Geza

Upon opening the top on a beautiful May Saturday in 2017, shortly after it turned 20, my Boxster top decided to stop and freeze in a half opened position. There goes that ride – back into the garage. After doing a little research, checking fuses, bypassing the top control module, I conclude that the motor finally quit – it has been moving very sloooow the last several years. I pulled off the motor, and ordered a new one; this is where the challenges began.

The new motor came with the proper 3 wires with the pin contacts crimped in place, but no plastic connector body. So, I’ll have to pull the contacts out of the old motor and reuse the connector body. In my business, I am very familiar with contacts, connectors, etc. A contact removal tool is used to compress the retainer spring on the contact to allow it to be unlatched and removed from the plastic connector body. Or course, I didn’t have the tool for this connector, so I tried to research the connector P/N to see if I could buy one – no luck, I tried to make one. I made several, with all kinds of different materials from straws, to more rigid straws (from my daughter’s old sippy cup) to finally, a piece of brass tubing I stumbled upon. I couldn’t get any of them to work – I could not get the contacts out. Time is passing as this is going on - weeks go by from the initial motor removal when I decide to just cut the old motor wires of, and carefully drill out the contacts. This was a last resort as I didn’t want to bugger up the connector body. Works like a charm. So I swap over the connector and motor mounting frame and reinstall, hook up the electrical harness and 2 top transmission cables - finally.

During the initial test, something went terribly wrong. The top (still in the partially open position it died in) starts moving in an erratic manner. Things are not synchronized properly. I’m starting to hear groans and frightening pops. Not good. I shut it down quickly, but not quick enough. Upon examination, I realized I had not properly installed the 2 transmission cables into the new motor – so much time had passed since I removed them that I forgot what they looked like properly installed with their clips (next time take pictures). Now what – I spent hours fiddling with it, trying to get it synchronized, but things were so out of whack – it just wasn’t working out. The service manual mentions using a drill on one cable to drive the transmission separately, which I attempted, but there was not enough cable protruding from the cable jacket to grab hold of with the drill chuck; perhaps some of the pops I heard were sheared drive cables?

Now, a simple motor change becomes ripping apart the entire convertible top mechanism, pulling the cables and the transmissions. Not an easy task. While tearing into the assembly, it became obvious what all those pops were; not only did the driver’s side top plastic ball socket fail, but the bell crank on the transmission broke (see pic). This is a cast iron part! Fortunately, I found a used one online and ordered it, along with new cables and ball sockets. I disassembled the transmissions to check for broken teeth – they were OK and reassembled with the new parts. Using the measurements in the service manual, I adjusted the left and right side mechanisms as best I could and connected the transmission cables to the motor.

Satisfied I triple checked everything, I actuate to mechanism to complete the opening of the top – opens great! Close the top – right before the mechanism normally would stop by itself - POP! I hear a loud noise coming from the passenger side of the mechanism. Something isn’t right. I spend additional time trying to figure out what’s going on, with no luck; finally, I set the problem aside, disheartened. I learned to just let go of the button upon closure before it would normally stop itself – no POP, but I knew it wasn’t right and would once again attempt a fix.

Fast forward a year – I finally mustered up the courage the revisit the top problem. After a detailed review of the top mechanism components in the service manual and after observing the operation of my top, I hypothesized a fix. I concluded that, with the top-closed-micro-switch being in the driver’s side B pillar, and with the POP coming from the passenger side, the driver’s side transmission must be slightly “behind” the passenger side, causing stress in the passenger side, while the driver’s side tries to finish and actuate the B-pillar switch.

Today, I raised the top to the service position and took measurements. Instead of the measurements in the service manual, I took measurements from the pointed edge of the top lid (forward most part) to the top frame, with the tape measure level to the ground (hint: there is a good deal of slop in the lid mechanism – push the lid forward from the middle to get consistent measurements). I was right! The driver’s side was behind the passenger side by 5/16”. I disconnected the driver’s side transmission cable, hooked up a drill and adjusted the Driver’s side so I got the same measurement for both sides, reassembled the cable and closed the top – VICTORY! Closed without a hitch – or a POP! After a year, the final fix took 10 minutes.

Going forward, I’m sure it will take quite some time before I don’t wince when closing the top, it was that traumatic! Hopefully, there is some useful information here for someone else with a failed top motor.

Anker

Glad to hear that! Congratulations.

Byprodriver

Thanks for posting, great contribution!

Brian in Tucson

Nice writeup. If you'd posted a request one of us would have probably given you that piece of linkage. I like having a power top, but for all I had to get thru, not sure it wouldn't have been best to just pull all the trans, motor, and all the linkage and just lower the top manually.

Mine, when the top is up, the clamshell parks properly. Put the top down and the right side parks about an inch higher than the left. All the linkage in mine was FUBAR, one of the cables was stripped, and the right transmission had a stripped plastic gear. In addition the parking brake switch was bad. Done all the work, but still not satisfied. And with all of that wrong, all of the linkage basically destroyed itself.

I think I've figured it all out, I just need to have a "by GOD I'll get it fixed" weekend.

Geza

When my motor failed, I searched here and basically found nothing - which is why I felt compelled to do my write-up. The broken bell crank was only like $10 or so, as I recall, but thanks!

For your situation, I'm thinking the passenger side might be behind the drivers side a bit - opposite of mine. Perhaps take a few measurements. Another issue that I experience while I was fiddling with it is that the clam shell front pivot point would easily pop-out of the slider on the passenger side, especially when the clam shell was not moving "square" due to incorrect synchronization. The more I study this mechanism (I'm a Mech. Eng., who, embarrassingly can't assemble drive cables properly) the more I think I understand it. The B-pillar switch shuts things down upon closure, while the micro-switch at the motor, shuts things down when opening - I believe. Good luck with your resolution.

Several times I cursed Porsche for having a power top! Human nature, I suppose.

Geza

Update. My apologies for the lack of pictures and length (hopefully someone can glean something out of this) – My model is a ’97 with the top closed switch in the B pillar (’97 thru ’99).

Well, it turns out my re-synchronization fix did not work for long – same problem came back. During the 2018 yearend holidays, I decided to attack the problem again. I took apart the left side transmission again to check for broken gear teeth (was fine), replaced a clamshell push rod (the original looked like some paint was scraped off, so I thought it might be bent. Buttoned everything up - problem persisted. Fast forward a few month to May.

This time, I decided to remove the clamshell altogether, so I could observe each hinge mechanism individually. Turns out the clamshell was twisted – when placed on a flat surface, one pointed end was elevated ~1 inch above the surface. Holding the clamshell vertically and in place with my feet, I carefully twisted the other end in multiple stages to straighten it out, and set it aside.

With the top lever arms disconnected from the transmission (via the eccentric bolt), I used a drill on each drive cable to position each hinge in the stowed position (with the same bit of looseness both sides). Both transmissions were now properly synchronized and in the top closed position. I reassembled to cables to the motor, where they would remain for the rest of the project.

Next step was to observe the operation of each hinge mechanism. With the top closed/latched, I reattached the top lever arms to the transmission after first loosening the center adjusting screw (that holds the 2 parts of the lever arm together). So now the top is closed and the transmissions are in the closed position as previously set via the hinges. I tightened the center screws (adjustment didn’t really change) on the top lever arms.

To check the operation of the hinges, I removed the push rods, which allows the hinges to fully articulate. I found that, with the top in the closed position, the left side hinge was making significant contact to the left top lever arm when the hinge moved towards the closed position. Enough contact that the paint was worn off the hinge and that the hinge was applying pressure on the lever arm when stowed. The right side hinge made no contact to its top lever arm, but got pretty close.

I pulled off both hinge assemblies and compared them by eye – it looked like one (left one, I assume) was slightly twisted at the front, where the ball connection to the slider is. I thought of buying a replacement but decided to see if I can get the original to work.
Being a die cast aluminum part, I was concerned that trying to twist it back would cause it to break, so I set that idea aside. Turns out, to Porsche’s credit, the slider ball end is mounted to the hinge via an eccentric, which allows for some adjustment. So, I loosened the eccentric ball on both hinges, reassembled and adjusted them so they would clear the top lever arms as the hinges closed. The right side didn’t require much adjustment. The left side, fully adjusted to provide the most clearance, was still rubbing against the lever arm (because it was twisted). I decided, since the paint was already scraped off the hinge, to take a file to the hinge in that area and smooth it out so it no longer made contact. This didn’t take much material removal, and the left hinge now articulated without contact.

While fiddle around with the clamshell pushrods, I noticed the bushing where the pushrod attaches to the hinge was missing on the right side hinge; this made the hinge/pushrod action sloppy. These don’t appear to be available, so I ended up making an insert from sheet aluminum (gutter flashing) to act as a round bushing ring between the hole in the hinge and the pin on the pushrod. I’ll keep an eye on it for wear, etc. Seemed to work at removing the slop. At this point, I pretty confident I have all the motion issues sorted, so I bolted the clamshell back on.

My next step was to sort out the electronics, to verify they were working properly, shutting down when they are supposed to, etc. After several iterations of testing the electrical operation, switch continuity for the clamshell and B pillar switches, and misdiagnosing a bad top controller (which I ordered and now have as a spare - $200 later), this is how I would suggest testing the top is working electrically (assuming a working motor). You will need an assistant

To test for proper opening: open the top to the service position and stop. Now, have the assistant continue to open the top (dash switch); while in motion, you depress the clamshell switch (above the motor). This should stop the opening function, but not right away. There is a delay of maybe ½ sec, between the time the switch is pressed and the motor stops. This is why I suggest you activate the switch – to see this delay, which is built into the controller. If the top stops after the delay, the opening function in the controller is good, as is the clamshell switch. If not, one is bad and further trouble shooting will be required.

To test for proper closing: with the top in the service position, disconnect the top from the transmissions by either unbolting both top lever arms or disconnecting the plastic ball sockets (I found unbolting easier). Close the top manually, but do not latch. Now, have the assistant close the top via the dash switch and you activate the clamshell switch. This should stop the closing operation after a similar ½ sec. delay. If it does, the electronics, including the B pillar switch, are working properly. If not, one is bad and further trouble shooting will be required.

I did all this and my top appeared to be operating correctly, shutting off when it is supposed to, when both opening and closing. Then, on one really hot day, when closing the top, I sensed something wasn’t right. While closing it, although it stopped on its own, it just seemed like the clamshell switch (which shuts down the motor in both directions, after the built in delay) seemed to activate a little late. The next time I tried to open the top, it was locked shut, as if the transmissions were jammed. I think the switch indeed activated a little late allowing the motor to tension up the mechanism more than it should. The mechanism was kind of jammed.

To get in open, I accessed the motor from inside the car, disconnected both cables from the motor, open both transmissions a hair (using a drill) to relieve the tension on the clamshell pushrods and, using a flat screwdriver, disconnect the ball end connection between the push rods and transmission. This allowed me to manually open the clamshell for access.
Everything seemed in order – I think what happened is the clamshell switch, which is mounted to the motor assembly and was removed when I replaced the motor, was not quite in the proper position (sitting a bit lower than it should). It was being activated by the clamshell a bit too late in the closing process. So, I determined the location where the switch contacts the clam shell (paint was a bit worn at the contact point), and, using some thin rubber double sided tape and a thin piece of aluminum (same gutter flashing), built up a pad (about 0.080” thick) which causes contact with the switch a bit earlier. Everything seems to operate now. I was thinking about loosening the motor and moving it (along with the switch) upward, closer to the clamshell – perhaps in the future. For now, everything seems to be working properly, though I still wince when I close it.

Since I bought a new controller, I took apart the old one, which I ultimately reused – since nothing was wrong with it. It’s more sophisticated that I thought – with the built in delays and all. Here’s a picture of it.