adapting a 57 mercury door latch assy

[RICH MUISE]

I recently bought a fantastic drivers side n.o.s. door latch assy on ebay that was listed with the mercury part number, but listed as 57-58 Ford/Mercury. In the listing photo it looked identical to my ford latch so I bought it. As soon as I opened the box I realized it was different and figured I'd have to resell it, but on inspection I realized that the basic unit was almost identical. The major problem being the latch gear and housing on the mercury unit protrudes further out than the fords by .160, and the lever that the outside door button actuates is lower in the housing by about 1/2". Fortunatly for ford owners this makes the mercury unit adaptable to fords, but not the other way around. I made a .160 nylon plate to fit between the latch and the door which will take care of the excess protrusion problem. next chore is to drill and tap a hole where the door button hits, I can adjust a special screw I found to the right height and tack weld it in place.It's a few hours work, but if anyone has looked for a relacement for out worn out door latch assy's you know they are imposible to find....Rich
in the photos, it should be obvious, but the old 57 latch is the one with the green ties.

[canadian_ranchero]

that is interesting.the ford parts book says they are the same

[RICH MUISE]

The box that the latch assembly came in was mercury products division. Number on the box was LMS527A. As with our ford latches, there are no part no's stamped on the unit so I guess there is no way of knowing for sure that the box was original to that latch. A lot of stuff can happen over 50+ years. The guy I bought it from had bought it for a 57 ford, but didn't realize it could be adapted so he resold it. Interesting the ford manual lists them as the same...In general, do identical parts share the same part number whether used on Ford or Mercury, or do they have their own numbers?

[Lou]

In most of the cases I've found parts that are identical and fit Ford and Mercury and /or other FoMoCo Cars will have a Ford Part Number. The exception seems to be accessories such as radios, antennas, spot lights, outside mirrors, etc.

[RICH MUISE]

OK...a year later and a final update. I've been finally getting to assemble some of the new stuff on my car now that it has paint..I started with the driver's side door because I was anxious to get a final word on whether or not the '57 Mercury N.O.S. latch was going to work with the mods I made as explained above. The mods I made worked great..
The .16 nylon spacer plate put the starwheel at the right protrusion from the door
The hex bolt made the door button work the latch as it should

the inside door handle crank rod worked without alterations to unlatch the door

HOWEVER (they always seem to come up)....I had to do one more alteration to make the door lock button rod and the key lock cylinder rod function. Both of these come off the same tab and it was in a different location on the merc latch than the original. I could have used the merc tab location for the button lock, but it wouldn't have worked for the key cylinder. To resolve the problem I cut the needed tab off my old passenger side latch, flipped it over, and welded it to the merc latch. Now everything works, and is installed. The circled tab in the photo is the one I welded on, and the one with the X will not be used.
A lot of work, but the NOS drivers latches are soooo hard to find.
Now that that's installed I can move on to getting the electric windows and new glass finished up.....I just love this new stuff!  Rich