Goughary

Unfortunately - i didn't make a madness thread for the cab I've been working on for the past four months. I've done literally hundreds of little fixes.



That's the car. 92 cab. 78k Miles. Nice car, but the current owner has lived with it for 18 years, bought from the original owner, and has only fixed the things that needed to be fixed over the years, which meant that all the little stuff was left languishing, waiting patiently for my arrival.

So we did, like i said, hundreds of things- too many to list here really...but currently, it's a really good car, and almost fully sorted. Getting there.

But let's talk about convertible tops- cuz i knew next to nothing about the convertible tops when i started...just never had to fix one.

When you look for threads on the convertible top issues- there is virtually zero information. And i may not be much better here, as i have taken limited photos.

There are a couple of good YouTube videos on testing the top function however, which can be helpful in figuring out where the issue is in the top.

Anyone who happens to be a convertible top expert- please correct anything i say here that is incorrect.

For the top to function - there are a bunch of things - stars really - that need to align. And if the pagan convertible gods are on your side, the top will move when commanded.

First. The car has to be off, with the parking brake on, then turn the key two clicks to "on" without starting the car. Then push the button, hold until the top is all the way down. And whalla! Top is down.

To put the top up- same thing, but push the button the other direction, and after the horrendous crash of the top hitting the upper window frame, and the raunchy mechanical latches wrenching the top into place with tremendous force....top is up and you are now able to stay "sorta dry" should it be raining.

Goughary

That first post was easy.

Now - In my case, the pagan convertible gods were not happy with me. I once looked upon the wrong woman...of something of that nature. And they have decided, in unison, to make me pay for such a terrible sin...and it wasn't even a neighbors wife...which they probably don't care about anyway, cuz they are pagans and know nothing of such things.

There is a fuse. This must not be blown.
There is a control unit under the driver side dash, hidden under the control unit that manages the dash, all of which is behind a sticky mess of wrapped wiring harnesses.
There are main motors, behind the rear seats. I know nothing about them, other than they are strong enough to break the roof.
There are latch motors.
There are micro switches. Some that you can easily see, and some that you can't. There is one to make the top stop moving back when lowering the top. This is inside the right rear quarter panel. Above and to the left of that one, there is one that never gets clicked. It's purpose is to stop the roof if it travels too far forward. So it's set so that the roof stops just prior to clicking it.
There are then, two more micro switches on the front of the roof, that once clicked, tell the motors to stop moving forward, and then the control box begins to work the latch motors instead. And then- the hidden micro switches inside the latch motors. These are likely the ones no one ever gets to before abandoning the mechanical roof and converting to manual function.

All of those things have to be set and working properly and at the right sequence in order for the top to function.

I didn't mention the adjusters for the roof. They move the roof up and down, and forward and backward - to align the front roof pins so they meet the holes at the top of the windshield. When i was first trying to get this roof to work- it had intermittent function- but what was clear then, was the roof was horrendously out of alignment- so i did the alignment first- and had to use the "call a friend" option. So me being me, i called two. And after a bunch of frustration, finally got the adjusters to move. I was doing wheat i was supposed to be doing, but the roof wasn't moving because the adjusters has never been used since new and were stuck. Eventually- with a BANG - they popped lose and from there, adjustment was easy.

Part three next....

Goughary

So once the roof was adjusted. It worked for a little bit. Then it didn't, then it did. And then it didn't. It was driving me crazy. It seemed so erratic - just the kind of thing that would drive a guy completely...mad...

I am getting to the point here...it's coming.

So eventually - i figured out how to make the top not work.
Once working, all i had to do was start the car, and the top would stop working. But yet, sometimes it would be working, and stop halfway closed or open. Or go dead when down or dead when closed.

Control unit. But you can't buy a control unit from Porsche. They are out of stock. So i bought a rebuilt unit from ECU repair. They are great. Unit came quickly and it's warranted. So happy there. But that didn't entirely fix the top. But it did change the sequence of failing a little, so it did fix something. But the top still didn't work.

I had gone through everything, all the micro switches - except for the ones inside the latch motors....get this- latch motors commonly fail, and Porsche doesn't sell the parts to fix them, of course...so you have to buy an entire motor/latch assembly for 1700 dollars...uhhhhhm...Porsche fail.
Uro parts, however, makes a gear kit for the latch motors, and those gears are the common failure, and they cost 80 per set.




So let's go back to the latch motors.
To test- rape down the little wheels on the front of the roof - which tells the control unit that the top needs to be latched - and it then runs the latch motors. Both latch motors should run in tandem, to full closed position. In my case, the latch motors wouldn't run at all. This...would be a problem.

I noticed one of the latches was different than the other. It had a little too much play in it.





So i took that one out.



More coming...

Goughary

So i took that motor apart to see what was going on....











So look at that! Broken gear. Uro parts to the rescue...

Imagine now that one week has passed...as i was waiting for the parts to arrive...tick tock...

Goughary

Ok. One week has passed (virtual world)...

Here is what it looks like apart...



And then, what you need to do, is grease the gizamherm and press the gear onto the shaft, and then install the cam (looks like my aluminum WOT switch hat) onto the shaft as well, and screw that down. I pressed it in a vice using a 1/2 drive socket as a press tool. Do not over tighten this. The motors shut off - aka stop working) if they hit the end of a cycle, and therefore of the gizamaherm can't move, the control box stops the latches and the top. Should have mentioned that in the post above, as this is yet another star that needs to have aligned...





Now. When you go to "clock" the gear to the shaft, and then subsequently adjust the cam gear- here is the important thing- which apparently no one knows...or at least - the dude that knows, has not stated it in a thread that i have yet to find...

Most of the time one would have to perform this service, is that the gear breaks, as has mine- so in my case, only the cam was flopping around- which caused the intermittent function, but often the gear rotates on the shaft, and therefore you wouldn't know what the orientation should be, unless you have one vital bit of information...that the cam has to click the microswitch at full open and also at full closed. So when you reattach the microswitch to the side with this gear, rotate the gizamherm around fully one way, and the switch should click, then all the way around to the other side and the switch should click.

Finish greasing everything and reassemble the case.

The case by the way. Has four screws holding it together. Take them out. And carefully pry apart the halves. They are indexed with two small rollpins, so with careful prying it just comes apart, and then with some wiggling, they go back together.



And done...

So as long as the rest of the system has checked out- which is easy since it's all out in the open - once you have these functioning correctly, you should have a fully functioning top.

Yes- there are more things that could be the issue...but in my case, the one latch motor caused the rest to go onto tilt. Thankfully we replaced the control unit, so my hope is, I'll never have to see the insides of this top ever again... it was waaaaaaaay too much work, too many hours of research, and too difficult to figure out, never having done this before.

But now that the idea of owning a cab is growing on me, i may look for a deal on a cab with a bad roof.

So there you go. If this helps one cab owner to not turn his cab top to manual function. I've done my job, and hopefully satisfied at least one of the pagan gods who isn't too pissed at me...cuz it's spring. And there is a lot to look at.

Ralph3.

Good stuff, nothing like a few years of deferred maintenance. Thanks for the write up, hopefully I won't need it in the future.

jfig

Hi, did you say your 92 Cab has rear seats? Haven't found too many of those after 91...

Goughary

It has rear seats yes. But it's not my car. It belongs to someone I've never met. He found me through a fellow rennlister, and after agreeing to "the rules", shipped it to me.

At that time, it had been in a shop, for half a year, not running. The shop couldn't figure it out. I had it running and out on the road in two hours of scratching my head and ten minutes of work. It needed a battery and a dme relay. Lol.

But, when i see these cars, the list grows in my head...so he wanted to tackle the list, and here we are four months later waiting for a set of Campy Sport wheels from augment wheels...it now has a fresh suspension and hundreds of little and not so little things fixed and sorted. As t sits, it's now a really good car...

jfig

Amazing story! Where are you located? Do you know of it came from the factory with the rear seats or someone put them in after market?

i’m close to buying my first Porsche (92 Cab). I wish you where in upstate NY, would give me piece of mind LOL!
Jonas

Lorenfb

Actually, it's not that difficult. Read here http://www.systemsc.com/problems.htm
under Porsche - Cab Top

DeanL

Great story and description of how these tops work and don't work. I just had a rebuilt controller installed in my '92 Cab. I had the same, "cross your fingers and push the button for up or down" that you described. I would pull the fuse and relay and sometimes movement happened, then nothing....
The new rebuilt controller and fiddly tweaking of the micro switches brought the top back to life. Still cross my fingers and push the button but happy with workings so far.

Thanks again and enjoy your Cab--great cars!

Goughary

Yep. Exaggerating as usual. It all seemed very complicated until i figured it out. And now it seems a relatively simple system. But you know how these things go...thanks for the link!

Rocket Rob

Congrats on fixing the problem. I had to repair one of my car's roof latching motors this past winter. It was intimidating at first but in the end not too hard nor expensive.

Marine Blue

Nice to see the procedure and explanation. One of the reasons I tend to stay away from convertibles is because I’m intimidated by their tops and the cost to repair them. Seeing posts like this helps realize that they aren’t always overly complicated and ownership and repairing without spending tons of money is possible.

The little things, when combined with an already nice paint/interior are what make a car truly great.

BHMav8r

One side of my top stopped working - thinking of just going manual.
Easy peazy.