Need help diagnosing passenger door latch fault

[HankLloydRight]

Hello folks,

The passenger side door latch is not opening the door (open or close). I can hear the linkage operating, and when the door is closed, pulling the latch does release the locking pin (loud pop sound), but the door does not operate. The door operates fine using the outside door button. Driver's side door and latch operate normally.

I'm not sure where to begin diagnosing this issue as it appears to be electrical.

I've reviewed many of the disassembly pages below, but there are so many different possible ways to go, including:
RIGHT REAR SIDE PANEL: https://www.bmwz1.org/Reparaturanleitun ... 5000b.html
DOOR PUSH BUTTON: https://www.bmwz1.org/Reparaturanleitun ... 10000.html
REMOVING AND INSTALLING MICROSWITCH FOR DOOR CONTROL: https://www.bmwz1.org/Reparaturanleitun ... 1000c.html

CHECKING MICROSWITCH FOR DOOR CONTROL: https://www.bmwz1.org/Reparaturanleitun ... 1000e.html
ADJUSTING LINKAGE FOR DOOR PUSH BUTTON: https://www.bmwz1.org/Reparaturanleitun ... 1000a.html
--- these two talk about a 'test box' 611459 and adapter lead 611452. Does anyone have these tools?

REMOVING AND INSTALLING DOOR LOCK SWITCH (CENTRAL LOCK DRIVE): https://www.bmwz1.org/Reparaturanleitun ... 60000.html

...as well as several other possible options.

Any help would be most welcome where to start finding and fixing the fault.

Thank you.

[Stoertie]

Hello folks,

The passenger side door latch is not opening the door (open or close). I can hear the linkage operating, and when the door is closed, pulling the latch does release the locking pin (loud pop sound), but the door does not operate. The door operates fine using the outside door button. Driver's side door and latch operate normally.

I'm not sure where to begin diagnosing this issue as it appears to be electrical.

First check the linkage from the door handle to the lock mechanism. If it is a little too long, the mechanical part will work, but the microswitch will not start the door motor.
Outside next to the seat is an inspection hole. There you can adjust the length of the linkage.

regards
Michael

[HankLloydRight]

Outside next to the seat is an inspection hole. There you can adjust the length of the linkage.

Can you please explain where this is? Is there a guide page on https://www.bmwz1.org/ that shows this?

Thank you.

[Stoertie]

Hi,

beneath the seat is a round cut in the carpet. Behind this "carpet flap" is the inspection door. It's a round piece of sheet metal, that is fastend with two screws. Adjustment of that linkage isn't explaint in the repair manual.
Inside you cyn find the actuator for central closing and the adjustment screw for the linkage (one side has a rh winding the other has a lh winding)

I recommend to take out the seat for this job, that makes the work much more comfortable.

The insp. hole is located nearly at this positionhere but at the inside of the car:

151065.jpg (10.12 KiB) Viewed 19507 times

Regards
Michael

[HankLloydRight]

Great, thank you! I'll give this a shot and let you know.

[Stoertie]

You can also test it a little easier...

After initializing the door (pull out the fuse for a few seconds), push in the door lock. after the door is closed, open it again from the outside.

Now take out the door handle and pull the linkage with your hand to the front, if the door motor starts, it is sure that it is an adjustment thing.

But then you have to proceed as described before anyway.

Regards
Michael

[TJS]

My doors could do with being serviced and overhauled which is currently beyond my post surgery DIY door belt replacement skills. Any recommendations ?

Have the BMW updated the construction ? I bought a spare drive belt 3 years ago which had a 2010 date stamp on the box, fitting a 10 year plus rubber component is a false economy when you go to the trouble and expense of stripping down the doors. A number a rubber cam belts are now available with kevlar reinforcement for longevity.

[bluejay]

RKV trading (René Visser) is probably the best place to go to in Europe.

He is THE Z1 door specialist.

He is not cheap but does excellent work

[HankLloydRight]

Ok, folks, need more help with the door latch.

I took the car to a local independent shop that specializes only in BMWs (we've taken our other BMWs there and it's a really great shop).

The tech who was working on my car knows E30s phenomenally well, and is knowledgeable about most 80's BMWs, so I trust his skill and capabilities.

He took apart all the passenger panels he could (after removing the seat) and could not find the problem. He did try all the adjustments outlined in the online Z1 repair guide. His next step was to remove the door to access the linkage between the door latch and the door microswitch, but due to limited shop space, he wasn't able to do that. So now I have the car back, re-assembled but no fix.

He thinks the linkage is broken somewhere inside the side or door panels. We can hear the linkage operate up to a point, but not like the driver's door. So we really don't know where or how to further diagnose this issue. To reiterate the problem, the outside door button works perfectly to open and close the door. The inside door latch does nothing.

My next step is to take the car down to some good friends of mine on Long Island who have rebuilt and restored dozens of cars -- several Deloreans, NSX, Porsches,etc. They've also done engine swaps and custom door openers for the Delorean and lots of other projects. So I think the three of us are going to try next.

But from the collective Z1 hive-mind -- where should we look? How can we go about finding the core issue? Has anyone else had this problem?

Thanks.

[Jet]

where should we look? How can we go about finding the core issue? Has anyone else had this problem?

I had this issue, inner door handle not activating the switch and lowering/raising the door. Oddly, it was worse in Summer, following the advice from Stoertie and adjusting the linkage (small increments) through hole next to the seat, it worked.

Did anything occur before the issue started, that might have caused it? It might help if you go back to the beginning, its possible something was missed? Follow the steps from Michael, who has an excellent knowledge of troubleshooting door issues, eliminate each step and report back. And remember, "Too many cooks can spoil the soup", you might make it worse.

A Delorean is easy compared to the design of a Z1 Door

[Jet]

I bought a spare drive belt 3 years ago which had a 2010 date stamp on the box, fitting a 10 year plus rubber component is a false economy when you go to the trouble and expense of stripping down the doors. A number a rubber cam belts are now available with kevlar reinforcement for longevity.

You say that Mr T, but.....I got an email from a chap last week, the door belts on his 1992 car were the originals before being changed in 2022, 30 years is pretty impressive.

[F.Brossaud]

Mine is from July 1990, original belts and doors are still working perfectly
"Never touch a running system"... can be good approach for Z1 doors

[Stoertie]

"Never touch a running system"... can be good approach for Z1 doors

Perfect view!
Nobody needs the Z1 as a vehicle for everyday use anymore, so you can safely wait until something stops working and then fix it. - Especially with the astronomical prices for spare parts.

[HankLloydRight]

Ok folks, I was able to get both my door problems fixed.

For the passenger inside latch that wasn't working, the problem was what people suggested above -- the adjustment behind the removable panel behind the carpet next to the seat. Seat removal helped a lot here. Tip #1: Moving the seat to a medium/middle height will make it easier to remove both the front and rear bolts. Once we removed the small panel we had to contort to fit two 15/64" wrenches to loosen the lock nuts and turn the turnbuckle "up" in effect pulling the rods closer together. Luckily one guy in our group was pretty small and had an easier time fitting in the car where the seat was in order to turn the wrenches. Keep in mind this turnbuckle is much much smaller than it looks in the photo below.

pax-turnbuckle.jpg (37.49 KiB) Viewed 18741 times

The other thing that was strange and we discovered was that we had to pull --and hold-- the inside door latch for about 1 to 3 seconds before the door would operate. This came as a surprise as the door wasn't working and my friend just happened to pull and hold the latch for a couple of seconds and BOOM -- the door operated both up and down. Also while working on the passenger door we could see that it took a few tries of up+down to get it to calibrate itself and start working.

On the driver's side, my outside button stopped working. We removed the square panel on the inside of the fender right behind the door button. The online instructions say removing the roof makes this easier, but we did not have to do that. Once removed we could see that when we pushed the outside button, it was not pushing the lever (blue arrow) far enough forward to engage the microswitch. There are two connecting rods with knuckles connected to the mechanism. The top one is for the central locking, and the lower one controls the door. We disconnected the lower knuckle (green arrow) from the connecting rod, and turned the knuckle "up" about three turns to lengthen the throw of the connecting rod. We used a very long needle-nose pliers to do this. We then re-attached the knuckle to the connecting rod stud and that fixed that problem.

drivers knuckel1.png (247.92 KiB) Viewed 18741 times

Here's a better shot of the lower knuckle you need to pop off the connecting rod.

drivers knuckel2a.jpg

(77.71 KiB) Not downloaded yet

I do have one question for the group. Both my outside door buttons are "sticky" and seem like they need some lubrication to make their operation smoother. What lubricant do you recommend? WD-40? Graphite powder? Garage door lube spray? Something else? Thanks.

[Jet]

Cleaning to begin with, that area behind the cover gets clogged. Also check the rear quarter panel is not cracked above the button and impeding movement.