozen. Lock de-icer (basically alcohol) does work to loosen that, or you can try heating the key.

But there's a lot more that can cause problems, from loosened or overtightened screws to mechanical wear to weakening springs to... If you don't have the skills and/or patience, replacing it is a reasonable choice. If you actually care about security, as opposed to just wanting privacy, I would recommend a Grade 2 lock, which is a step up from the Grade 3 most builders install because it's cheap. Basic lock security depends on design, materials, and precision of manufacturing; Grade 2 improves all of these over Grade 3. (And on installation and use, of course!) Grade 3 is cheap enough to be considered disposable, even if it can be repaired.

If it's already a good quality lock, and simple fixes like dismounting and remounting it don't resolve it, then I'd suggest you can take it to a locksmith to avoid the trip charge... if you can find a locksmith who still has a shop. If course that's a bit of a gamble; if the problem is how it was installed he'd have to look at your door, so you might waste a bit of time and a bit of money and wind up paying the on-site fee anyway. But it's worth considering.

(ORK Security Services, a division of Kubyc Solutions. Full-service locksmithing, extremely part-time; basically just helping friends. Haven't even renewed my bond, or my trade-journal subscription, in a long time.... Migawd, I've retired from a hobby.)


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