Hi everyone,
Some of you will know my read window glue failed due to age. Fingers crossed it is now fixed so I knocked up a guide to help others. There is a PDF you can download or look below.
Link to PDF is here - coming soon !
Audi A4 Cabriolet 2003 roof rear windows glass repair guide (applies to many other vehicles too)
· Common fault on older Audi cabriolets and other soft tops is the fabric coming away / unbounded from the glass rear window.
· There is no official fix for this from Audi other than a new roof skin.
· Options are new roof skin from Audi - £2000 approx I believe but do check.
§ OR breakers yard roof – risky as it will probably have a the same issue.
§ Buy a OEM 3rd party new skin - £600 approx excluding fitting
§ Fix it yourself.
· What WONT work is
o Silicone sealant
o Gorilla Glue – it expands on application and is impossible to control.
o 3M double sided tape – I tried it and it failed in under a day.
· What will (probably) work – a single part polyurethane black adhesive used for fitting car windscreens. However the preparation is key to this working.
(My roof had failed on both sides)
Things you will need
Tape – I used the blue car sort tack detailing tape (all the tape in my pictures is this). I used it so it wouldn’t leave a sticky residue on the roof fabric.
Clamps – I bought some deep G-clamps (the blue ones in the pics) – they need to be deep to reach the edge of the glass. They were about £9 each on EBay and other places. I also used a couple of slide sash type clamps too.
Plastic sheet – Once the roof is partially open I covered the rear deck section with plastic sheeting to protect it from spills etc. The chemicals used in this process are very sticky and aren’t easily removed from trim and paintwork etc.
Gloves – see above lol.
Pillows – Used to support the glass and take the strain away from the joint as it cures.
Wood – you will need a chunky piece of wood to support the rear of the roof once open. SAFETY – THE ROOF ONLY STAYS IN POSITION A FEW MINUTES ONCE OPEN AFTER WHICH IT WILL RELAX INTO A NEAR CLOSED POSITION – DONT GET YOUR FINGERS OR ARM STUCK. The wood block stops it closing. Have a wider flat piece as well to spread the load. Avoid the seal as well on the underside of the roof.
I opened the roof so the glass was about horizontal and then used pillows to take the weight off the glass. This is also important as it allows the wooden former to be inserted over the fabric and to clamp onto the fabric/glass joint. If the glass is pulling down under its own weight you wont get the wooden former in. This is also why its important to tape the fabric so the adhesive wont glue the former to the fabric.
Plywood former - made a wooden former to aid clamping the joint. I got a large piece of paper and traced the window and then cut it from thin ply with a jigsaw. I make 2 one for each side for ease. The upper edge of the former corresponds with the line of the fabric as it overlap the glass. Once clamped onto the former this pushes the fabric directly onto the glass bonding area.
Sealant – I used a Dinitrol 500 kit that came with a bottle of 520 (activator and cleaner) and 530 (glass paint primer). It was £15 on eBay.
The repair process
Pick a warm and dry day. You will need a good 4 to 6 hours for this if you use this method. You can leave it for longer if you wish, the longer the better.
Prepare the surfaces.
This bit is very important – you need to make sure when you bond the glass back you maintain the original straight lines where the fabric was originally bonded or it will look like an obvious repair. I used blue tape on the glass window to mark where the fabric needed to line up to. This also gives a masking line for the black paint Dinitol 530 primer (more on this later).
I also used blue tape on the fabric to protect it from the adhesive, I very slightly ran it over the edge towards the glass too.
Where the glass has come away there will be what looks like a brown or black fabric strip on the glass. I removed all this with a sharp bladed scraper (try to get a razor blade one rather than a cheap paint scraper). The aim here to remove anything that is loose or that you think will give way at a later stage.
On the fabric side I just made sure there was nothing loose or any remains of an old repair like silicone or glue.
Once clean use the Dinitol 520 to wipe down the glass where the bond will be and I also wiped the underside of the roof fabric too. Wipe this all off with a CLEAN cloth after 2 or 3 mins.
Then you can paint on the Dinitol 530 primer paint. Don’t use too much it needs a thin coat which dries in about 10 to 15 minutes. It MUST be completely dry before applying the adhesive. I applied it to the glass and the fabric.
Before applying the adhesive DO NOT touch the surfaces after applying the primer paint.
Have some strips of blue tape ready – you will need this to tape ACROSS the joints to pull the fabric in line with the tape on the glass showing where the fabric should sit in straight lines (ie how it was originally bonded). Don’t worry about the adhesive sticking to it, it will come off.
Applying the adhesive
Put on 2 or 3 pairs of disposable gloves. As soon as you get adhesive on a glove remove it, you do not want adhesive on the fabric or your skin.
I didn’t use the nozzle supplied, I used a normal sized one and ran 2 small (4 to 5) mm beads along the glass. Don’t put too much down or it gets very messy. Make very sure you get adhesive onto the glass in the very bottom corners all over as this is the weak spot.
Be careful not to apply too much as if it leaks out under the fabric it will stain the headlining.
Fixing and clamping
Once adhesive is applied and tape is in place to hold the fabric seams straight, I used the 4 clamps to hold the fabric / glass under compression for about 4 hours.
Be careful as the glass it curved so if your wooden blocks or former are too stiff you could break the glass. The aim here is to pinch the joint tight as it cures and not clamp it very tight. It is to stop movement of the fabric so it sets in the correct alignment.
]
The Dinitol 500 skins over in an hour to so (depends on temperature). Once skinned and I was happy I removed the tape so to remove as much excess adhesive as I could. Again a razor scraper can be used to remove excess adhesive and also the primer. As long as the tape on the fabric has stayed in place you should have no adhesive visible on the fabric itself.
Leave it clamped for at least 4 hours, longer if possible.
I wrote this guide the day after I did my own roof, time will tell if it has worked. It should look like this.
Some of you will know my read window glue failed due to age. Fingers crossed it is now fixed so I knocked up a guide to help others. There is a PDF you can download or look below.
Link to PDF is here - coming soon !
Audi A4 Cabriolet 2003 roof rear windows glass repair guide (applies to many other vehicles too)
· Common fault on older Audi cabriolets and other soft tops is the fabric coming away / unbounded from the glass rear window.
· There is no official fix for this from Audi other than a new roof skin.
· Options are new roof skin from Audi - £2000 approx I believe but do check.
§ OR breakers yard roof – risky as it will probably have a the same issue.
§ Buy a OEM 3rd party new skin - £600 approx excluding fitting
§ Fix it yourself.
· What WONT work is
o Silicone sealant
o Gorilla Glue – it expands on application and is impossible to control.
o 3M double sided tape – I tried it and it failed in under a day.
· What will (probably) work – a single part polyurethane black adhesive used for fitting car windscreens. However the preparation is key to this working.
(My roof had failed on both sides)
Things you will need
Tape – I used the blue car sort tack detailing tape (all the tape in my pictures is this). I used it so it wouldn’t leave a sticky residue on the roof fabric.
Clamps – I bought some deep G-clamps (the blue ones in the pics) – they need to be deep to reach the edge of the glass. They were about £9 each on EBay and other places. I also used a couple of slide sash type clamps too.
Plastic sheet – Once the roof is partially open I covered the rear deck section with plastic sheeting to protect it from spills etc. The chemicals used in this process are very sticky and aren’t easily removed from trim and paintwork etc.
Gloves – see above lol.
Pillows – Used to support the glass and take the strain away from the joint as it cures.
Wood – you will need a chunky piece of wood to support the rear of the roof once open. SAFETY – THE ROOF ONLY STAYS IN POSITION A FEW MINUTES ONCE OPEN AFTER WHICH IT WILL RELAX INTO A NEAR CLOSED POSITION – DONT GET YOUR FINGERS OR ARM STUCK. The wood block stops it closing. Have a wider flat piece as well to spread the load. Avoid the seal as well on the underside of the roof.
I opened the roof so the glass was about horizontal and then used pillows to take the weight off the glass. This is also important as it allows the wooden former to be inserted over the fabric and to clamp onto the fabric/glass joint. If the glass is pulling down under its own weight you wont get the wooden former in. This is also why its important to tape the fabric so the adhesive wont glue the former to the fabric.
Plywood former - made a wooden former to aid clamping the joint. I got a large piece of paper and traced the window and then cut it from thin ply with a jigsaw. I make 2 one for each side for ease. The upper edge of the former corresponds with the line of the fabric as it overlap the glass. Once clamped onto the former this pushes the fabric directly onto the glass bonding area.
Sealant – I used a Dinitrol 500 kit that came with a bottle of 520 (activator and cleaner) and 530 (glass paint primer). It was £15 on eBay.
The repair process
Pick a warm and dry day. You will need a good 4 to 6 hours for this if you use this method. You can leave it for longer if you wish, the longer the better.
Prepare the surfaces.
This bit is very important – you need to make sure when you bond the glass back you maintain the original straight lines where the fabric was originally bonded or it will look like an obvious repair. I used blue tape on the glass window to mark where the fabric needed to line up to. This also gives a masking line for the black paint Dinitol 530 primer (more on this later).
I also used blue tape on the fabric to protect it from the adhesive, I very slightly ran it over the edge towards the glass too.
Where the glass has come away there will be what looks like a brown or black fabric strip on the glass. I removed all this with a sharp bladed scraper (try to get a razor blade one rather than a cheap paint scraper). The aim here to remove anything that is loose or that you think will give way at a later stage.
On the fabric side I just made sure there was nothing loose or any remains of an old repair like silicone or glue.
Once clean use the Dinitol 520 to wipe down the glass where the bond will be and I also wiped the underside of the roof fabric too. Wipe this all off with a CLEAN cloth after 2 or 3 mins.
Then you can paint on the Dinitol 530 primer paint. Don’t use too much it needs a thin coat which dries in about 10 to 15 minutes. It MUST be completely dry before applying the adhesive. I applied it to the glass and the fabric.
Before applying the adhesive DO NOT touch the surfaces after applying the primer paint.
Have some strips of blue tape ready – you will need this to tape ACROSS the joints to pull the fabric in line with the tape on the glass showing where the fabric should sit in straight lines (ie how it was originally bonded). Don’t worry about the adhesive sticking to it, it will come off.
Applying the adhesive
Put on 2 or 3 pairs of disposable gloves. As soon as you get adhesive on a glove remove it, you do not want adhesive on the fabric or your skin.
I didn’t use the nozzle supplied, I used a normal sized one and ran 2 small (4 to 5) mm beads along the glass. Don’t put too much down or it gets very messy. Make very sure you get adhesive onto the glass in the very bottom corners all over as this is the weak spot.
Be careful not to apply too much as if it leaks out under the fabric it will stain the headlining.
Fixing and clamping
Once adhesive is applied and tape is in place to hold the fabric seams straight, I used the 4 clamps to hold the fabric / glass under compression for about 4 hours.
Be careful as the glass it curved so if your wooden blocks or former are too stiff you could break the glass. The aim here is to pinch the joint tight as it cures and not clamp it very tight. It is to stop movement of the fabric so it sets in the correct alignment.
]
The Dinitol 500 skins over in an hour to so (depends on temperature). Once skinned and I was happy I removed the tape so to remove as much excess adhesive as I could. Again a razor scraper can be used to remove excess adhesive and also the primer. As long as the tape on the fabric has stayed in place you should have no adhesive visible on the fabric itself.
Leave it clamped for at least 4 hours, longer if possible.
I wrote this guide the day after I did my own roof, time will tell if it has worked. It should look like this.
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for doing this!
