Our 2007 Fit has 36 000 km on it. The Keys work fine in the ignition set and rear hatch locks. The keys worked fine and silky smooth in the door sets when we bought the car, but with time the door lock sets have quickly become notchy and difficult. My wife is afraid to lock the doors and use the keys for fear of total failure and an expensive replacement of all keys and tumbler sets at a cost of perhaps a thousand dollars. (She doesn't leave valuables in the car and the radio is stock). The dealer said this is normal and we should expect to buy replacement door lock sets two or three times during the warantee period of the car. Of course he said that the door locks are like wiper blades or tires, expendable replaceable items. He said these are items that wear with use and are the owners responsibility to replace as they wear out. The service representative gave us a ten minute lecture on the evil of WD 40 or similar lubricants and the advantage of graphite lubricants. They did not charge us for lubricating the locks. We went to pick up the car. I put the key in the door (still stiff and notchy), pulled it out and inspected the key. Not a trace of graphite and covered with a film of fluid that smelled exactly like WD 40! Are others having a similar problem with the door locks? what are you lubricating with? How difficult is it to remove the locks and tumbler sets for proper lubrication and or replacement?

 

Didn't read past the first sentence (too much tangents), but squirt WD40 into the keyhole.

 

When i worked as a mechanic, we used 3in1. Any light oil will work fine.

 

Pb Blaster

 

This is ridiculous. I keep cars for 10+ years, and I have never had to replace ANY lock on ANY car. All you should ever use to lubricate a lock is graphite.
You can get it in little "squirt" tubes at your local auto parts store.

 

Dealers are so full of crap.

 

I have. the keys on my S10 were cheap plastic only on my key ring and they broke in less than 6 months. The replacement was a Lowes all metal that has lasted 6 years so far.
Most of the time when keys are difficult to use they have been twisted so that the backbone isn't quite sraight or flat. Vise them to true them up. If they are still difficult check to see if they are wearing out because of use or soft metal. If so you'll need new key.
see if the tip is smoothly tapered so it enters the lock easily. If it doesn't lightly oil the lock to be sure the entry 'door' slides easily when the key is pushed in.

 

Thank you for the replies. I will closely examine the key for straight flat trueness and no burrs or such which may catch on the tumblers. There is wear on the key, but not excessive. Our spare key which we never use and is new from the factory with the car, shows no wear at all, behaves about the same as the one used every day; hence my suspicion something is wearing in the tumbler set of the doors because the ignition tumblers behave perfectly normal. I have tried graphite. I suspect previous applications of other oils prevent dispersion of the graphite into the surfaces which are binding. My key should not be "crunching" it's way through the tumblers.

 

yah, there is a lot of grit and sand kickup on the rear gate so im not at all surprised if your keyhole got contaminated.

if i was you, i would even blast the keyhole with my RC car motor spray or nitro cleaner (electronic cleaner would also work) a good amount and then spray some WD40 in there after the liquid dries.

 

Sounds like you found an idiot.

 

I can't even insert my key into my passenger side door. My GD MMC bought in 2007 only has 17,000km on it. Good thing that i have keyless remote but still, i don't know why i can't insert the key.

 

Unfortunately in this time of nitwits doing damage for the fun, check that your lock actually has a full slot by using a greased straight paper clip to see if it will indeed go the full depth. If it does check your key is flat, not twisted, correct key blank, and straight. If none that all works, the dealer should fix it under warranty at 17000km (10553 miles).
If however one of your non-friends pushed something into the lock thats between you and your insurance company.
This instance we've seen here a couple of times in 50 years. Once it was 'fished' out with a strong electromagnet but the other required a new lock.