Difficulty Level: 6 Difficulty scale: Adding air to your tires is level one Rebuilding a BMW Motor is level ten
This article is one in a series that have been released in conjunction with Wayne's new book, 101 Performance Projects for Your BMW 3 Series. The book contains 272 pages of full color projects detailing everything from performance mods to timing the camshafts. With more than 650+ full-color glossy photos accompanying extensive step-by-step procedures, this book is required reading in any 3 Series owner's collection. The book was released in August 2006, and is available for ordering now. See The Official Book Website for more details.
One of the most common complaints of convertible owners is the condition of the rear window. It’s manufactured out of a clear plastic, and as such, it does not have the longevity of a clear glass window. With time and exposure to the elements, the window can become scratched, damaged, or faded.
The good news is the rear window is zipped into place and is relatively easy to replace. I say “relatively” with a note of caution: Although it may seem like a simple process of zipping the window in and out of the convertible top, the actual process is much more difficult and takes quite a bit of patience. The procedure for replacing the window is documented in the sequence of photos accompanying this project.
With your new window in place, you’ll want to keep it pristine and unscratched. To minimize creases and scratches when the top is down, use some terry cloth towels to cover the window whenever the roof is lowered. BMW also has a factory rear window cover you can use to protect the window at all times. For cleaning the rear window, I recommend 3M Plastic Polish or the poly/glass rear window cleaner from Porsche (recommended for the Boxsters).
BMW has its own brand of cleaner (BMW part number 81-22-9-407-666), and BMW factory literature recommends Meguiar’s plastic cleaner #17 (BMW part number 82-14-1-467-128) and Meguiar’s plastic polish #10 (BMW part number 82-14-1-467-129) for heavier cleaning. All of these cleaners will do a good job of keeping your window clean and clear.
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Figure 1
Shown here is a brand-new aftermarket window replacement kit. The kit includes the pre-sewn window, a bottle of contact cement, and a starter zipper. Both aftermarket and OEM replacement windows may not fit as tight as the originals, depending upon the age and condition of your convertible roof.
Figure 2
Begin the process by popping open the roof to relieve tension on the rear window.
Figure 3
Removal of the rear window is straightforward. A: Using a plastic butter knife, or a plastic mechanical pencil, gently separate the roof fabric from the rubber trim. This rubber trim is sewn to the window and will be removed when the window is taken out of the car. B: From the inside of the car, locate and remove the zipper ties from the bottom center of the window. These two were added by an aftermarket installer and don’t necessarily reflect the original factory installation. Carefully pry back the tabs on these clips, and remove them from the window. C: Using your finger, gently separate the window zipper. D: Pull gently on the window, and the zipper should separate, allowing you to remove it from the car.
Figure 4
Insert the new window in place and mate the starter zipper. This is by far the most difficult part of the process. There are no end caps on the zipper teeth, so you may have to use a pair of needle-nose pliers to help get the starter zipper started. Begin by lining up and installing the starter zipper onto the two ends of the zipper teeth that point toward the left, if you’re sitting inside the car facing the rear. The starter zipper should easily make its way clockwise (from the inside of the car) around the edge of the window, using minimal effort (make sure that the fabric and/or window material doesn’t interfere with the starter zipper). The BMW factory manuals say that these teeth should be offset by no more than one in either direction, but in reality you may have to vary them by several teeth in one direction. If the zipper snags or is difficult to move, you may have to realign the zipper teeth on the start one or two teeth in the opposite direction. This was the most time-consuming part of the installation. I ended up varying the zipper teeth about seven teeth to the right in order to install the window with no wrinkles. When you are happy that the window fits properly, use the factory clamps (inset photo) to constrain and lock the zipper (BMW part numbers 54-31-8-134-598 and 54-31-8-134-599).
Figure 5
I found the most frustrating part of the whole process to be the actual zipping in of the window. You have to use a trial-and-error approach to get the window installed properly (it took about 35 tries for me). If the window isn’t lined up perfectly, you will get diagonal creases in the window when the top is up. To eliminate these, you need to release the zipper, then increase or decrease the zipper teeth offset. Moving in one direction or another will allow you to observe if the creases are getting worse or better. If the zipper won’t close without separating, you’re probably way off of the mark—the zipper should very easily make its way around the entire window.
Figure 6
As added protection against the zipper separating, I used two factory clamping plates to sandwich both zippers together. In this regard, I think that the BMW single-clamp design is not sufficiently strong to prevent the zipper from separating. Place one clamp on the outside and one on the inside, and tie them together with thin wire that you can push through the thread surrounding the zipper teeth. With the window properly zipped and installed, peel back the roof fabric and apply a thin bead of contact cement. Wait about five minutes for the cement to harden slightly—and be especially careful not to spill this on your newly installed window. Using a small awl, run it around the inside of the rubber seal, fitting the cloth fabric inside. Press down on the cloth to adhere it to the contact adhesive. The cement is very easy to clean up with a paper towel after it starts to become gooey.
Comments: http://www.emiata.com/E30Window.asp
for the non ZIPPER boys out there
May 24, 2012
lawford1
Comments: Hi I own a BMW Z3 1997 1.9Ltr Last 7 of the VIN LB82028 Hope you can halp me out. I am trying to find the passenger side tension cable for the top as the spring busted but the one's I am finding are totally different from the one that is on the car. Are there two differnt types
April 22, 2012
pilotmike
Comments: i have a 1995 BMW 318is with sewn in factory plastic rear window. is there a replacement kit for it that i can install myself ? my convertable roof is in great shape but my window is shot. will a zipper replacement roof on a 325 work ?
February 19, 2012
joel
Comments: is there a way to convert the saw window to a zippered window? I actually just want to zip it out unless its raining.
November 5, 2011
rambo
Comments: 325i 1988 rear window replacement ... no zipper. Now what. all your instructions work with zippers Can you help?
May 31, 2011
Brian
Comments: I'm looking at the replacement convertible window for a '99 3 series e36. I'm interested to know if your kit includes the zipper pull to install it. In another comment Wayne says he does not konw where to get one. Is that for someon who did not buy the window from you...or do your kits not include them?
May 25, 2011
Comments: I Need instructions on removing and replacing front right Window regulator on a 2000 740i BMW,pictures will help tremendously, Thanks in advance. "Cleat"
Comments: Where can I buy the rubber trim that goes around the canvas opening of the window? Mine is brittle and cracked.
November 29, 2010
Followup from the Pelican Staff: I'm not sure if that is available separately, or whether that's actually part of the whole roof. If memory serves me correct, I think that's part of the roof, unfortunately. - Wayne at Pelican Parts
alex2008x
Comments: hi i have bmw e36 318 and i bought new rear window but doesnt have the zip puller and where can i find it or buy it thank u
September 25, 2010
Followup from the Pelican Staff: I'm not sure, this may be a special BMW tool available from the dealer? - Wayne at Pelican Parts
BimmerLover
Comments: I have a 1987 BMW 325i convertible. I just replaced the roof and all the seals thanks Pelican. In gluing the roof to the bows, I got some contact cement on the interior of the roof. How can I remove this safely without risking the German canvas top or its waterproofability is that a word??
September 13, 2010
Followup from the Pelican Staff: Hmm, I would just try to gently remove it using a brush or a nail file, or something like that. If the color is bothering you, then get some black permanent marker and color out the glue (if it's the yellow super weatherstrip glue). Usually, when this happens to me, I just tend to leave it and disguise it, as you can do more damage sometimes trying to remove it. - Wayne at Pelican Parts
joe325
Comments: Are all rear windows on the 1995 a zipper or are some sewn in?
If they are two varieties what is the easy way to check with out damaging the seals if it is sewn in?
Thank
August 8, 2010
Followup from the Pelican Staff: I think they are all zippered, but you can easily check from inside the car just by looking at the inside of the window where it mates to the top (from the back seat with the top raised). - Wayne at Pelican Parts
Bimmerkid
Comments: Could someone please tell me the part # for the retaining clips used to reclamp the window? I threw mine away.
February 25, 2010
boogie
Comments: you are the first web site that even had my part after 30min. and to boot you had instruction god bless every one of you.its a convertable top plastic window a extremly comon replacement part and nobody had it much less instructio we will msee how it goes
February 23, 2010
fred
Comments: hi, im after a e36 - 325 cinvertable rear window.. $how much are they ?? and will you ship to australia
February 3, 2010
Art
Comments: I have a 1988 BMW 325i convertible. The rear window has come down [the stitching appears to have rotted]. Can it be repaired or replaced? Where can I get a replacement window? Is there anyone in the Viriginia/DC/Maryland area who does these replacements?
December 14, 2009
Followup from the Pelican Staff: I don't know about your local market, but if the actual roof has deteriorated, then you need to probably replace the roof. If not, then follow the instructions in the article here. - Wayne at Pelican Parts
Sean
Comments: I have a 1998 BMW 328 convertible. The outside window trim rubber is pulling away form the canvas top where the window bends. I understand that part of the reason for this is that the width of the rubber trim was a little too short. Do you have replacement rubber trim for the back plastic window?
September 10, 2009
Larry
Comments: I need to re-cement my original window along top edge where it has come loose on its own. Is there a special BMW product I must use or can I use regular old Weldwood Contact Cement?
August 9, 2009
Followup from the Pelican Staff: I don't know of any BMW factory cement for fixing this. - Wayne at Pelican Parts
Bobby
Comments: If the stitching that connects the top to the zipper has broken apart and the window starts to fall down, do you recommend restitching or simply gluing it in place?
July 6, 2009
Followup from the Pelican Staff: Hmm, if the fabric is torn, there may not be too much that you can do to save it. Maybe an iron-on patch from the inside of the car, carefully placed over the edge of the zipper? - Wayne at Pelican Parts
lotek
Comments: the window for my e30conv is not a zipper window instead its the one that u actually have to saw. I wonder if theres a diy for the windows like that.thanks
June 7, 2009
Followup from the Pelican Staff: No DIY as I know it, but the Boxster window is similar and we're probably going to be doing an article on that one in the very near future. - Wayne at Pelican Parts
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