Power Top Motor Failures

A broken motor is a common problem with the E30 power top. Until recently, if your power top motor broke you only had two choices, to replace the broken motor ($500-600) or convert to a manual top.


This appears to be the most common failure. Christian, in Germany, is selling a reinforcement that is designed to prevent this type of failure. Rob, from the E30ic list, had one shipped from Germany and was very impressed. You can find some pictures of the reinforcement on Christian's website, at http://www.ib-ideenbau.de/E-30-Seite-2.40446.html . John installed the reinforcement on his broken top motor and documented the procedure on his website.
Another company has started making a repair plate - http://www.automac.co.uk/product/E30%20H%20mtr

Realignment Procedure

If your power top is raised/lowered manually or your top motor is disconnected, the top must be realigned before it can be normally operated again. I've heard that dealers normally charge $500+ to do this. This procedure to realign the power top was posted to the e30cabrio list several years ago by Greg (original post).
Top motor re-sync procedure>>

To the left of the motor that controls the top (far right motor) there is a black control box that has (4) relays (coils). Check these (4) coils with a 12v tester for power with the ignition key on. If all of these have power then it is possible to get power to the micro switches. If these relays do not have power, then you'll need to either swap out the control box or troubleshoot the wire harness by doing some continuity checks.

The reason the top does not work is because there is no power to the micro-switches, I'll explain.

Power to the micro-switches is controlled by the lid motor lock mechanism. The lock mechanism is controlled manually by the allen wrench. When the lid is locked and the lid motor engaged the switches will have power (you'll notice that when you lock the lid, the lid motor assembly swings in and out slightly). When the lid is locked it swings the motor closer to the body of the car and completes the ground for the micro switch. The problem is, it is very difficult to get both the lid locked and the lid motor engaged. They must be done simultaneously. If you have power to the relays, here is how to get power to the micro-switches.

This is easier with two people....also make sure the ignition key is on

Disengage all the motors (unlock the lid mechanism, disengage the lid motor and the top motor)

Undue your top from the front window and push it up like your going to put the top down with the switch

These have to been done in this order.

Re-engage the top motor (far right) have someone slowly lift the back window until you can seat the top motor in.

Now the hard part...

You have to lock the lid mechanism with the allen wrench and engage the lid motor at the same time. It took me several tries at this. Try locking the lid half way, then pushing in the motor half way and play with it until the motor pops in and the lid locks at the same time.

If you were successful you can turn the micro switch adjustment screw (located to the left of the allen lid lock point). When you turn the adjustment screw you'll hear a click when the switch turns on or off, you'll have to listen carefully. If you don't hear a click then you have to disengage the lid motor and unlock and try again. If you do hear clicks while turning the adjustment screw, turn the screw all the way to the left and slowly turn to the right until you hear a click. Then test your top, does it work? If not turn the screw all the way to the right and slowly turn to the left until you hear a click. Then test your top again, it should work and may require further adjustment using this adjustment screw.

This is a difficult procedure to explain, but it is fairly easy to do yourself. The micro-switch will not get power if you are unable to lock the lid and engage the lid motor simultaneously. My dealer could not even do it. So it will take some playing around with until you get the feel for it. Once all the motors are engaged and there is power to the micro switches you just have to turn the lid micro switch to the position the tells the system the lid is down and locked. Then the top should operate normally.

Another Top Repair, with hints

Michael posted a message to the e30ic mailing list, after successfully repairing his power top. He used the repair kit from Christian and included several other good peices of information. Here's his message:

Well, after a year or so of tinkering, pondering and doing research on the net, I finally bit the bullet and reconnected my power top. And by god (furiously knocks on nearby oak table) it seems to be working just fine. I thought I would share a few of my experiences with you guys, considering how much help I've gotten from this group and elsewhere.

If you have any doubts about the condition of your top motor casing, I can't stress enough how nice the motor repair kit from ideenbau in Germany is. It's very well made, not that difficult to install, and really should alleviate problems down the road. I know its installation is well detailed on e30ic.com.

Definitely replace both of the top shocks (and their carriers as the dimension of the shock body has been enlarged just enough that the new shocks wont fit). If you're familiar with realoem.com, they are numbers 3 and 4 in the folding top section, or BMW p/ns 54 31 1 932 751 and 54 31 1 943 751. Even though my top is original and the tension straps kinda saggy, the top generally has no trouble going up or down properly, and you can definitely feel the shocks helping to push the frame back up.

Make sure the top frame is very well cleaned and lubricated at all pivot points. When I was operating my top manually the difference in ease of operation before and after the lube job was tremendous. I used carb cleaner (very carefully) with a big rag to catch over spray and then went back with Wurth spray lubricant.

There is a modified motor cover, p/n 51 71 4 376 227 which was introduced after customers complained of marks on the window and right side of the top--see TSB 54 02 93. It's made out of the same sort of material as the trunk linings and has a much lower profile. It's still available, and thankfully isn't too expensive--$25 or so.

If you can get a hold of the instructions for retrofitting the power top, it is well worth it. I found a copy on ebay.de (Einbauanleiting fur EM-Verdeck) which is really a stretch for my limited deutsch, but it's very nicely illustrated, shows where every component is located and has detailed measurements for adjusting the linkages, motor arms and microswitches. Unfortunately there are some dealer only tools involved in the adjustments, including an $85 gauge for setting the top motor switches, but it is possible to eyeball things based on the pictures. Some of this information is the same as what's included in the manual posted here by Hakan, but I think there is a little more detail overall.

Well, that's all I can think of off the top of my head. I am definitely not an expert, but if anyone has any questions or comments about the power tops, I know I have spent way too much time doing research on them and would be happy to put my '02 cents in.

Happy topless driving,

Michael