DIY Boxster Convertible Top Canvas R & R

DIY Boxster Convertible Top Canvas R & R
Sincere thanks to Fred Adler for the pictures and instructions, and to others for helping me acquire
them.
I resized the pictures to keep the file size down, and matched them up with the text for easy
reading/printing in PDF form.
Chris in NH, 4/24/2007
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Removal and Replacement of the Boxster convertible top
I never started out to remove and replace the convertible top on my 1998 Boxster but I always believe
in researching and understanding a repair prior to getting quotes on it. My Boxster is my seventh
Porsche always buying them used and it co-resides next to my “retro” Boxster, a 1971 914. The 914
taught me that when Porsches get old they are still loved as much as those rolling out of the local
dealership and that a place like Pelican Parts tech reports can offer a simple alternative to finding
someone who might know about your “older car” or a dealership that might know about your car. I
have used the 914 tech reports and forums to fix, replace and keep driving my “retro” Boxster.
When my Boxster back window finally gave up enough of its plasticizer to crack and split after eight
years in the California sun, the first place I went for guidance was the Boxster tech section. I found
that there was no help on “doing it myself”. I have replaced tops twice before on previously owned
MGB’s which primitive, manual tops available from many OEM sources. Those tops like the ones found
a lot of other small roadsters seem to cost between $200 and $400 dollars and are rather simply put
on by any patient owner. I also tried repairing the back window with one of those “window
replacement” deals selling you “everything you need to sew in a new window”. It did not work well
and after two days with bloody fingers sewing through that incredibly tough German canvas, it leaked
and looked bad………………so on to the total top replacement.
I began researching all of the Boxster websites and chat rooms and all that I could find are discussions
of where to buy tops for between $500 and $900 dollars followed by $1000 to $1800 labor costs to put
them on. I checked ebay for tops and found the different varieties including ones with updated glass
windows ranging from $390 to $1000. When you contact those sellers they recommended a
“professional” installer for installation. Most of those installation quotes including tops are $2000 and
up. When I related this to Pelican Parts chat rooms, they said that perhaps I should try myself and
take a lot of pictures for future Boxster owners. If Boxsters do what 914’s have, most people will be
trying to replace tops themselves 10 or 30 years from now.
And so, here we go. It is not easy to do and takes as much “artistic” sense as basic “handy” skills.
First, choose a top. If you search the web there will be many. I decided to replace the old top with
one most like the original since the updated glass window ones are more expensive and seem to have
“issues” which may compromise the expensive parts and lifting mechanism found in earlier models (up
to 2004). I decided on a top made from “German canvas” (a heavy canvas like the original with a
smooth finish on the outside and a “herringbone” like pattern on the inside) with a “green tinted” back
plastic window. I found one on line for about $400. I took it out of the box for inspection and “feel” to
make sure it was as thick as the old one.
Then I downloaded what was available on “alldata.com” since one top shop told me that is what they
do. I found that information answered some questions but for the most part the diagrams are cryptic
and the instructions extremely short. The Boxster top instructions are between 20 and 30 pages but
still not very clear. Once I started on the top, the instructions really did not show my situation that
closely.
Armed with this and confidence earned by doing several things to my 914 (fuel lines, electronic fuel
systems, starters, etc. thanks to Pelican), I dove into the task of the Boxster top. I figured, how bad
could it be even if I just got the old one off.
Knowing that a Boxster has a lot more parts than a 914, I used the old ziplock bag technique to keep
track of the removal so I would have the best chance of reassembly correctly with no left over parts. I
parked next to a long table to lay the parts out with a box of zip lock bags and a roll of masking tape
to label things as I took them off. You need to make sure it is really nice and warm in your working
area so the canvas top you will be putting on and taking off will be supple and as soft and loose as
possible.
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Here goes the top removal and installation:
1. Put the top in “service mode” which is opening the top from 12 to 18 inches. (Figure 1) Take out
the key so there no chance of further motion. Remove the seat wind stop and seat head rest wind
stops to give you more room to work. Also if you have the console which fits behind the seats,
unlock and remove that also after unclipping the rear drape over the engine.
2. Uncouple the two cables on either side from the rear. (Figure 2) You have to do all of this if you
have ever opened the rear up for SMOG inspection. No smog guy will know how to do this and you
should know this routine anyway.
Now you are in “service mode” and you have removed the easy things.
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With the gap in the front of the top exposed you can see the front edge retaining rail. (Figure 3)
On my 1998, this retaining rail holds in the weather seal and it held to the top frame by six T20 star
screws. Remove these six T20 screws. Remove also the two T20 star screws holding in the left and
right hand corners of the front convertible top seal. Bag the screws and label where they came from.
You can now remove the front retaining rail and set it aside. With the doors open, you can also
carefully pull out the front convertible top seal which goes across the front of the top frame and along
both right and left sides of the top at the top of the window frame area. (Figure 4)
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Next you will approach removal of the sides of the roof frame. The seal at the sides of the roof
frame was held on by a lower “U” shaped bracket. This is where alldata.com was wrong for my
top. They did not have the front and side seals as one part as mine was. The “U” shaped bracket
around 12” in length is held on by 4 T10 star screws. ( Figure 5)
Remove each side labeling them with the masking tape as passenger and driver side and bag the
screws. Once the side weatherstrip holder is removed, you will see four Philips screws. Remove
these screws on each side (passenger and driver) and bag and label them. (Figure 6)
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Now starts the “manual” part” of removal. You will note that the canvas is likely held on with a
double sided adhesive tape. I went to my local Auto Paint shop and purchased a roll of 3M auto
body tape to replace this when reinstalling a new top. You will need at this time to start “peeling
back” the old top from the front edge. With everything that you have removed thus far, you can
peel back the front edge and continue carefully (carefully so as not to damage the top frame, bend
it in any way) along both sides. The same double edged adhesive tape that was used on the front
edge was also used along both sides. Now the top is peeled back to the center support beam of
the roof frame. (Figure 7)
(…and Figure 8)
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This exposes two aluminum guide sheets on either side that fit flush on the roof and to which are
attached the cables which guide the top around the window frames when raising and lowering the
top. (Figure 9)
The cable goes from the center point underneath the aluminum plate around the back of the
window frame and down to a point just below the body on the “B pillar” (the roof support pillar just
behind the window areas). You do not have to worry about the cables since these are provided by
the top manufactures sewed into the new top. I did not cut them but rather was careful with them
since you must now bend the aluminum guides to which they are attached since they need to lay
flush under the new top. The cables on mine were attached to the aluminum plates by way of a
rivet. The cable was attached to a spring and the spring was riveted to the aluminum plate. This
assembly (spring and cable end) were shrink wrapped in plastic. I cut the shrink wrap with a razor
blade and unhooked the cable “eye”. Peel the canvas top off of the aluminum sheets careful not to
bend them, label the aluminum plates passenger and driver side and set aside. (Figure 10)
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Now you will need to detach the other side of the cable you have just been working with. As I said
earlier, this cable terminates on the other end (the end fastened to the “B pillar” (the pillar behind
the windows), below the body line of the car. To get at this screw, lower the top about 75%. This
screw and cable will become visible. (Figure 11)
This was again a T20 star screw. You will note that the screw goes through a flap on the top, the
lower cable eye, a plastic part which runs up from the screw called the “clamping rail and slider”
and into the B pillar. Carefully remove the screw and DON”T DROP IT” since it will be really
difficult to retrieve. When removed from passenger and driver side, bag them and label them.
They have a lock washer. Remember the clamping rail and slider for later.
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Now you are back to the middle support frame. The top has a flap and piping which was slid into a
plastic cover on this middle frame. (Figure 12) Note that there is a metal clip which holds this
plastic cover onto the middle frame. Pry it off, noting how it was snapped in place. Now the
plastic frame will lift off and you can slide the canvas flap out of it. Set aside the plastic cover for
the middle frame.
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At this point, I felt like I wanted to work elsewhere so I went to rear of the top and started
removing it. Put the top back up to about 12-18 inches open. First there is a push in weather strip
which seals the trunk from the top. This pulls out easily. Be careful since the replacement Porsche
part is no doubt expensive and this sort of weather strip like the front seal can be torn. Put is
aside labeling top and bottom with masking tape. Carefully peel up the top from the weather strip
channel. Yes, more of that infernal double-sided adhesive tape. (Figure 13 and 14)
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This exposes another flat weather strip to the rear of another push in piece of plastic striping. Pull
out the flat push down weather strip on the rearmost part of the frame. Because you have the top
in “service mode”, the rear part of the top hinges loose and these strips are easier to remove.
Carefully pull out this weather strip as well, label it and put it aside. Now for the top attachment to
the rearmost part of the frame. Yes the adhesive was partly responsible, but the top also has a
flap which was inserted in another grove parallel to the last weather strip that you removed held in
place by a long wedge shaped piece of plastic that fits into that groove after the top flap in the rear
was inserted into it. Pull this out and the canvas is now loose from the rearmost frame bar. (Figure
15)
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Now back to those “clamping rails and sliders” that you were working on just behind the “B Pillar”.
You loosened them from the car when you unscrewed the back end of the top cables. They are
also held on by a couple very fragile pins. The “clamping rail and slider assembly” is a two part
assembly held together and to the car by two black plastic pins. These act like “hinge” pins on the
assembly with the lower one holding the two plastic parts together and the upper one acting as a
guide along which the clamping rail and slider can slide back and forth a few centimeters. Pull
these two pins on each side with a long nose pliers being careful not to damage the clamping rail
and slider assembly or you will be going to the Porsche dealer ordering those parts. Now you will
note that with these two parts disassembled on each passenger and driver side that again there
are top canvas flaps tucked into each component. Slide the top flaps out of them and remove
them labeling them passenger and driver and noting how they went together. I reassembled them
so I could not forget how they go together although it is rather obvious.
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10 You are almost THERE!! On the top support going across from the B Pillar you will note two canvas
straps screwed into the cross support by two each T20 star screws. Unfasten those and put aside.
(Figure 16)
You will also notice two (one on each side) Velcro’ed loops holding the top on the sides of the
frame (“push bars”). Open those up. (Figure 17)
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11 You will now note that it seems like there is only one thing left holding on the top. You are right.
The canvas top has another flap behind the flap that was slid into the #2 bar going across by way
of that plastic cover. This flap, however, on bar #3 (#1 is the front one), is slid right into the bar.
When you slide it out, the top comes OFF. You will figure out that this is the very first thing you do
in reverse on assembly. There is no way to get this flap in place when anything else is fastening
the top to the frame.
12 OK the top is OFF, about 2-3 hours later than you started and you have the whole process fresh in
your mind. For installation, you have to make sure you have that double sided adhesive tape (3M
Automotive, Figure 18),
…and some denatured alcohol (Home Depot) to clean the areas to which you plan to apply the new
tape. Clean and pull off all the old double sided tape from the front edge of the frame, the sides on
the aluminum parts, the back edge and anywhere else that the installer may have put it. I suspect
that some people put more on since fitting the new top is no picnic. It takes a lot checking and
rechecking for evenness and position.
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13 Take the OLD top now and compare it to the new on to make sure it is almost the same if not
perfectly the same. I am sure that Porsche made changes along the way. Also assure that the
new one has the new cables sewn into the channels on both sides of the new canvas.
14 NOW, reverse the process for installation. Remember the very first thing to do is to slide the #3
channel flap into that flap. Next, I reassembled the clamping rail and slider assemblies on either
side. Remember to match the flaps on the new top to the appropriate slots on the clamping rail
and sliders and slide them in. With the flaps slid in place, you can assemble the two parts of the
clamping rail and slider and gently position them back into their original locations. You will have to
tuck parts of the top between the body of the car and the B Pillar like the way they originally were
fit. Put the top attached to the clamping rail and slider back into position (assembled) and line up
the bottom of them with the cable screw hole and the black plastic pin positions and reinsert the
pins to hold them together in place.
15 Lower the top 75% making sure that the clamping rail and slider assemblies don’t move and attach
the lower end of the top cable through a tab in the top at that location (you may need to punch a
hole in the tab as I did), the lock washer, the cable eye into the hole and tighten them.
16 I now went around back again. Raise the top to the “service position” again (12-18 inches open).
Start with inserting the rear tab into the channel and holding it in place with the “wedge shaped”
plastic strip. I found that using a silicon spray on the strips helped enormously getting them into
place and flush. I would spray the whole strip before inserting. Now the top canvas rear is
attached to the rear cross bar. Push back in, with silicon spray the “flat weather strip” from the
rear of the top. Next, the double sided tape in reverse. Apply to a cleaned surface (denatured
alcohol worked well), the double sided tape in the channel for the trunk weather stripping.
SMOOTH the trailing edge of the canvas top into that channel keeping in mind that it must be
SMOOTH if you are to fit the final weather stripping into that channel. If you got the right adhesive
and cleaned before applying, it will stay in place when smoothed onto the adhesive. Siliconize the
rear trunk weather stripping and push it into place.
17 Re-attach the two canvas strips running back to front with the two T20 star screws as they were
when you removed them.
18 Now for the side aluminum panels. Attach the forward edge of the cable to the spring on each
aluminum panel like when you removed them and wrap the old shrink that you slit with electrical
tape. The assembly should now lie nicely on the top (flat to the top). If it does not you either
have the passenger at the driver side or you put it backwards. It will lay flat with the front edge
even with the front top frame cross bar.
19 Here is where it gets artsy. Pull the canvas top as even and tight to the front as you can. Smooth
the top as much as you can. If it is not even, you won’t be adhering it evenly and it will result in
wrinkles on the final top assembly.
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20 Apply more of the double sided adhesive where it was on the two aluminum panels. You can
approximate location on the canvas by laying it over the aluminum and marking the back side of
the canvas with a marker. (Figure 19)
The canvas will wrap around the aluminum as it was when you took it off. It will fit in the channel
along side of the aluminum. You can determine if the aluminum is placed correctly since the prior
holes in the aluminum sheets should line up with the holes in the frame from the under side. This
step takes patience and some fooling with it to get it right. Do both sides and the top should be
smooth across. Refasten the aluminum panels with the canvas covering with the Philips screws
from the under side. Try to get it right or you will be backing out of the procedure and doing it
again if you don’t like the wrinkles.
21 Front edge attachment next. More cleaning and more adhesive along the front edge. The front
edge will have a leather or cardboard strip to help you line it up parallel and tight. The adhesive
will hold it in place but I also used a couple plastic spring wood clamps to pinch it in place so I can
walk around and make sure it was even and straight. You will see how the corners tuck in but
remember that these are covered by a weather strip anyway.
22 I now backed off the top to a comfortable openness so I could get retaining rail and weather strip
back on. With the front edge adhered, screw in the corners of the front weather strip with the two
T20 screws. Screw in the side weather strip holders. Siliconize the side weather strip extensions
of the front weather strip and push them into the holders on either side.
23 Now you only have the front retaining rail left. With the weather strip in front in place, hold up the
retaining rail and line up the holes. I used those clamps here to hold the assembly while I refastened the front retaining rail.
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24 Everyone says the new top will be tight. To help at this point, I moved the car out into the
California sun to heat it up. After about a half hour, I went around back and reattached the two
cables on either side of the engine compartment. I then backed off the top about half way and
then closed it until the light on the dash went off. That was close enough to catch the closing hook
in the center of the inside of the car and swing the latch shut. I left the car in the sun for the rest
of the afternoon and then open and closed it a few times to assure my satisfaction. (Figure 20) I
reassembled the console and the wind stops and voila, I was exhausted.
I hope this helps. There is some art in this. When I was young, I worked in a tailor shop so I am
good at spotting one leg being longer than the other. That helped with this but doing it myself
saved about $1500. I can live with a little wrinkle. If not, you have to loosen up things from the
first steps again up to where you see the wrinkles, likely on the sides, and smooth it out. Good
luck.
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