Have you done any work on the lock rods recently? Someone try to jimmy your door? Try this link to a similar problem.
http://fyi.boardhost.com/viewtopic.php?id=4460

Last edited by 50vert (6/20/2016 12:25 AM)

WD-40 first... than when loosened up adjust if necessary....I put that $hip on everything...spray it good....jj

I think that was the only time I've ever been able to offer helpful advice ....... everyone else has usually beaten me to it before I get on the forum.

MS wrote:

Sounds like that round plastic piece that attaches the rod to the latch mechanism (pawl bushing which is actually NOT in this picture) may be loose.  If you are going to open up the door, plan on replacing it.  You symptoms are just like what dealt with until I replaced that part.


http://www.cjponyparts.com/scott-drake-door-latch-retainer-bushing-kit-1965-1966/p/HW1552/

Thanks for those pictures, MS.  Last nite I got the manual out and was not able to discern anything from the pictures therein.  I did get the door panel off last night and looked at the back side of the latch assembly.  I really did not know what I should be looking for but every thing had what appeared to be a substantial coating of dried out grease on it.  I sprayed everything with a lighter lubricant and will go back this morning to see if there was any effect.  Your picture will help me know what to look for.
 

Last edited by MS (6/21/2016 9:02 PM)

BobE wrote:

Although my door latch issue was not exactly the same as yours (door lock button would not move fully to the "lock" position), I removed and cleaned the entire latch assembly, lubed it up and works like new.

BobE, you hit the nail on the head.  Even though I have not finished the project yet, in combination with MS's picture of the latch assembly and a trip out to a local Mustang guy, my latch assembly was so gunked up with the wrong kind of grease that none of the moving parts would move according to the dictates of the springs, rods and buttons, etc.

I wished that I had taken a picture of it, but I didn't.  It is now soaking in a can full of paint thinner and I have scrubbed it numerous times while re-immersing it.  Tomorrow I will pull it out of its bath and give it a final blast of brake cleaner, then slather it with lubri-plate grease and check its function before reinstalling.

All of the parts, on the latch look in good shape but they could not move and interact in the manner necessary to affect the lockup of the door.
 

Last edited by boomyal (6/21/2016 11:33 PM)

Problem solved.  The door has never worked so well in the 36 years that I have owned it.  all cleaned up and lubed with white lithium grease. It was amazing how good the latch assembly looked once the caked grease was remove,  There was no sign of any wear or degradation.  That is pretty amazing for it being on the door that probably gets ten times the use of the other door.  It should be good to go for another 50 years. 

Even though the right door works fine, now that I know how to get the latch disconnected and out of the door, I may do the same to it.

BobE wrote:

boomyal - glad this worked out for you.  When I removed my assembly, it didn't look bad, but I could not see any wear or damage, and the mechanism seemed to work fine on the bench, so all that was left was to clean it up, lube a see what happens.  As I said works like new.  I also used the rattle can white grease.

Yep, Bob, it was one of those scary projects but once I was able to put an actual latch assembly in my hand, working a foot back into the dark recess was not bad at all.  Just today I noticed my right door button is very sticky when pushing it down.  Time to yank that latch out and give it the treatment.