Cab Top Help

[Scotte]

Does anyone have any experience with this? Yesterday I was caught in a torrential downpour and my cab top motor was acting up. So, as per the manual I disconnected the motor using the lug wrench. The motor seems fine now and I was wondering how one goes about reconnecting it. I did the opposite as I did to disconnect but I can just hear the motor whirling and no top movement.

[notfarnow]

I'm no expert, but I've spent hours & hours studying threads here and reading the cabrio top manuals, and two weekends diagnosing and fixing the power top on my father's carrera.

A couple things to look at:

-The "arm" that bolts to the "hub" has to be in position before you can tighten the bolt down fully. If you take the bolt right off and swing the arm off, you'll see what I mean.

-If the raising/lowering motors are spinning but the roof isn't doing anything, one/both of the cables may be broken

-which "motor" do you hear when you use the switch? It could be one of the locking motors. Before the roof will raise, the control module looks for a signal from the locking motor to confirm that it is fully unlatched. A common problem is the brass gear in the locking motor cracks, so the locking motor will keep spinning and the control module doesn't get its signal:

[Scotte]

Jake, I actually lowered it set the arm and tightened it. It raises and lowers now as well as locks. BUT, when the top is closing, it comes crashing down from about 10" or so, into the windshield brackets. And I mean hard.

[notfarnow]

Originally Posted by Scotte

Jake, I actually lowered it set the arm and tightened it. It raises and lowers now as well as locks. BUT, when the top is closing, it comes crashing down from about 10" or so, into the windshield brackets. And I mean hard.

I know exactly what you mean. On dad's top, once the top bow is 90*, it comes down FAST... you need to catch it. I'm sure that's not how it was designed to work. I've pretty much figured out the electrical side, but I have yet to get a hang of the mechanical adjustments.

Did it start doing this just recently?

[Scotte]

Yeah, it just started doing that when I reconnected it.

[notfarnow]

Hmm... dad's didn't start doing it until after we worked on it too.

At one point we fiddled with the lower mount adjustments in order to get the "arm" back on. I've always suspected this caused the roof to come down harder. There seems to be more "slack" as the roof goes upright and starts to close.

Looking at the mechanical movement, it seems that the mount should be adjusted "down" in order to take up the slack that allows it to come down hard.





Again, I haven't quite got my head around the "black art" of cab top adjustment. Hopefully others can weigh in.

[Scotte]

Thanks Jake. I haven't looked at them yet but I will. How about this... it started to rain so I asked my girlfriend to close the top, but make sure you catch it as it falls. She didn't and it came smashing down. Now only the power windshield locks work, but I can still hear the top motor whirring. I'm going to have a look at it after dinner. Any things to look for now?

[Scotte]

Make sure to post this on the forum too so others see it. There are a couple guys who really know these tops.

I assume you mean that the top locking motors are working, but you hear the top motor whirring. Is that right?

Are you trying to open it now? With the header "unlatched", is the the "raising" motor (located behind the rear seats) whirring but not moving the top? If so, wonder if a cable has snapped.


Jake

Yes, and this is what I think I saw before. I'll try to lower manually by loosening the bolts and then setting the arm and retighten the bolts. I'll see what happens.

[notfarnow]

You may want to test the top's "raising/lowering" motor, locking motors & header limit switches.

The control unit is underneath the passenger side floorboard

I wrote up a DIY for testing the electrical components:
http://forums.pelicanparts.com/showthread.php?t=342119

[Scotte]

Well Jake, I think it's officially a manual top now with electrical locking. The swivel gear doesn't seem to be working. Plus, the mounting brackets are cracked from that last impact. How much for a used swivel gear, any ideas?

[911boost]

Be very careful to not snap any of the bows on the top. I would be worried with it crashing down. The top "transmissions" should be providing some resistance to the top closing if you still have them the two support peices bolted to them correctly, and they are functioning the right way. It is fairly easy to check the cables and motors. I recently helped the new owner of my cab and he had a bad motor, which caused only one side of the top to open, thus snapping one of the structural pieces of the top, and putting a substantial hit to his wallet. The motor would run, but when the cable was inserted, it wasn't creating the torque required to turn the cable, and would shut down.

I am not 100% sure that the top in the 964 is the same as the Carrera cars though...

Bill

[notfarnow]

Scotte, are you able to post pictures of the broken parts?


While were on the subject of broken cab frame parts, anyone know a good source? I got an email from my father last night, and it seems we need one of these:

[Scotte]

Ok Jake, I'll try to get some pics. It's not part of the frame it's the part behind the trim panel on the passenger side

[notfarnow]

Originally Posted by Scotte

Ok Jake, I'll try to get some pics. It's not part of the frame it's the part behind the trim panel on the passenger side

Yeah I'd be interested to see where it cracked. You may want to bring it to a specialty welding shop to have it welded up... especially once you see the prices of those transmissions.

There have been some good posts about converting power tops to manual. I'll try to dig some of them up tonight. Essentially, you need to remove the cables & raising/lowering motors. You leave the latching motors and just use the switch to latch/unlatch.

AFJuvat has lots of informative posts on cab tops. If you search using his username, you'll come up with lots of great stuff. Search doesn't seem to be working right now, but I can tell you his posts helped us a whole lot.

One thing that was discussed was how hard it is on the frame when the motors are out of synch. IT'll pull harder on one side and bend/snap pieces. Once we get dad's "dialed in", we're going to convert to manual.

[notfarnow]

Originally Posted by Scotte

Yeah, it just started doing that when I reconnected it.

After re-reading this thread, I called my father and he found the 19mm bolt had come loose on either side. That's why his was coming down hard, probably the same with yours...

In looking at the factory service manual, it says those 19mm bolts need to be replaced with new ones and torqued to 35Nm. Maybe they are stretch bolts?

Here's a thread where AFJuvat talks about using Loctite Blue on the 19mm bolts:

http://forums.pelicanparts.com/showthread.php?t=136131&highlight=cab+top+loctite

I wish there was a good manual for the Cabriolet top that covers all this stuff. The factory electrical manual is pretty good, but the Cabriolet Service manual really doesn't cover much.

[Scotte]

Thanks Jake, I reread that yesterday as well. I'll get some pics... it's not nice outside right now so I don't want to get any more water in there than I have to.

[911boost]

I agree on the lack of a manual.

Can the metal the tops are made out of be welded?

[notfarnow]

Originally Posted by BSiple

Can the metal the tops are made out of be welded?

I've read posts by otheres who have welded up the alloy parts.

FWIW, the local "specialty" welder who fixed my sailboat's mast said he can weld "anything from a broken heart to the crack of dawn"

[meares]

to loosen the locking "cams"...the manual says use a screwdriver tot loosen and tighten.....i can't get a bite on the head of the screw with a phillips or a flat head any help?

[Scotte]

...and here it is: