Sliding Lock For Passenger Door

[Superhart]

I decided to attempt to modify a passenger side latch on my 1930 Model A coupe to accommodate a sliding lock mechanism. First, I placed an order with Snyder’s for a new set of latches along with a sliding lock, lock knob mounting screws and escutcheon. When the parts arrived it appeared that this might not be such a complicated modification after all. Look at the first photo and you will note the basic differences between the driver (left) and passenger (right) latches. The backing plates are already stamped the same providing the trough that the lock bar slides in. On the left hinge the lock bar slides in a trough and is held in place by a small retainer that is tack welded in place. The bar is spring loaded. The spring is difficult to see in the photo because it is wrapped around the small post shown and is hidden by the latch spring. When you slide the sliding lock button on your door, the lock presses against the lock bar mounted on the latch and pushes it into alignment with a pawl preventing the door handle from opening the latch. Very simple yet quite effective.




The first thing to do was to cannibalize the left latch to obtain the parts I needed to mount on the right hinge. I began by carefully drilling through the tack welds on the lock bar retainer until it popped free. Then I turned the backing plate over and noted that the small slotted post I needed was peened in place like a rivet so I carefully drilled until I was able to extract the post from its mounting hole.



Using the cannibalized left latch as a guide I located the mounting hole for the slotted post and used a #11 drill bit to drill the hole which was a good press fit for the post. On the exterior surface of the right latch I slightly beveled the edge of the mounting hole to provide a little more room for the weld needed to secure the post.





See the photo below of the four parts removed from the left latch needed to install on the right latch.



Next, I installed the slotted post in the drilled hole in the right latch and tack welded it in place from the opposite side.



Finally I will place the lock bar in the trough and tack weld the retainer. The lock bar spring will be installed to complete the modification. I will post the final photos when available.

I decided to leave the left door sliding lock operational so, if needed, I could lock both doors while driving. Yes, I realize there is a possibility of locking myself out of the car and having to break a window to get in but I will take that chance. I will post further photos and text as the project progresses. I now need to remove the right door interior trim panel, mount the sliding lock mechanism, cut an access hole in the rim panel and install the escutcheon. I hope that this narrative and photos will prove helpful to anyone who has thought about installing a slide lock.

[Gary WA]

Nice work!

[CHuDWah]

Originally Posted by Superhart

...Yes, I realize there is a possibility of locking myself out of the car and having to break a window to get in...

Just to emphasize this for others who may be considering installing a passenger-side slide lock...

If a door is slide-locked, it cannot be opened from the outside, even with a key. So if one slide-locks a door, exits the other door, slide-locks and closes it, there is no way to open the car without breaking into it.

[Superhart]

Today I welded the spring retainer post onto the right latch, ground down the weld and finished assembling the modified latch. Here are the latest photos.







Now to prime and paint the latch to match body color and install. If anyone has a photo of the inside of a right side door with the trim panel removed I would appreciate it. Also, what is the best way to remove the window crank handle without purchasing that expensive tool the web sites sell?

[CHuDWah]

Originally Posted by Superhart

...If anyone has a photo of the inside of a right side door with the trim panel removed I would appreciate it. Also, what is the best way to remove the window crank handle without purchasing that expensive tool the web sites sell?

Ask Mr Google - he has lots of pix.

The window riser handle is held on the shaft with a pin, which is hidden by the escutcheon. There is a conical spring on the shaft behind the trim panel - it pushes the escutcheon against the handle. Probably the best way to remove the handle is to purchase that expensive tool. Otherwise, press the escutcheon against the panel to expose the pin, then push it out with a punch, nail set, wire, whatever. It helps if you have at least three hands. If you don't, recruit an assistant to press the escutcheon - there will be more room for both of you to work if he/she reaches through the open window from the outside. Re-installation is the reverse of removal.

[Superhart]

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After installing the modified latch mechanism I removed the door panel on the passenger side. The inner steel door liner was stamped for installation of a sliding lock but no D-nuts were installed. I obtained them (10-32 thread) from Snyders and installed them. The D-nuts or rivet nuts obtained from Snyder’s were not a press-in fit as I had hoped. Apparently the factory pressed them in and peined over the front edge to lock them in place. With an assembled door there is no easy way to accomplish this so I opted for good old Epoxy. I trimmed off the front edge of the nuts with a grinding wheel to make the installation seat properly and sanded and cleaned the backside of the inner door panel through the door latch slot. I needed a scoured and clean bonding surface. One by one I applied a bead of clear epoxy around the seat of the nut and guided it into place from the back side of the inner door panel. I secured each nut with a 10/32 screw and brace plate from the front side to hold the nut in proper position until the epoxy set. Mission accomplished.












When I went to install the sliding lock it seemed to begin to engage even when in the open position so I had to remove the door latch and do some bending and finagling to finally get the operation to act properly. Then I screwed everything back in place.

Next was to install the escutcheon plate on the inner door panel. I measured, marked and carefully cut the location hole for the sliding latch and installed it by bending the tabs on the escutcheon plate around the backing plate. Finally, the door panel was buttoned up. I never did completely remove the inner trim panel, just pulled it forward at the rear edge enough to gain necessary working room. I did the necessary cutting from the front using a new single edge blade and a fine tooth fret (jeweler's) saw from my days as an amateur banjo luthier. That way there was no question about the alignment of the slot.








Finally, a working passenger door sliding lock assembly. I hope this article is helpful to anyone who has ever thought about performing this modification.

[Superhart]

Just posted photos of the end result of installation.

[john charlton]

Your right door was stamped to accept a sliding lock as RHD cars the sliding lock is on the right side . The locking handle is on the right drivers door . So you can have a LHD and RHD door . The RHD door will have a "AF" part number .There is a LHD and RHD lock as well .

John in breezy Bath Somerset County England ,

[Superhart]

I attempted to get a right door latch with sliding lock from three different dealers in right hand drive countries. They all said the right latch with sliding lock mechanism was not available. That’s why I proceeded with the modification. Go figure.

[john charlton]

Probably not enough call for them . We land up having the key lock handle on the drivers side . Not much fine point judging in RHD countries .

John in same place .