garrett376

One day while cleaning the inside, I noticed the driver's side vertical support strut (part number 911.561.927.00.70B) had cracked entirely in half. I never noticed when this happened, but I don't think it had been like this for more than a week. Regardless, it needed some fixing. I would like to report on my findings as I go through the process of repairing this apparently common problem with the 964 cabrios.

Last night I set out to repair my ailing convertible top on my 92 C4. Below is a pic of what it looked like as I found it in its broken state.

nine64

good luck!

javascript:smilie('')

garrett376

This has been a great learning experience, as I have no literature to reference - just disassemble and remember! It's quite fun as long as there's no extra hardware!!!

I undid all the connecting arms that attach to the strut that was fractured. I pulled apart all of the 6mm hex screws as seen in the image below...

garrett376

Attached to the strut housing is the weather stripping which was attached with four little 6 or 7mm nuts and some black goop - it pulled off easily.

One note, all the disassembly was performed with the top in the closed position with the transmission motors in the unlocked state by unscrewing the 19mm large bolt on the transmission housing for the arms. The cover was not locked down, so it could be pulled up and down if needed. To get the weather stripping off the top does have to be opened a bit to release the weather stripping from the uppermost portion...

garrett376

The cabrio canvas top is held on to the vertical support with some kind of contact cement adhesive. It pulled off just fine, but sure made the fingers sore. Reminded me of anatomy dissection as I pull and separate the canvas and underlying cloth. This shows the black goop under the weather stripping, and shows the adhesive...

garrett376

Here you can see the entire reflection of the side panel of the convertible top- this does require the removal of the small snap screw that the tonneau cover/boot can attach to. Once it's reflected the 4 hex head screws that attach the support to the chassis can be visualized and accessed...

garrett376

Here are the 4 hex bolts that are now accessible. Two of them are exposed at first - to see the rear two, you have to loosen the lower left one (in the photo) and then you can remove the interior trim panel that is hiding the other two bolts. Unscrew all four of them and the support will come loose...

garrett376

With the vertical strut removed, the remaining fractured part is still attached to the roof. This is the part that's hard! It took an hour or so to get that part removed! Uggh!

That hex bolt needs to be removed before that piece will get loosened...

garrett376

To access this part, the interior trim panel that spans the entire roof portion (when the top's up) needs to be removed by taking out the numerous screws - there around 10 of them. The two that are tucked in behind the support arms are tough to get at - they are easier to access with the top moved to the open position for a moment.

Ok, the reason this part of the job was so hard, was that the remaining piece was attached with 5 rivets!! And, on top of being attached with rivets, there was an adhesive like some sort of epoxy attaching the fractured part to the aluminum crossmember. I was bummed to see that - did I want to drill it out, or what could I do? Well, with my remaining strength, I used some wire cutters and cut the exposed portion of the rivets. It made a mess, but did the job. I was able to cut out all the rivets, and pop out the "head" of the rivet with a nail punch. Once the rivets were out, I used a screw driver to bend the aluminum to crack the bond of the super-duper adhesive. It worked well, although it did alter the shape a bit. I had to do a little bending to get it back in shape.

Then, to further free up that part, you have to undo the three screws on the outside that attach the canvas to the fractured piece...

garrett376

Success - I got the part off!! You can see the green adhesive that made it so hard to get off!!

You can see the delicate headliner ripped while I was "reflecting" it from the fractured piece - fortunately, that rip is tucked where you can't see it...

garrett376

Here's the broken part, and the new part - can you tell which is which??!

garrett376

It's interesting that the fracture occurred across one of the inserted threads... especially since those inserted threads are not used!!!

garrett376

Back to those rivets- the new part from Porsche does not have the holes drilled for the rivets... do I really want to drill holes and make it hard to replace later on??

I decided to drill just one hole to allow the placement of one screw which is on the next post...

garrett376

see the screw that was added - I didn't want to use rivets (don't have a rivet gun, so that helped the decision) so I used a screw instead...

nine64

did u figure it out what cause the part to brake?