jrb964

In 1991 one of the first problems I had with my 964 was that the major support bracket for the cab top snapped in two. It was the one on the driver side and it was directly opposite my ear. It sounded like a gun shot. It tore the top and messed up a number of items. Needless to say it was expensive. I believe I posted to Rennlist my saga and cost.

About a month a ago I was trying to remove the top and it made awful sounds, and I've learned that "awful" sounds are not good and are usually expensive. So I stopped immediately, analyzed the situation and found that the driver side support arm was broken, the weld had not held. I managed to get the top secured down and you could not notice that it was broken.

Last week I took it to my mechanic, this job is too big for me, and he ordered a new support arm and begin to analyze the problem. Upon getting a look at the problem he determined that one of the motors and its mechanism had failed causing excess stress on the arm and thus the failure in its weakest point. He further went over all of the weak points and why they fail on a regular basis. It's not will it fail but when. There are only so many times that the top will go up and down before something breaks; and its usually costly.

I was quoted the price for two new motors and nearly passed out; and jokingly said,"...wished I could convert it to a manual top...". My mechanic said that real easy, it will not be totally manual,but semi-automatic.

The support arm was replaced, the motors that closed and opened the top are gone, and the switch on the dash unlocks and locks the latches. To remove the top I actuate the switch that unlocks the latches. After the latches are open I always unzip my rear window and lay it down so as not to fold or bend it in the middle. The top is grasped at the front center and moved back, at the apex of the arc it tends to want to go down rather swiftly. It takes less time than doing it fully automatic.

The only item that is not addressed is when the top is down the red light on the dash is on.

The nice part is not more cab top problems.

Adrian

Dear JRB,
There are microswitches on the two transmission assemblies which are the position UP or DOWN microswitches. It may well be that they are not making when you manually lower the top.
Ciao,
Adrian
964C4

Ruairidh

Thanks for this

I'm going to do this conversion (or rather have it done for me). The advantage of not having to worry about the thing $topping working far outweighs the utility of the power operation to me).

So Adrian, are you saying that if the microswitches make contact when you lower the top the warning light won't come on?

Jrb964, am I right in thinking that when you raise the hood you pull it up to the latches on the front windshield and then actuate the switch and the latches do the rest?

jrb964

Ruairidh, yes you remove the boot (if you use one) and then just lift the top, re-zip the rear window, and activate the switch to latch the top.

That's it. Less time than the automatic.

ian c - u.k

hi !!!

i need some parts to convert my manual top to electric !!
do you have parts for sale ??

i need to things that go behind the side covers in the rear seat area , and the wires that go from them back to the motor .

hope you can help

thank you
ian

Adrian

Dear Ruairidh,
The are 4 microswitches involved with the roof. One each for the locks and one each for left and right side mechanisms. It is called switch logic. The position of one and the position of another open or closed tell the system that the roof is up or down.
Roof up the latches microswitches confirm roof is up (closed) and the transmission microswitches confirm the roof is not down (open). For the roof down the latch microswiches are open and the transmission microswitches closed. If either combination is not met the warn lamp is on. Simple really.
Ciao,
Adrian
964C4

Ruairidh

As ever, many thanks Adrian and thanks too to Jrb.

Ian, my plan was to disconnect but not necessarily uninstall at this time - sorry.

America

If you want the semi-manual top all you have to do is loosen the two large bolts underneath the plastic cap. The locking mechanisms will still work as long as the two sensors are aligned. I had the top semi-manual for about a year.

Rory H.

Since we are talking about Cab tops I have a minor problem with mine. When I am closing the top and hits the edge of the windshield the locking mechanism does not activate about a quarter of the time. Then I reopen just a little and re-close and it will activate, at the most, I have to do this a couple of times. Like I said before, 3/4 of the time it works fine the first time.

Any Ideas?

Thanks,

1990 C4

Rory

America

Rory H.-this is a common problem for the top. The problem is usually mis alignment of the top. The two sensors or buttons on the locking mechanisms are not being depress during the closing process. The top just need re-alignment. I believe its a easy fix but I never fixed this problem myself. To test my dianosis all you need to do is the next time the top does not close, stick a flat head screwdriver into one or both of the the buttons. If it closes its mis-aligned. If not, there might be a problem with the locking mechanisms or electrical problem. Good luck!

Rob McConnell

Hi

The microswitches being discussed are on the gear packs behind the rear speakers. They can be adjusted using a screwdriver.

They tell the motors when to start and stop driving the hood.

So when you lower the hood the microswitch comes in contact with the arm if my memory serves me correctly and closing this circuit tell the motors to stop lowering the hood. It is the same in the closing operation, the motors are told by the switches to stop when the hodd comes down on the windscreen, then the latches can begin to work.

Cheers
Rob 91 964 cab (still working touch wood)
Jersey/UK

Herbie

This automatic --> semiautomatic procedure isn't 100% correct.

Manual cabrios have a latch to keep down capote, when open, avoiding bounces in bad roads.

In automatic cabrios capote is kept down by locked motors.

Herbie

But, if converted in manual, a manual latch has to be added.