Stephen70

Hi everyone,

Yes - you did read the title right. This is where it starts, a complete 964 Convertible Top Restoration DIY thread.

I haven´t found any threads concerning convertible top replacement for 911-964-993 (maybe there is) so I decided to start my own as I think that Porsche 964 Convertible owners may find it interesting.

As a Finn, my English is not perfect, sorry for that, but I try to explain everything as clearly as I can.

I´m sure some guys think I´m completely crazy and deranged when starting such a project by myself. Anyway, I have quite strong DIY background and lots of experience, so I´m not afraid. I also have some professional support available if needed. I know it will be a painful and time-consuming project. Everything should be ready somewhere early March (or maybe earlier...?)

This is my first Porsche, 964 C2 Cabriolet -92, I bought it about an year and a half ago from the Netherlands. My car was sold in Frankfurt, Germany when new, and imported to the Netherlands somewhere around year 2000. There is approx. 130.000 km in the odometer. Price was very reasonable due to lack of some history records and some other things (some faults incl. bad top). My car has (had) its original convertible top in place, now removed.

My car has experienced this - oh, so typical - electric top mechanism failure in the past due to bad solder joints in control unit, causing left main top bow break-up and some tear in top fabric. The main top bow has been fixed by welding, torn fabric fixed (on left side) and these two 19 mm "magic bolts" opened for manual open-close function. Lock-up remains original (electric).

I have already fixed the control unit, there was some bad solder joints inside causing some lock-up mechanism problems last summer. After the solder fix, both top motors behind the rear seat started to work again.

I have already removed the old top completely, the cab top transmissions are also removed and pulled apart. All the parts are good, so I will use them again. New top incl. headliner has been ordered from Eurotop, Germany, arrived already. I decided to replace the welded main top bow as well (damn expensive!).

Here´s a link to my Skydrive photo sharing website where I add all the pictures when my project goes on. There is already two ugly pictures showing the current status of my car - may look quite shocking!

https://skydrive.live.com/redir?resi...79867720FF!105

Stay tuned!

911Jetta

Welcome Stephen!

Great news that you are a DIYer. This forum loves guys like you!

I have a coupe, but my father has a cab. so I'll let him know about this upcoming DIY. He'll be very happy.

jody stowitts

Stephen70: Would you please elaborate on the 19mm "magic bolts", and with a picture or two. thanx !

Stephen70

Some pictures of transmission parts (and their empty locations) added - as well as one picture of welded main top bow.

https://skydrive.live.com/?cid=e97dd...867720FF%21105

Rocket Rob

Great write up. Keep it coming! And welcome to Rennlist.

Kuchar

Beautiful challenge! Good luck! We all want to be DIYers

Gus

Stephen- you are undertaking quite a job. I did the very same thing about 4 years ago. There are several areas of importance that you need to pay attention to: Bu, first what top are you going to refit - The two sectional 964 top or the 1 piece 993 top??
1. Look at the cables from the drive motors and inspect make sure that they are the proper length and have not become shorter over time do to use. You can modify the ends to fit into the drive unit if they have.
2. When fitting the back window section ( if you do the 2 part roof) make sure that you have moved it far enough forward and up so that you do not have the edge of the top to low where it is exposed when the tonneau cover is on. You might want to mark the tonneau cover position when it is in place and make sure the edge of the roof is above this point.
3. Make sure that you have the frame working properly before you put the roof on . Also this is a good way to make sure the top is good and tight by having the roof raised just a little when you position the roof fabric. When you lower it it will pull the fabric tight and look good. This also goes for the rear window section.
4. Watch the cables on the side window overhead bars and make sure that they are still in good shape or replace. These can be made easily but make sure the back or rear attachment screw is the right kind so you do not puncture or damage the fabric.
Side note - I did not replace the head liner with the stock fabric, but used a foam backed fabric that matched the interior gray of my car. It added to teh looks of the interior and helps to reduce some of the noise.
Good luck on your project - the biggest key is to take your time and make sure everything is aligned properly.

hawk911

watch the hidden nuts for the transmission. Those can snap off the weld easily. I have 1 broken off that I have to fix. Jaime (Wachuko) did a write-up on it using wire hanger and a liquid weld material to basically reverse how the bolt was kept in place.

Stephen70

Thank you very much for your comments and notes Gus,

I´m going to install the original-style 2-piece version, so I will keep your installation notes in mind. I have already checked the cables, left is a bit too short and right is quite much too short. My work order really is to fix, check and align the frame perfectly before fabric work. I think it is much easier now when just working with bare frame. I have ordered new side frame cables, as the left one was almost cut due to some rost.

Stephen70

Two of them missing already...

Stephen70

OK folks, some progress. I have re-assembled both transmissions, they work very well now. I also shortened the cable covers as they were too long for the cables. I have removed the top motors and tested them separately, both are good and work.

Next thing is to install the transmissions, as soon as I have solved the missing hidden nut symptom.

Pictures:

https://skydrive.live.com/#cid=E97DD...867720FF%21105

Happy New Year to everyone!

Stephen70

Checked all the electrics today, seems to be in order. All the functions work as they should. I don't know where I have got some wrong ideas about the possible reasons for main bow break-up. I learned today that faulty motor or control unit can't break anything because these two motors are connected together with small axle between the motors. If one motor breaks, the other should do (or at least try) to do the job... Or blow a fuse. Also, there is only one wire feeding electricity to both motors.

So, if you experience a situation where other side is jammed and other works, the reason has to be mechanical. I think the cable between the transmission and motor unit is the weak link.

Take a piece of rope, pull it tight and start turning the other end. When tension grows, the rope gets shorter... that is exactly what happens to the cable in time.

This leads to the following conclusion: CHECK YOUR CABLES!

Stephen70

Solved the missing hidden nut symptom.

Pictures: https://skydrive.live.com/#cid=E97DD...867720FF%21105

I found some solid blind nuts, drilled a 3 mm thread for small 3 mm Allen bolt - and drilled a 3 mm hole next to the hidden nut hole. I used a long reach magnetic pickup tool to get them nuts to correct places, installed the 3 mm Allen bolt. Installation bolt (M6) for transmission has to be a bit longer to reach new threads correctly.

Rocket Rob

Stephen - My cab's top stopped working this summer. Fortunately, it didn't break anything. I suspect its a fault in the electronic control unit. Do you have any tips for removing the control unit? It looks like its in a very awkward place.

klr10

Hi Stephen,

I have been thinking about doing this job ever since I got my cab four years ago. Last year I replaced the hood on my Mazda MX5 (Miata for those stateside). The guys that supplied the new hood also sold me a DVD which took me through the process step by step. Even though it took me a long time, the DVD was an absolute godsend and I was nipping in and out of the garage to watch the next part of the job.

Have you considered making a video outlining each step? There would definitely be a market for it and you could even recoup some if not all of the costs of the job by offering it for say £10 or so, not to mention the fantastic service you would be providing to us cab owners.

Just a thought, and good luck with the project, the MX5 came out great, and I'm sure I did a more thorough job than taking it to a hood fitting company.

I for one would definitely pay for a DVD.