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      04-30-2017, 06:58 PM   #1
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Drives: 2011 128i
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Replacing door lock actuator

The other week my passengers-side door completely stopped locking and unlocking. The little lock plunger thing was down, looking like the door was always locked, but I/anyone could just pull the handle and the door would open. So after some research here, I decided to replace the door lock actuator. There were one or two useful threads in this forum, and lots of stuff for the 3 series, but not much for our cars so I figured I'd write this up. I'm mildly handy, (do my own oil changes, coolant flushes, and brake jobs) and this job too me about 2 hours and really wasn't that difficult.

- new actuator (part # 51217263086), I got a pair (left and right) for $55
- some people say you'll want some new panel clips in case you break some removing the door panel, but I managed to not break any.

- T-20 torx bit
- T-30 torx bit
- 10mm socket
- razor blade
- plastic panel removal tool
- some sort of metal pick


1. First you'll need to remove the interior door panel. I followed this video to a T and it had everything:
Like the guy says in the video, the panel is really clipped on tightly, so it'll take some pulling to get it off. He starts in a corner when he begins prying the panel off, but I had no luck with that so I started in the middle of the bottom side and it came off no problem. Once the panel is off and the speaker wire and lock cable are off, you'll still have the other end of the lock cable attached to the actuator. Just pull down on the white bit and then pull away from the actuator housing, and it'll pop right out. Finally, remove the lock rod by simply pulling it straight out from its hole.

2. Once the panel is off and everything disconnected, you'll need to use your razor blade to cut out the vapor barrier foam. The sealant BMW used is applied pretty thickly, so you'll be able to run the razor blade down the middle of it. This means that there's sealant left on both the metal of the door and the vapor barrier so reapplying the barrier when you're finished will be easy. You only need to cut about half of the barrier off.

Vapor barrier:

Vapor barrier half-way removed:

3. Next you need to get the old actuator unit out. First, if you look inside the door at the actuator, you'll notice that there a cable coming down from the top of the door that attaches to the actuator with two holding points. Disconnect this cable by holding it and pulling it straight away from the actuator. The cable will pop right out of its holding mounts.

Inside view of the door showing this cable. You can see the two mounting brackets that hold the cable in place.

4. Next, remove the three screws holding the actuator in place. Use the T30 torx bit for these. Once all three are out, the old actuator is completely free to move around.

5. Removing the actuator from its compartment inside the door is annoying. To help, loosen the two bolts on the underside of the door frame that are holding the window guide track in place. I wouldn't recommend removing these, but I loosened them and it gave me a few mm of wiggle room which was enough. Basically try your hardest to get the old actuator out. I probably spent 5-10 minutes trying every possible position before I finally managed to jimmy it out.

This is the actual orientation of the old actuator when I finally got it out. Put the new one in starting in this exact position.

6. Wrapping up. Now the hard parts are all done. Get the new actuator in the door, screw it in place good and tight, replace the cable on the back, plug the new actuator in, replace the vapor barrier (be very sure to get a good seal), then reattach the various wires and then the interior panel. The only issue I had with all this was getting the locking rod to stay in place: every time I pounded the panel back in place the rob fell out of its hole and I had to remove the panel again. Turned out the rod was not fully seated in its socket. Really push it in there and you'll hear a good click.

One last note: with the new actuator, you kinda have to push the door closed a little bit harder than before to actually fully close the door. Hopefully this has to do with the part being new and it'll relax a little over time.

Here's a gallery these images as well as a few others:
View post on

Hope this helps, feel free to post here with any questions and I'll do my best to answer them.

Last edited by leagues58; 04-30-2017 at 11:27 PM..
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      05-17-2017, 06:39 PM   #2

Drives: 08' 135i
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Do you happen to have a picture of how the interior door handle cable was connected?
I can't seem to get enough tension so that the interior door handle unlocks the door.
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      08-26-2017, 02:52 PM   #3
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Drives: Montego Blue 2008 135i
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Originally Posted by Xer89101 View Post
Do you happen to have a picture of how the interior door handle cable was connected?
I can't seem to get enough tension so that the interior door handle unlocks the door.
Here's the pic from my drivers side. I replaced that one today and will add a few notes about it later.

Notes from my driver side replacement:

* If you have comfort access there are two wire holders that you need to remove. These took forever for me to figure out how to get out. Feel around the back of the latch assembly and you'll find them. Pull/rock out the holder by twisting parallel to the wires. If you try to pull straight out they probably won't budge. If you pull/rock them out they will free. Imagine a T. Roll and pull the top part of the T so that the lower part (the plug if you will) wiggles out. It's much harder to explain in words.

* I used a razor blade to cut the sticky adhesive on the vapor barrier. I took my time and basically cut it so that there was still a layer on the barrier and the door. This make reassembly super easy and preserved the seal. I took my time on this so as not to cut the vapor barrier.

* You have to remove the door lock cylinder if you have a key hole. Near the top behind a plug is a 4mm Allen screw. Remove that. Then while holding the exterior handle a bit open, pull straight out the right hand piece with the lock. It may help to actually rotate the cylinder a bit with the key. It basically snaps in and comes straight out.

* I made sure during all steps to measure and mark how things were aligned. This included the latch in the door plus the window regulator clearance. I had to loosen the lower mount for the regulator to move it just a few mm to make clearance.

* I tapped up the side of the door near the latch and make markings of where different parts lined up.

* Getting the latch assembly out is tricky. Take your time. I had the press the regulator toward the outside of the door to make room. It was very tight.

* The screw holes on my new latch assembly weren't tapped. At first I thought I was stripping the threads, but that wasn't so. Just line things up and take your time so you get it right when you start tightening the mounting screws.

* Double and triple check everything is lined up, working, connected, and snapped into place.

* It wasn't a hard job but just a bit frustrating at times. It took me about 3 hours start to finish but that was me taking more time than needed to make sure things were perfect.
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      09-26-2017, 04:13 PM   #4
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Drives: 2008 128i
Join Date: Jan 2014
Location: Ft.Lauderdale,Fl

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I did the drivers side today. What a pain in the ass to remove the actuator. I loosened the adjusting nut for the window regulator that's in the bottom of the door. To readjust it I closed the door and tightened it from inside . Window shut perfectly.
The new unit also seemed smaller or less bulky and went in much easier. You'll need all the patience you can muster to complete this DIY.
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      09-30-2017, 11:44 AM   #5
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Drives: '08 128i
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Garage List
2008 BMW 128i  [5.00]
2014 BMW 528i  [5.00]

Here's the positioning and range of motion I used to get it out. I knew it was gonna be a tight fit but good lord guys if it were 1mm taller in any area I doubt you could get it out. Resorted to using the rubber mallet on it a few times to help it rotate.

My 2008 128i - Sparkling Graphite/Beige - Sport pkg - 6MT - Click me!
Parents' 2014 528i - Mineral White/Ivory White - fully loaded
Instagram @Andreys_128i
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      11-21-2019, 08:57 PM   #6
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Drives: 2010 BMW 135i
Join Date: Aug 2017
Location: SoCal

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FYI for the driver side lock cylinder. The rubber grommet covers the Allen key and itís located on the outside of door a few inches above the latch Mechanism. Itís a small circle rubber grommet size of a penny. Couldnít find it at first.
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actuator, actuator problems, door, lock

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