Door Won't Unlock

[RowdyRebel]

Passenger side door won't unlock very easily. With the door open, I can lock & unlock the door just fine using either the knob on the inside or the key. However, with the door closed (or even the door open, but the jaws on the door latch closed as if the door was closed) the knob cannot be pulled up and the key sometimes turns (very difficult) but the door won't unlock. If I smack the outside of the door a few times while trying to turn the key, it will USUALLY work it's way unlocked to be able to be opened...but it just shouldn't be that difficult.

I'm not too familiar with the inner workings of these doors or the locks. What would be the most logical place to begin looking? What would potentially cause this problem?

This is why I like my Fords....even if the door is locked, you can still open it from the inside to get out, and doing so unlocks the door. Mack ain't like that...gotta unlock it first.

[MidniteMechanic]

Alot of times corrosion or dry parts will cause this. Remove the inner door trim to access the lock/latch assy and spray well with penetrating oil. Work the lock/latch while spraying to flush it out.

[joes mack]

sometimes the latch mechanism will get dried out like the other poster said and it can cause problems. the little thin piece of metal that is on the key cyl can get bent when trying to unlock it if it is hard to turn the key. like he said clean it and spray it down with penitrating oil should free it up. joe

[Mike]

Rowdy,

Before you put the door panel back on I would coat the lock and mechanism with grafite. It will stay with you for a long time and that stuff has been used by the old mechanics years ago.

mike

[Rob]

I remove the latches, place them into a pan of water and warm them to about 150 degrees or so for about fifteen minutes. This softens and allows the old grease and grit to become loose. Then swish them in fresh hot water to clean and rinse them well. After they cool, spray them well with a foaming motorcycle chain lubricant that solidifies as it dries. This will penetrate into all the nooks and crannies of the latch and will last quite some time.

I used to use diesel fuel but Momma got tired of the smell that remained in her pans, (no kidding).

I use a product from Winzer that is available online out of Texas. Stuff lasts much longer than regular motorcycle chain lube, but is expensive.

Rob