[sksail]

I have read a few of the threads and I guess there are a few of you who have had this problem and I was looking for some advice.
Last fall I was raising the top with motor and heard a loud snap. I converted to manual mode and the top still worked but sagged on the passenger side.
I took it to my mechanic, he tried to fix it but said he thought I might need a new top. He was going to check into getting a part to fix it, but I have not heard back from him. It is winter up here in maine and I haven't bothered to pester my mechanic as I won't drive the car for another month or two.

Since it is snowing yet again, and I am on call this weekend. I thought I would try to figure this out.
It turns out the repair that my mechanic tried was to try to splint the crack in the main bow by drilling a few screws through the rail that holds the gaskets for the window. He tried to fix both sides of the crack in the bow to the rail. Clever, but the stress was too much for the rail and the screws pulled out.

I have managed to expose the bow and I am planning on taking it out. I was wondering if I should order a new bow and try to fix this on my own, try to fix this broken one (though I am not sure a weld would work) or take my mechanics advice and get a new top. I did read one thread were flash was talking about a repair kit for this problem.

I would welcome any suggestions

Thanks
Steve

here is a photo of the broken bow
   

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[banditsc]

A new top wouldn't do anything for that issue, you just need to replace the bow. You can get a used one for much cheaper then new, that's the route I went. When I put the replacement in, I filled the void areas between the ribs on the backside with JB Weld, it's probably not going to do anything, but I made me feel better.

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[DiREW0LF]

Is there an approximate mileage that this seems to occur? Obviously how often the top is put up and down and other factors would have an effect on how long before a failure.

Is there anything that can be done to prevent this from happening?

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[Anchorman]

I believe I'm the oldest "voice" on this issue, having suffered a broken main bow on the driver's side nearly six years ago (and only a month or so after having purchased my cab).

The cause seems to be the top motors getting (maybe even ever so slightly) out of synch and creating a twisting force on the top mechanism. There doesn't seem to be any mileage or age correlation - probably paying close attention to how easily (or not) the top operates, and addressing any issues promptly, before the breakage, is the only "medication". The only known permanent cure is to operate the top in manual - which is what I've done, with no complaints, for the last six years.

If you haven't downloaded the top manual, you should do so - particularly if you plan to go back to power operation. The manual gives instructions on how to synchronize the top motors.

When my bow broke, I had the repair done at my Porsche dealer - not cheap! A new top has nothing to do with this issue.

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[flash]

for crying out loud - why can't this happen on THIS side of the country? we have been waiting for 4 years for this to happen to a car out here so that we can get the repair kit made - STILL waiting on one - that being said, i sure hope it isn't mine

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[sksail]

Thanks everyone.

I did download the top manual, doesn't say much about replacing the bow, but should come in handy when I eventually have to align the top again.
I don't think I will go back to using the power top. It is just as easy to do it manually.

I wish I could drop it off for you flash, but might be cheaper to fly you out here. not that you would want to be here now, we just got another foot of snow today.

Any suggestions on where to get a main bow? Tried DC automotive and they don't have any in stock. I was going to try to call sunset.

I guess I'll work on getting the main bow out and see if I can fix it on my own. I'll keep you posted.

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[flash]

lol - wouldn't be me doing it - i have an upholstery shop here that did the repair before and wanted to make a kit for it - unfortunately he did not make a template, and needs another car so that he can do that

still waiting

josephsc probably still has a complete black top and bow set - not sure if he'll separate them or not

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[jbaarman]

I had this happen about a year ago. It seems fairly common that these main bows break. (The main bow is not the part in your picture that holds the rubber, it is the part underneath the canvas that breaks causing the outer part to break). They are expensive to replace new, and tough to find from a salvage yard. From talking to the salvage guys, it seems like they have more requests for the driver's side, so a passenger side main bow may be easier to find.

I took mine to an old timer welder who braced and reinforced it when he welded it. I needed my top replaced so I hired a mobile upholstery/convertible top guy who came to my garage and removed the old top while he was waiting for the new one he ordered to come in. Then I removed the main bows and took them to the welder. I had him do the same thing to the passenger side which wasn't broken. He did both for $100. My logic was, why pay for a new part that has an inherent weakness.

I will try to post a picture of the main bow that shows how he reinforced it when I get back to my home computer. I will also find the name to the vendor I got the top from. It was a great price and is nice German canvas. The hole thing, installed, was less than $1500.

I also switched to manual mode. I figured I got out of the car anyway to smooth the crease and put a towel in, so why not.

Jim

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[jbaarman]

Oops. After looking at the picture again... I was wrong. That is the main bow with the canvas removed.

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[josephsc]

<!--quoteo(post=67886:date=Mar 1 2009, 08:41 PM:name=flash)-->QUOTE (flash @ Mar 1 2009, 08:41 PM) <{POST_SNAPBACK}><!--quotec-->for crying out loud - why can't this happen on THIS side of the country? we have been waiting for 4 years for this to happen to a car out here so that we can get the repair kit made - STILL waiting on one - that being said, i sure hope it isn't mine<!--QuoteEnd--><!--QuoteEEnd-->
4 years? Really? We've have got to talk more often! It happened to the purple cab two years ago -- and I still haven't gotten around to repairing it.

<!--quoteo(post=67914:date=Mar 2 2009, 04:57 PM:name=flash)-->QUOTE (flash @ Mar 2 2009, 04:57 PM) <{POST_SNAPBACK}><!--quotec-->josephsc probably still has a complete black top and bow set - not sure if he'll separate them or not<!--QuoteEnd--><!--QuoteEEnd-->
Need it for the purple cab....

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[flash]

lol - ah - well then

here's an idea though - when you get the top off the purple car, send me, bring me, whatever, the broken frame - then i can have the kit made

hopefully it would fit in the trunk of the cab - then you could drag it to paso

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[josephsc]

Not a bad idea -- I'll get moving on getting it to you.

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[flash]

yeah - seemed decent to me - then at least the guy can have the kits ready for everybody - apparently welding doesn't last long (crappy metal), and so the repair kit makes a lot of sense

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[rxter]

<!--quoteo(post=67886:date=Mar 1 2009, 08:41 PM:name=flash)-->QUOTE (flash @ Mar 1 2009, 08:41 PM) <{POST_SNAPBACK}><!--quotec-->for crying out loud - why can't this happen on THIS side of the country? we have been waiting for 4 years for this to happen to a car out here so that we can get the repair kit made - STILL waiting on one - that being said, i sure hope it isn't mine<!--QuoteEnd--><!--QuoteEEnd-->

Can't help you - went to manual mode. The motor was 'cool', but too slow, too aggravating, and too much stress on the bow and me.

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[jbaarman]

<!--quoteo(post=67883:date=Mar 1 2009, 09:49 PM:name=DiREW0LF)-->QUOTE (DiREW0LF @ Mar 1 2009, 09:49 PM) <{POST_SNAPBACK}><!--quotec-->Is there an approximate mileage that this seems to occur? Obviously how often the top is put up and down and other factors would have an effect on how long before a failure.

Is there anything that can be done to prevent this from happening?<!--QuoteEnd--><!--QuoteEEnd-->

A theory as to why the Main Bow breaks:
When mine broke I took it out (the top was off), brought it to a welder for repair, and when I tried to reinstall it, I had trouble getting all the bolts to line up that attach the other frame bars. I found a tension adjuster under the speaker cover. When I loosened it I got all the bolts back in and then when I re-tightened the adjuster I could actually see the torque or flex being brought to bear on the Main Bow. I adjusted it until I just started feeling resistance. So, my theory was that the car was riding around with too much tension on that Main Bow and that, combined with the weakness of the part, over time caused it to break. Just of theory but if it is true it is worth it to check those adjusters (sorry I didn’t take pictures) on both sides as a preventative measure. To remove the top and repair or replace that part is some bucks.

I also converted to manual operation but I can’t figure how the motor would cause the Main Bow to break.

Jim

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[biotechee]

So all one needs to do to convert to manual operation of the top is to loosen the bolts that are accessed via the side panels (behind the windscreen mounting rosettes)? This is what I read in the convertible top service info manual posted in the library.... Can someone confirm? I would like to switch to manual operation but I don't want to screw anything up in the process.

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[Darryl]

<!--quoteo(post=70740:date=Apr 23 2009, 10:01 AM:name=biotechee)-->QUOTE (biotechee @ Apr 23 2009, 10:01 AM) <{POST_SNAPBACK}><!--quotec-->So all one needs to do to convert to manual operation of the top is to loosen the bolts that are accessed via the side panels (behind the windscreen mounting rosettes)? This is what I read in the convertible top service info manual posted in the library.... Can someone confirm? I would like to switch to manual operation but I don't want to screw anything up in the process.<!--QuoteEnd--><!--QuoteEEnd-->

You'll screw nothing up going to manual mode. It's much better (IMO) and much less risk. I completely agree with rxter...power top is cool, but too slow and you normally get out of the car anyway. 19mm socket or use the factory lug wrench in the tool kit.

- Darryl

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[madridcab]

On my 964 from memory there was an issue with "warning light" in the dash being on when operating in manual mode, any such issue on a 968? If at a later stage you want to switch back to power mode, do you just re-tighten the bolts in the same position (say you loosen them in the top up position, you re-tighten in the same position)? Do you need to pull a fuse or disconnect the switch in the dash to avoid accidentally start operating the motors while in the "manual mode"?

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[jbaarman]

<!--quoteo(post=70762:date=Apr 23 2009, 05:01 PM:name=madridcab)-->QUOTE (madridcab @ Apr 23 2009, 05:01 PM) <{POST_SNAPBACK}><!--quotec-->On my 964 from memory there was an issue with "warning light" in the dash being on when operating in manual mode, any such issue on a 968? If at a later stage you want to switch back to power mode, do you just re-tighten the bolts in the same position (say you loosen them in the top up position, you re-tighten in the same position)? Do you need to pull a fuse or disconnect the switch in the dash to avoid accidentally start operating the motors while in the "manual mode"?<!--QuoteEnd--><!--QuoteEEnd-->
All that happens when you loosen that bolt is you disengage the gears. You don't even need to take the bolt out, just a couple turns will do it. I does not disconnect the electric and you will not get any warning light. It was designed as a mechansim to be able to move the top if your motor failed. Re-tighten the bolts and the gears will be re-engaged. Make sure you do both sides. There are two motors and gears on both sides. You could unplug the console switches and still not get any lights.
I find it faster and more convenient but I do not believe it prevents main bow breakage. With the canvas removed, I ran the top up and down and did not see anywhere in the folding process where any level of stress was put on the main bow. However, I think if you had the tool and strength and could keep cranking that tension adjuster, you would cause the main bow to snap and they would all probably break in the same spot, where the hole in the main bow makes it structurally weak.
If you get out of the car anyway to smooth the window, go for it. It does no harm.

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[flash]

bow breakage is related to the motors being out of synch and/or a cable bind - it takes very little for this to happen - running in manual mode will avoid breakage - i was actually looking forward to finally having a power top when i got this car, having had almost all manual ones, and then when i got it and found out how complicated it was, i went manual

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