620 Door Not Latching - FLIES OPEN going around corner!

[Cardinal Grammeter]

EDIT:  DIAGNOSED AND FIXED:  Scroll down to the post with the parts diagram.

 

I sure scared some people as I took a corner pretty hot trying to preserve some momentum (!)  This has happened before but I thought it just wasn't fully latched.

 

Haven't gotten into it in detail but the pawl seems to be latching when manually rotated as well as the release working.  (However, the sound of the pawl locking into both the ajar and closed positions is very weak and not the robust, loud, solid metal clang of the passenger door.)

 

Door does not latch even in the ajar position.

 

It behaves like the striker is not rotating the latch pawl.  Carefully, slowly closing door, there is no click of the pawl locking into place - how is this possible?

 

The striker plate is very worn but looks just like the one on the passenger's side.

I'm thinking something failed (a spring?) in the door latch mechanism.

 

 

Edited October 6, 2022 by Cardinal Grammeter

[Stoffregen Motorsports]

Wear can cause the problem, but so can dirty components. Try squirting it down with WD40 and work it back and forth a few times. This may just do the trick.

[Cardinal Grammeter]

It is clearly the door latch mechanism:

*) The rotating pawl now only latches at Ajar - there is no latch at Closed.

*) When latched at Ajar, pawl can be popped out with channel locks w/ little effort.

*) The interior release handle begins engaging at almost full open position (the other door you can feel a long engagement as a spring is compressed)

*)  The Exterior release handle only opens a small about 1/4 to 1/2" instead of the long 1" travel of the other door.

*)  When closed, the interior door lock knob will not move down to lock door.

 

I believe there is a spring that is broken or there is some obstruction.  There is no loud "clang" when the rotating pawl latches.

 

I think I'm going to buy a latch mechanism since this is my only vehicle being driven and the last thing I want to do is open up the door, remove the mechanism and see that it is not repairable.  

 

Sucks when only 1 car to drive.

 

EDIT:  I found a pic of the latch mechanism and you can see the massive 2-step ajar and closed pawl.  Clearly, rotating the latch open w/pliers indicates the massive internal pawl is not even engaging.  So must be spring or rusted pawl pivot.

 

 

Edited October 3, 2022 by Cardinal Grammeter

[Cardinal Grammeter]

WTF - Nylon Nut #30 (90609-H1400) was LOOSE  AF on the threaded rod coming from the door exterior release handle.  IT WAS SLOWLY WINDING ITSELF LOWER (due to gravity I guess) UNTIL IT WAS LITERALLY KEEPING THE MECHANISM LATCH PAWL FROM FULLY ENGAGING - AS IF THE EXTERIOR HANDLE WAS PULLED UP TO RELEASE THE LATCH.

 

Why?  Did the nylon nut become so loose (finger tight would overstate it - it was ZERO tight and turned like on ball bearings.  I sprayed the inside of the door with fluid film when I welded up the truck almost 10 years ago - did FF attach the nylon and cause it to swell? 

 

Now I have to figure out how to keep the nut from unwinding again.

 

QUESTION:  Has ANYONE ever had this happen????????

 

Edited October 5, 2022 by Cardinal Grammeter

[iceman510]

Interesting.  On one of my 510s, I just screwed those down lower on the rod since it seemed when pulling the outside handle the rod traveled far before actually releasing the latch.  I will have to see if that was too much to lower it.  Maybe there needs to be some gap for proper operation.

 

[Cardinal Grammeter]

I would say adjust it so there is some free play.  

 

Mine had massive "negative" free play that only allowed maybe 10% engagement of the latch pawl - I could gently bump door with shoulder and it would open.

 

I have another interesting post on the crack failure of the top hinge which is related to wear in the spring nest.

[Cardinal Grammeter]

3 hours ago, iceman510 said:

Interesting.  On one of my 510s, I just screwed those down lower on the rod since it seemed when pulling the outside handle the rod traveled far before actually releasing the latch.  I will have to see if that was too much to lower it.  Maybe there needs to be some gap for proper operation.

 

How loose was that nylon adjusting nut the threaded rod end?  

[iceman510]

I don't recall it being difficult to turn down, but it was not without some resistance, so some force was required.

[Cardinal Grammeter]

18 minutes ago, iceman510 said:

I don't recall it being difficult to turn down, but it was not without some resistance, so some force was required.

Interesting - mine turned like a ball bearing.  I gave it a large dose of Purple Loctite (the one for light duty and/or small fasteners like carb screws.)