New Rear Hatch for Der Wagen

*blows on mic* Is this thing on? It’s been a long time since I posted something here, lets see if it still works.

This weekend was spent swapping a new hatch onto the BMW 528i Wagen. (Warning, very long post.)

This spring I put my wagen up for sale on Craigslist. I was tired of working on it, it needed new rear tires for summer, the rust hole in the rear hatch was getting really big, and I just didn’t want to deal with it anymore.

I got a few nibbles, but nothing serious (except for the kid who wanted to trade his 99 Prelude for it – which I considered…) But I did get contacted by a guy who said “I can’t decide if I want to buy your wagen, or sell you the rear hatch that I have that would fit it. It’s even the right color.”

Apparently he had a 2000 528i wagen and had bought a used rear hatch for it but then his wagen got totaled. He decided that he didn’t really want another vehicle (he has several) and I got a case of the crazies, so I bought the hatch from him.

Why can’t I bring myself to sell this BMW?

So I decided to keep the wagen for a while longer and bought some new rear tires.

The hatch needed a little cleanup – it had a few small rust spots, but it was in much better shape than the one on the car. So I spent a little time working it over and touching it up.

I figured that I’d better get the hatch installed before the weather really goes to crap, so Saturday I got started.

The first thing was the wiring harness. The new hatch had the four (four!) harnesses clipped off when it was removed from the donor car, so I stripped them out. The guy I bought it from told me that there were connectors up under the headliner, so I should be able to pull my harnesses out and run them into the door. So I decided to investigate and find these connectors. (Spoiler: there are no connectors.)

In order to get the headliner down, you have to pull the gasket and the two D pillar covers. In order to pull the two D pillar covers, you need to pull the plate across the bottom of the door frame. In order to pull that you need to remove the rolling floor tray and two rollers. Then in order to pull the headliner low enough to see what’s above you need to pull off the C pillar covers. This job is already a hassle.

Once I got the headliner down I discovered that the wiring harnesses snaked into the area behind the speakers that are mounted in the ceiling. So I took those out. The wires just passed through that area and then back out again. No sign of anywhere to unplug them. The harnesses continued forward and into the C pillars. At that point I gave up and decided I would just remove the harnesses from the door and glass in situ and then install them into the new ones on the car. Which actually turned out to be pretty easy and the correct choice.

So, onward. I opened the glass and stripped out the harnesses. Oh, wait, not so fast, first I had to remove a bunch of plastic. Then the two wiring harnesses, followed by four nuts and the glass was off.

Finally, progress. Got the glass off.

Then I stripped all the plastic off the inside of the main hatch and removed the wiring harness from each side. No real photos of that, but here’s a bunch of rust.

This is the big rust hole in the hatch. You can barely see the wires for the harness disappearing into the rust.
One corner of the glass. Chunks of rust would fall off every time I opened it.
The other corner of the glass. Just as bad.
Actually, the whole bottom edge of the glass was shot. It’s a bad design, the water collects and the edge sits in it.
The rust hole in the hatch after removing the wiring harness.

Okay, after I removed the wiring harnesses I needed to stop for some late lunch. It was supposed to rain in the afternoon and I was doing this work in the driveway so I figured I’d better tarp up the rear of the car.


It was a good thing I did, since it started raining while I was eating. It continued to rain all afternoon and into the night. We had a inch of rain in the gauge on Sunday morning but I’m glad to say that the tarp kept the water out of the car.

Sunday morning was sunny, but chilly. I’ll take chilly over steamy hot any day, so I put on a sweatshirt and got back to work.

The first thing was to repair the wiring harness. It’s a known issue that the wires tend to break in these and I had already fixed one issue in the past. I took a look and discovered there was another wire that had broken, so I grabbed my soldering iron and spliced in some new wire. I also cleaned up my previous repair, since I had the whole harness out and it was easy. The photo is pre-cleanup, so ignore that heatshrink/tape blob on the red/white wire.

Wire mess. (Also star-nuts.)

The gas springs that support the glass and door were shot and had to come out. I figured that I had better disconnect them before I unbolted the hinges from the car since they were still under pressure, so that was next. It was pretty rusted, so that took a bit of beating and prying, but I got them off.

Next up was the 8 bolts for hinges. The new hatch came with hinges attached, and they had less rust, so I figured I would just swap them in with the door.

The hinge bolts had other ideas. They were T-40 (I think, big anyway) Torx heads and half of them didn’t want to loosen, so they stripped. So, decision time. Do I drill these out and order new bolts (and wait a week), or do I re-use the existing hinges and try to loosen the “star nuts” that hold the hatch to them?

The existing hinges were not actually that bad, so I figured I would just figure out how to deal with the star nuts. So I thought about it a bit, grabbed my Vise-Grips and loosened the star nuts. Worked a treat. (You can see the star nuts in the previous photo.)

So here we are, hatch completely removed.

Big hole in the back of the car.

I only had to swap the lower latch mechanism from the old hatch to the new, the new one already had the glass latch and wiper motor installed.


I figured the next thing to do was remove the gas struts from the car and start putting the new ones in. The struts go into the roof of the car, and you can’t see what you are doing.

Struts go in here.

Removing those struts turned into a pretty big time sink. I did some reading on the forums and one suggestion was to get some 1-1/2″ copper pipe to use to pop the struts off the ball joints. So I walked up to the hardware store and bought some.

The pipe was too big, and didn’t work.

So I searched some more online and found this great video where they cut a hole in the roof so you can see what is supposed to happen.

Great. I’ll get a pry bar. I drove back to the hardware store and returned the pipe but they didn’t have any suitable pry bars. So I drove to Harbor Freight and bought a set of three pry bars (might as well have some options.)

Using the pry bar worked a treat. The struts popped right off! I decided that I would initially only install the struts for the glass, since if I installed the hatch struts I’d never get the hinges bolted back on. Installing the struts was a much larger pain in the ass than removing them, but I got them in.

Next I set the hatch into position and bolted the hinges to it. After that I installed the hatch struts – also a huge pain in the ass. I had to prop the hatch up at the fully open position. It would have been easier (and probably safer) to have someone else there to hold it open, but I managed to get it done. I have to say the new struts work great. Not surprising since the springs on the old ones were all busted up.

Struts, old and busted.
Hatch on, struts in.

After the struts were in I ran the wiring harnesses into the hatch and plugged everything in. Then I hooked the battery back up to test and adjust the latch. I had to tweak it a little since it was pulling the door closed too hard, but it worked great. Which is good since once I installed the glass I wouldn’t be able to reach inside and pull the latch manually.

Next was the glass. I put some padding down (bunched up the tarp) to protect the roof, set the glass on it and bolted it to the hinge. Then I installed the two wiring harnesses for the glass. After some adjusting of the hinges I got it to close straight.

Glass installed.

Unfortunately the glass release button wasn’t working. Hrm. It could that the new button is broken, it could be the latch itself. Since the latch came with the new door I grabbed the old one which I knew worked and plugged it in. Still no work. Hrm. At this point I also discovered that the latch for the hatch, which had been working, was no longer fully releasing. WTF?

It’s possible I blew a fuse somewhere while working on the latches.

After poking at it a few minutes I decided that since I was losing my light and the car would close up tight, I would stop and troubleshoot at a later date.

I made some serious progress this weekend and there is no longer a huge hole in the hatch for the rain to come in.

So I guess I’ll keep the car for a while longer.

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