Clamshell won't close the last two inches

[jamesanderson84]

2000 C4 Cab. I've owned the car for three months and have had no issues with the convertible top operation. Yesterday I went to open it and everything worked fine - except the clamshell won't close the last two inches onto the deck. There does not appear to be anything physically in the way - there are no odd noises or grinding - it just stops.

I can close the top again without problem and the clamshell closes properly when the hood is going into the closed position.

I've searched the forums and I can't find anybody describing this problem exactly.

I've read the posts about topping up the hydraulic fluid - and based on car age this is a candidate - but I read in one post that the clamshell is driven by a motor not by the hydraulic pump anyway.

Would appreciate any pointers - this feels like something very stupid or easy to fix - so obvious advice is welcome.

[iornman86]

2000 C4 Cab. I've owned the car for three months and have had no issues with the convertible top operation. Yesterday I went to open it and everything worked fine - except the clamshell won't close the last two inches onto the deck. There does not appear to be anything physically in the way - there are no odd noises or grinding - it just stops.

I can close the top again without problem and the clamshell closes properly when the hood is going into the closed position.

I've searched the forums and I can't find anybody describing this problem exactly.

I've read the posts about topping up the hydraulic fluid - and based on car age this is a candidate - but I read in one post that the clamshell is driven by a motor not by the hydraulic pump anyway.

Would appreciate any pointers - this feels like something very stupid or easy to fix - so obvious advice is welcome.

the claim shell is driven by a motor and wires, it has a variable resistor on the unit that tells it the motors current position. if the variable resist or develops a dead spot it may cause issues. i replaced my claim shell motor and had issues with it because i didn't set the variable resistor correctly. just a wild guess.....

[JeTexas]

Are you sure the cloth from the top isn't lying over the latch when the top is down? There should be a springloaded piece of plastic that sticks up from the latch cover to stop the top from getting into the latch, but it often breaks off and disappears. That's the first thing I'd check.

If there's nothing blocking it, and the top's not on the latch, the fact that the clamshell will close with the top up tells me that the clamshell mechanism is working correctly and can reach it's open and closed points. Therefore the fault must lie in either the convertible top or possibly the little wing flaps on the sides not reaching the points they're supposed to reach. All the position sensors are interdependent, so if one mechanism doesn't reach it's end point, it stops the other from working.

Actually, I'd bet money that if you check again, you'll notice one of the little wings isn't in the closed position. You probably just need to remove the panel behind the back seat grease the screw drive that it moves on.

[jamesanderson84]

Are you sure the cloth from the top isn't lying over the latch when the top is down? There should be a springloaded piece of plastic that sticks up from the latch cover to stop the top from getting into the latch, but it often breaks off and disappears. That's the first thing I'd check.

If there's nothing blocking it, and the top's not on the latch, the fact that the clamshell will close with the top up tells me that the clamshell mechanism is working correctly and can reach it's open and closed points. Therefore the fault must lie in either the convertible top or possibly the little wing flaps on the sides not reaching the points they're supposed to reach. All the position sensors are interdependent, so if one mechanism doesn't reach it's end point, it stops the other from working.

Actually, I'd bet money that if you check again, you'll notice one of the little wings isn't in the closed position. You probably just need to remove the panel behind the back seat grease the screw drive that it moves on.

The plastic latch cover is present and flips up when the hood is closing - so I dont think its that.

I agree that it might be one of the little flaps on the hood mechanisms - its not clear what position they should be in as the hood closes - does anyone have a picture of the right positions? I'm concerned if I start playing with them I could do more damage than help.

[JeTexas]

The two side flaps should be completely closed (parallel to the ground) and look flush with the rear deck before the clamshell will finish closing.

If they're open and pointing to the sky, they're not in the right position.

I don't have photos here at work, but it shoud be explanatory when you look at it.

You can manually spin the motor to move them in position with an allen wrench (it might be torx, but I think it was an allen wrench). The top of the screw drive with the allen head is accessed through the holes where the feet of the hardtop fit. There's instructions for this in the users manual.

[jamesanderson84]

Well - more fun last night trying to resolve this problem.

When I opened the top the same problem happened - stopped about two inches away from being complete.

I found that the plastic shield that is connected to the rearmost strut on the driver's side and carries a wire had become disconnected from the strut - but reattaching the plastic shield made no difference.

I looked at all the little wings and flaps and they all look fine, i.e., the left and right sides are in the same position, and there is nothing obviously fouling the clamshell.

I joggled the clamshell a little and did manage to get it to close - but only once. I'm nervous about too much joggling seeing so interconnected this whole system is.

So...I'm now thinking that some mechanical resistance has developed that the clamshell motor is not able to overcome - but this does not seem to jibe with the fact that the clamshell closes fine when going into the "roof closed" position.

[JeTexas]

I don't think so. If the potentiometer is working correctly and the motor is working correctly when the top is closed then those things would not work any differently with the top open. However, you could have a sensor somewhere saying the top isn't open, the latch isn't open, the flaps aren't up, etc. That would then stop the clamshell from closing all the way.

If you hook it to a PST2 or a Durametric, it can talk to the convertible top control unit and tell you what each compoment is saying/doing.

When you jiggled the clamshell, did it fall shut or did the motor close it the rest of the way? They can be pushed closed, but the lock won't actuate.

[jamesanderson84]

I don't think so. If the potentiometer is working correctly and the motor is working correctly when the top is closed then those things would not work any differently with the top open. However, you could have a sensor somewhere saying the top isn't open, the latch isn't open, the flaps aren't up, etc. That would then stop the clamshell from closing all the way.

If you hook it to a PST2 or a Durametric, it can talk to the convertible top control unit and tell you what each compoment is saying/doing.

When you jiggled the clamshell, did it fall shut or did the motor close it the rest of the way? They can be pushed closed, but the lock won't actuate.

The motor closed it the rest of the way - but it did not "feel right" - it seemed like there was still some resistance.

[jamesanderson84]

Just to close this thread (at least for now) - after I made these posts the top started working fine again - closing the last 2 inches without trouble - so the mystery remains as to what was wrong - but it fixed itself so I've stopped trying to solve the mystery....

[Gregory Chronowski]

So I've got the same problem, described identically as above.  I'm thinking that it is the number 7 microswitch seen in the image below.  Thinking the cover isn't sensing that the top is fully closed...

 

Would appreciate any others who may have some ideas.

 

 

Full link to the above post is at: 

Convertible top not in limit position - Rennlist - Porsche Discussion Forums

RENNLIST.COM

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997 Forum - Convertible top not in limit position - Convertible top not in limit position We know that this is an issue on 997 cabs, and I've had sporadic issues with this message popping up when I put my top down. The top works fine but when down, the message would occasionally...

 

Edited September 30, 2020 by Gregory Chronowski

[Sparkatan]

I have the same problem. Tried to open the roof this weekend and the clam shell wouldn't close the last inch or so. Nothing seems untoward with the flaps etc. Tried it several times but no joy.

[ph2426]

I have a very similar issue. The clamshell comes close but then shakes a bit and opens again. It will do this 5 or 6 times and eventually close. 
I have checked the micro switches and they were fine. One thing I do notice is that the top gets pulled down tight when folded but then slightly releases a bit. If I put pressure on the folded top the clamshell closes fine. After a lot of messing it seems this is the issue but not sure why it “sucks” the top down but then after it releases it just maybe half an inch which seems enough to stop the clamshell. Any ideas?

[Sparkatan]

Tried to open the roof again with the same problem and noticed the driver’s side flap stays fully open. I closed it manually by removing the plastic cap on top of the rear seat back and turning the allen screw. Took quite a few turns. The clamshell then fully seated. 
so it would appear to be either an electrical problem or faulty flap motor.

i can see the little motor if i remove the seat back but how can i get to it to test or replace it?