I know many folks here have given up on ever getting their cabriolet tops to work properly and have gone to 'Manual operation' as a result. They are complicated and if not operated and maintained properly can become inoperable. When I bought my cab this past July, the only 'ding' on the PPI was the top operation, it opened and closed o.k., but seemed to 'freefall' from about halfway open or halfway shut and you had to catch it with your hand or it would slam down onto the top of the windshield frame. Not good.

Well, I'm happy to say that I 'discovered' the guy that Porsche Cars North America trained on the west coast to be the trainer for all the other dealership techs that were selected to learn to repair the 993 power top and he was right under my nose, at S-Car-Go in San Rafael http://scargoracing.ypguides.net/ where I had the PSS10 suspension done on my coupe. His name is Pat Sexton and he's a Porsche certified Master Mechanic that spent most of his career as the Lead Service Tech at Sonnen Porsche in Marin. Nice guy, pure craftsman.

So, when I described my 'problem' to Pat, he immediately said either one or both of my motors were loose and/or disconnected causing the 'gap' in tension during operation. He also said that when the top system is adjusted and timed properly that it should work perfectly for years and years with a minimum of maintenance and that most owners never read their operation manuals or the following TSB's that Porsche released on the tops and their proper care and operation which has caused many of the problems. He also said that he had to study and work on several top systems to get to the point where he could get them aligned/adjusted and most importantly, all the switches and motors 'timed' together properly so the tops worked correctly but after they are adjusted properly they should work flawlessly with a minimum of maintenance, for years.

As soon as he inspected the system, it was apparent that someone had tried to 'fix' the top in the past and had disconnected the drivers side motor as a result, leaving the passenger side to do all the work. It was never apparant why this was done because everything seemed intact. Luckily, it hadn't been that way long so no damage to the carriage mounting points or gear transmissions had been done, however, both drive cables were worn (they constrict over time, not stretch ...big surprise) and the elastic tension straps on both sides had been damaged because the original factory installation of the straps causes them to get caught between the aligning pins on the frame and the slot the pins nest in, which is documented in a TSB.

Pat also said that many cabriolets top assemblies are bent/damaged because the rear bulkhead panels were welded in out of tolerance at the factory and cause the top assembly to compress as it folds down and there's also a TSB that covers that repair. The panel actually has to be "reformed" slightly to allow the top assembly proper clearance. Fortunately, my car, being a '98 and late production it didn't have that problem, but it seems like Porsche should repair cars that do. That might be part of recall number A502 that replaced the front locking motors and did a complete 'service' on the top and it's components.

So, after everything was taken apart, cleaned, lubed, checked for damage/function, reassembled with new cables, re-installed, adjusted and all the motors and sensors re-timed to work flawlessly together in synchronized harmony (which he said was 'The Black Magic' that is needed to get the top to align and work perfectly without causing damage to the assembly or needing any manual assistance) I'm happy to report that my top opens and closes perfectly and quietly, like a swiss watch, just like it was designed to do.

Total time: 3 hours at the hands of a Master. Total cost, parts, labor and tax: $1033.67. To be honest, that seems reasonable to me considering the result. The parts weren't cheap at $270/each cable and $80/each for the two straps, and, interestingly, it seems they are not pictured in the PET. Luckily, S-Car-Go had the NOS straps on the shelf from years ago and they were able to get cables delivered in an hour.

 

I'm in Sonoma so San Rafael is a quick trip for me. My top seems to work fine however the previous owner stated that the cables were replaced twice. The only problem (I'm aware of) now is on the passenger side, the door cannot be shut with the window rolled all the way up-it hits the weather seal at the very front of the window next to the wing window. Looking at the top/windscreen connection, the top sits down slightly lower on the passenger side than the driver's side when shut.

I may pay S Car Go a visit,

Thanks,

D.

 

Yep, that sounds like a job for Pat. The side windows on both my '87 cab and the '98 catch the tops longitudinal seal just slightly at the rear upper edge of the glass if you shut the door with the window rolled all the way up, but I think that's by design to get a weathertight/windtight seal, I don't think there should be any interference at the front edges by the windwing. I always push the rear upper corner of the glass with my thumb as I'm closing the door from the outside to relieve the stress and I always try to remember to roll the side window down a smidge when I shut the doors from inside the car. What can I say, my background is engineering...

 

I thought later cabs (late 95 and on) have only one motor. Regardless, I can't see how the whole top can be raised (to close) with just one side cable works. When that happens, the whole top will twist as I've seen it did to my my top. But mine is an early 95 with 2 motors so may be it operates differently.

 

Actually, I think they all have the same system, and yes, I believe your correct there is one motor at the back and a transmission and cable at each side. It was the transmission on the drivers side that was disconnected. And yes, it was a real surprise for me to see that only one side was actually doing most of the work once he removed both side panels and the rear shelf cover. The top really did open and close fairly well and once it was 'caught' with your hand at the windshield it aligned perfectly and closed tight. It was just the entire movement between closed and open when the front frame weight crossed the line from being pulled or pushed to 'free falling' that was completely out of control. Glad it's repaired correctly and working like new, it could have been much worse and much more expensive.