Need door lock advice for 1981 F150

[JohnnyD]

I have an 81 F150 two-door, 2WD, just turning 200K that is having problems with one door latching and I suspect the other is on the way out, too. I replaced both of the pins (with the plastic insert) that mount in the door jam several years ago and these look like there in good shape. The passenger door only latches if you slam the heck out of it, and then if you pull in and out it has slop in the mechanism. The new door rubber is all that keeps it from rattling. I suspect the lock mechanism itself is dead. The driver's side latches OK, but it also has slop in it when closed.

My question is if there is only one type of lock mechanism in 1981. I have the sliders and think that the pin-type locks do not have interchangeable lock mechanisms. When I look at, say, LMC Truck, they only show one. I don't want to shell out $160 to do both sides only to find that I have to send the part back because it doesn't work with the slider mechanism.

Advice? Perhaps a recommended source?

Thanks

[Gary Lewis]

The pin locks were phased in during '81, but the latching mechanism is interchangeable with one minor difference: if you put a pin style lock in it'll lock in the unlock position and vice versa.

To say it differently, if you put a slide-style lock in a pin style door lock will be with the button pulled up and unlock with be with it pushed down. Similarly, a pin-style lock in a slide-style door will have it locked in the unlock position.

But otherwise the locks are identical and can be swapped.

[JohnnyD]

The pin locks were phased in during '81, but the latching mechanism is interchangeable with one minor difference: if you put a pin style lock in it'll lock in the unlock position and vice versa.

To say it differently, if you put a slide-style lock in a pin style door lock will be with the button pulled up and unlock with be with it pushed down. Similarly, a pin-style lock in a slide-style door will have it locked in the unlock position.

But otherwise the locks are identical and can be swapped.

Thanks, Gary, for the prompt and informative reply.

[Gary Lewis]

Thanks, Gary, for the prompt and informative reply.

Let us know what you do and how it goes, please. That's how we learn.

[FuzzFace2]

I have an 81 F150 two-door, 2WD, just turning 200K that is having problems with one door latching and I suspect the other is on the way out, too. I replaced both of the pins (with the plastic insert) that mount in the door jam several years ago and these look like there in good shape. The passenger door only latches if you slam the heck out of it, and then if you pull in and out it has slop in the mechanism. The new door rubber is all that keeps it from rattling. I suspect the lock mechanism itself is dead. The driver's side latches OK, but it also has slop in it when closed.

My question is if there is only one type of lock mechanism in 1981. I have the sliders and think that the pin-type locks do not have interchangeable lock mechanisms. When I look at, say, LMC Truck, they only show one. I don't want to shell out $160 to do both sides only to find that I have to send the part back because it doesn't work with the slider mechanism.

Advice? Perhaps a recommended source?

Thanks

Am I reading this right?

You installed new door weather seals and now the doors don't close right?

If so this is normal till the seals "break in" and flatten out some.

What you are seeing with the latch is it has 2 locking positions and I bet with the new seals it is only catching the first catch. You can see this if you open the door and using something to push the latch to close it will click for the first catch (that I think you are getting now) and if you push it a little more it will get to the second catch.

Now make sure the latch will work right clean it and re-lube first.

Then you will need to adjust the post out just a little so both catches catch.

You may need to slam the doors till the seals flatten out and adjust the post in a little again so both catches catch. Keep adjusting the post inover time till the door fits right.

BTW my truck I had to slam the right door a few times when I installed new seals.

Been almost 2 years and I dont need to slam it as much now that the seals have flatten.

Dave ----

[JohnnyD]

I have an 81 F150 two-door, 2WD, just turning 200K that is having problems with one door latching and I suspect the other is on the way out, too. I replaced both of the pins (with the plastic insert) that mount in the door jam several years ago and these look like there in good shape. The passenger door only latches if you slam the heck out of it, and then if you pull in and out it has slop in the mechanism. The new door rubber is all that keeps it from rattling. I suspect the lock mechanism itself is dead. The driver's side latches OK, but it also has slop in it when closed.

My question is if there is only one type of lock mechanism in 1981. I have the sliders and think that the pin-type locks do not have interchangeable lock mechanisms. When I look at, say, LMC Truck, they only show one. I don't want to shell out $160 to do both sides only to find that I have to send the part back because it doesn't work with the slider mechanism.

Advice? Perhaps a recommended source?

Thanks

Am I reading this right?

You installed new door weather seals and now the doors don't close right?

If so this is normal till the seals "break in" and flatten out some.

What you are seeing with the latch is it has 2 locking positions and I bet with the new seals it is only catching the first catch. You can see this if you open the door and using something to push the latch to close it will click for the first catch (that I think you are getting now) and if you push it a little more it will get to the second catch.

Now make sure the latch will work right clean it and re-lube first.

Then you will need to adjust the post out just a little so both catches catch.

You may need to slam the doors till the seals flatten out and adjust the post in a little again so both catches catch. Keep adjusting the post inover time till the door fits right.

BTW my truck I had to slam the right door a few times when I installed new seals.

Been almost 2 years and I dont need to slam it as much now that the seals have flatten.

Dave ----

Dave, thanks for this input. I think the door seals are well squished after a year. Also, when I first put the seals in, I couldn't get the doors to latch at all, so I adjusted the post until it latched. At that point, there was a 1/4" gap between the door edge and the cab. Now they'll close without the gap. The symptom that the doors both have some give when I pull on them when locked makes me still think the mechanisms are just worn out from 40 years of work.

I already ordered the parts, so we'll have to see what plays out. I'll keep y'all posted.

[JohnnyD]

The pin locks were phased in during '81, but the latching mechanism is interchangeable with one minor difference: if you put a pin style lock in it'll lock in the unlock position and vice versa.

To say it differently, if you put a slide-style lock in a pin style door lock will be with the button pulled up and unlock with be with it pushed down. Similarly, a pin-style lock in a slide-style door will have it locked in the unlock position.

But otherwise the locks are identical and can be swapped.

Perhaps someone has some advice for a work-around for this problem. My RH door latch (81 F150) is barely functional, requiring heavy slam to secure, and then still loose on the jam pin. I have replaced the pin and adjusted it with no improvement (details in original post). I suspect internal wear (200K mi). I bought the replacement latch from LMC Truck after discussing my concerns with the sales rep. My concern is that I know my version with the slider inside lock was only produced within a narrow production window, and even some of the 81s have pin-type locks on the window sill. I was assured this lock would fit; there is no alternative I can find. Gary also indicated that he thought the only problem was that the lock/unlock position might be reversed (I can live with that).

So I bought a new latch and dug the old one out of the door (note, remove window channel first for better access). At first glance they look the same. Figure 1 compares the two (sorry it needs to be rotated CCW 90 deg; maybe lay down to view?). This is viewed as if you were inside the door panel, so the actual latch is on the back side to the right.

Figure 2 shows the Ford original one with the operator rods attached. The outside door handle and outside lock rods (left side) move straight up and down, parallel to the back of the latch chassis. The inside handle and lock rods (right side) move perpendicular to the back of the latch mechanism, toward the viewer and slightly to the right. You can see that the inside lock rod connects to a rotating plate that has a notch at the lower left that engages with the actual locking mechanism in the main latch chassis.

Figure 3 shows the LMC replacement part (49-7241). The outside door handle, outside lock, and inside door handle appear to work identically to the Ford original. However, note that the inside lock is setup for a pin lock, not a slider and that they don’t seem to be interchangeable. Whereas the original rod pulled perpendicular to the latch (out of the picture, slightly to the right of the viewer), the LMC one pulls parallel to the latch (upward in the picture). You can see that essentially the swivel plate with the notch from the Ford one is missing.

I have already replaced the door panels with ones that have slide locks. I could buy pin-type rods and drill a hole in the top of the door panel, but this would be a second choice. Any other ideas on how to conquer the beast?

Thanks, everyone,

- John

 

[grumpin]

Perhaps someone has some advice for a work-around for this problem. My RH door latch (81 F150) is barely functional, requiring heavy slam to secure, and then still loose on the jam pin. I have replaced the pin and adjusted it with no improvement (details in original post). I suspect internal wear (200K mi). I bought the replacement latch from LMC Truck after discussing my concerns with the sales rep. My concern is that I know my version with the slider inside lock was only produced within a narrow production window, and even some of the 81s have pin-type locks on the window sill. I was assured this lock would fit; there is no alternative I can find. Gary also indicated that he thought the only problem was that the lock/unlock position might be reversed (I can live with that).

So I bought a new latch and dug the old one out of the door (note, remove window channel first for better access). At first glance they look the same. Figure 1 compares the two (sorry it needs to be rotated CCW 90 deg; maybe lay down to view?). This is viewed as if you were inside the door panel, so the actual latch is on the back side to the right.

Figure 2 shows the Ford original one with the operator rods attached. The outside door handle and outside lock rods (left side) move straight up and down, parallel to the back of the latch chassis. The inside handle and lock rods (right side) move perpendicular to the back of the latch mechanism, toward the viewer and slightly to the right. You can see that the inside lock rod connects to a rotating plate that has a notch at the lower left that engages with the actual locking mechanism in the main latch chassis.

Figure 3 shows the LMC replacement part (49-7241). The outside door handle, outside lock, and inside door handle appear to work identically to the Ford original. However, note that the inside lock is setup for a pin lock, not a slider and that they don’t seem to be interchangeable. Whereas the original rod pulled perpendicular to the latch (out of the picture, slightly to the right of the viewer), the LMC one pulls parallel to the latch (upward in the picture). You can see that essentially the swivel plate with the notch from the Ford one is missing.

I have already replaced the door panels with ones that have slide locks. I could buy pin-type rods and drill a hole in the top of the door panel, but this would be a second choice. Any other ideas on how to conquer the beast?

Thanks, everyone,

- John

At first glance, I would think an extension on the inner door lock rod. And I have no ideas of how to accomplish that.

Man, that’s a bummer!

[JohnnyD]

At first glance, I would think an extension on the inner door lock rod. And I have no ideas of how to accomplish that.

Man, that’s a bummer!

Dane, unfortunately it is more than an extension of the rod. The new one operates at right angles to the old one. To unlock, you'd pull up on a pin or knob on the window sill (like most cars with manual door locks) vs the old one had a slider that slides back and forth above the inside door handle. Arghhh!

[Gary Lewis]

Dane, unfortunately it is more than an extension of the rod. The new one operates at right angles to the old one. To unlock, you'd pull up on a pin or knob on the window sill (like most cars with manual door locks) vs the old one had a slider that slides back and forth above the inside door handle. Arghhh!

Let me check tomorrow, but there is a chance I have an extra slide-style lock. I think I might 'cause Cash swapped out his sliders to pin style and he's the one that discovered that the slide style locks work backward when used with pins.

And I also want to compare the LMC lock with a factory pin-style lock as I think they may have made the locks differently. If so, that's what your problem is.