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Convertible top replacement
Submitted By: fixb52s
Date Created: 04-25-2006
Description: The top on this car is shot. The rear window was gone, and the canvas is torn and cut. It might have been reusable if items were not thrown at/on it when it sat in the carport. When this car was purchaced it seemed like an easy thing to replace, but in reality it is not for the weak of heart or inexperenced. Some knowledge of fabric work is helpful, along with the ability to take your time. This job is not to be rushed. Items required are the new top, glue (contact cement) either spray or brush, RTV black sealant, tape, adhesive solvent and new parts as required (hardware, seals, etc.).
Related Projects: 1989 BMW 325ic Restoration
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Seen better days
The top is beyond repair. It was replaced in the past so it is not factory. The German canvas material itself seems in good shape...except where it was torn.

This might have been saved with a new rear window if it was not torn to hell. Local shops quoted $1300 to 1500 to replace it. Ouch.
Patches will not work


New top
This is the top that was ordered from Nachos Auto Upholstery in North Hollywood, CA. It is made with original German canvas material and cost $380 shipped. There are tops on the market made with Stayfast canvas for about a $40-60 savings, but they do not have the herringbone pattern on the back (inside) of the material. Some Stayfast tops just looked cheap. There is also another newer material available that is in use by BMW, but that costs more and is not really required. This roof is top quality.

I called the shops again to see how much it would be for them to install this top. $500-600 for the labor only. Any other materials that might be needed would be extra. Instructions were downloaded from the net. It looks involved, but it doesn't seem too difficult as long as care is taken.
Inside new top


Remove panel
The first thing to do is remove the top boot so it doesn't get in the way.

The front and side seals were removed. The front seal is in bad shape and will be replaced (Another $150). The others are fine and can be reused.
Seperating seals


Seperating the canvas
Removing the canvas is as easy as cutting it off.... along with seperating the glued ends from the frame. Take notes and photos to see how it was installed. This will be a big help later if you have any concerns when installing the new one.

The old top is removed from the frame. This picture looks worse than it really is.
Gone with the old


Framed
1/2 done, right? No no. The frame has to be checked over for anything that could cause problems down the road. Things like srtraight bows, joints, etc. must all be fixed now before the new top can go on.

All the old glue that held the old material on must be removed. Adhesive remover makes this job a lottle easier, but it is still work.
Old sticky


Rear frame
The rear of the frame shown with 1/2 the glue removed. This is a process that takes some time, but all traces of the glue must be removed to ensure a proper job. It is a good thing this is car never spent time up north as the frame is rust free.

The frame is now cleaned and all pivot points have been oiled. One important item that must be good is the straps that run along both sides of the frame. They are elastic from the factory and should be replaced even it the elastic seems good. The elastic helps in folding the top, but goes bad in time, allowing the top to sag. This top was replaced before, and the straps have been replaced. They are made from a belt material having no elastic. They are still in good shape and can be reused, but care must be taken when folding the top.
Frame complete


Test fit top
The new top is placed on the frame to check for fit. A dry fit is important prior to the glueing and trimming process. If it does not fit now it can be returned. Tops cannot be returned if they had been trimmed because how many tops can these companies replace due to installation errors on the installer? This is why they always suggest professional installation.

The main concern when installing a top is the proper setting and trimming. It is extremely important to ensure the top is set in the right spot before gluing it to the frame. If the glue sets and the rear window is not centered, well you are SOL. The flaps come large to allow for a custom fit since there can be minor differences between different cars.
Proper setting


Proper trimming
Be careful when trimming. Taking too much off is not a good thing. Take your time. Here is the back rail trimmed with the weather seal channel installed.

After the rear is glued in place, the front of the top is glued to the header. Again, proper fitting is a must. The front header needs to be flipped up to install the fabric. It must be placed properly because because when the top is up (frame fully extended), the fabric becomes taunt. The fit will be proper if the bow flaps are centered with the front bow when the header is up. After the glue sets and you lower the header, you will see the fabric stretch, but the bow flaps will still be centered with the bows. If you see this, pat yourself on the back.
Bow check


Header
The front weatherseal channel is installed after applying a bead of sealant on it. This sealant is critical to prevent leaks.

The new front seal is pressed into position. Sealant is applied at the corners where they transition to the side window.
Front seal


Let dry
The header is latched down overnight to allow the sealant to set. Any excess is cleaned off at this time. A dab of sealant is also applied in the rear corners where they meet the 1/4 window seal. The window is raised and allowed to cure overnight. This keeps the window seal opened enough so the window will travel properly into the seal when raised.

The bow flaps are glued and wrapped around the bows. First, the rear wrap is glued to the bow, then the second is wrapped around the first.
Bows


Completed bows
the bows now look clean and the wraps will prevent the roof from ballooning when at speed.

The top is complete, but a few minor frame adjustments must be made so the right rear boot will meet the car better. Total cost to replace it (including top and supplies) was just a tad over $530, including the new front seal. A lot better than the $1500 local price(not including the seal). This was not a difficult job, but it required a LOT of time to ensure it was replaced correctly.
Completed top

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