Door Lock Cylinder Fix

Discussion in 'Gen 2 Prius Technical Discussion' started by donzoh1, Jan 31, 2021.

  1. donzoh1

    donzoh1 Active Member

    Joined:
    Jan 19, 2019
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    Location:
    Lenexa, KS
    Vehicle:
    2004 Prius
    Model:
    Five
    My door has been difficult to unlock for some time with a key and the key fob doesn't work for door unlock/lock. I got 2 more keys made for the door lock cylinder and these did not work at all. My thinking was that the lock was likely gummed up which prevented the cylinder lock pins from moving freely. However, after removing the lock and thoroughly cleaning it, the key still didn't work. After taking the lock apart, I found that the pins were not properly aligned with the key inserted so that several pins were protruding and catching in the cylinder housing. What follows is my method of fixing the problem. I'm not a locksmith and this may not meet professional locksmith standards but it works.

    To remove the lock, I set the lock to unlock and removed the rubber plug in the end of the door. A Torx 30 I believe is used to undue the screw holding the lock. Fortunately, the screw is held in place when loose so don't worry about dropping it. The cylinder lock assembly is easily removed at this point. The color matching plastic lock surround can be pried off gently. You might want to take a pic or two as you go. There is a circular spring that indexes the lock in the neutral position which must be removed. After removing the circlip, the cylinder/tailpiece assembly comes out. The metal keyslot disk and flap can be gently pried off. (Putting this back later is a two person project...take my word for it.) When pulling the cylinder out, make sure the key is fully inserted. If the key is removed, several of the pins may fall out along with some very tiny springs! At this point, the key, cylinder, pins, and springs can all be submerged in a solvent and then blown out with compressed air. The problem in my case was either worn internal lock parts or a worn key. With the key inserted, all pins should be flush with the cylinder profile. Mine were not and this is why they were not turning in the lock. A grinder, rotary tool, or file will fix this. With the key in place, grind or file any protruding pins until they are flush with the outside of the cylinder. Make sure the cylinder rotates in the housing in both directions and with the key inserted either way. Again, don't remove the key at any time if the cylinder is out unless you know the pin sequence or don't mind fiddling with tiny things.
     
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  2. ChapmanF

    ChapmanF Senior Member

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    Mar 30, 2008
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    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    When you had the 2 new keys made up, did you have them cut according to the car's key code, or were they just mechanical copies of the possibly worn-out old one?

    If the problem was a worn key, and you 'fix' it this way, you may have made the lock unusable with any new key correctly cut to the car's key code in the future.
     
  3. donzoh1

    donzoh1 Active Member

    Joined:
    Jan 19, 2019
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    Location:
    Lenexa, KS
    Vehicle:
    2004 Prius
    Model:
    Five
    The keys made were mechanical copies of the old one which itself was likely a mechanical copy. Therefore, there may be generational loss of key contour, and specifically that the newer duplicates have more metal in them than a code cut key would. My theory is that if I need other copies, I can base them on the current key I have. If I want a factory key to match a code, I can pick up another lock cylinder at the junkyard for 5 bucks and get new coded keys cut to match that. However, I think a key cut from a code may actually work in the cylinder I have since I've just shaved the ends of the pins. In other words, the pins have less metal on them than they did when new so a code cut key would leave them short of the cylinder contour. In theory, other Prius keys may work as well as I've removed some key specificity but it's likely 1000's of keys would need to be tried before one would work. Again, I have no training in this area...just my ideas.
     
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