djaychela
New member
OK, thought I'd put my take on this. I have an '82 944 which I like a lot, but it's clearly been owned by some bodging morons in the past. I am certainly not anal about cars in terms of originality, but I do like them to be functional and well maintained in the areas that matter (I guess that's why I do what I do in my other car), and this car leaked. Not a bit, but a lot!. However, I didn't know why, so first was to find out where the water was coming in. This was tested easily enough with a helper and a hose while I was in the back of the car - the water was coming in in three main areas - along the top of the glass (where the tailgate hinges are), and also the bottom corners, under the spoiler. It wasn't just seeping in, it was flowing in really quickly. Once the car had dried out, I opened the hatch and twisting it slightly showed the extent of the separation between glass and frame - none of the top was attached at all, it was moving freely. The sides were bonded OK, but again the bottom edge was loose at either corner.
Obviously, this is a fairly well-known issue, and I'd seen a few US-based guides on how to fix it, so I set about it. Firstly, the spoiler needs to be removed - no mean feat with screws which were rusted in place, but most of them came out, with the two end ones (M4) and two of the main mountings (M5) snapping off. Then the side trims, held in place with slotted round nuts - a lot of people had complained that these were difficult to get off, but slotting a screwdriver with a few hacksaw cuts saw a tool which removed them easily. It was now apparent just how much of the bond had come away - the bottom corners were loose for about 8" along the bottom on each side, and it was easy to see daylight in the gap. It was also apparent that the last owner(s) were idiots. I found a total of FIVE different substances which had been shoved under the spoiler and trim to 'seal' it, including BITUMEN (no, really), and a white sort of chewing-gum-like substance.
What isn't made clear in some of the guides is the amount of time that is needed to remove the glass - it took me FOUR hours of solid work without a break to get it out; most of this was done with the hatch in situ, but to remove the top piece of trim (that covers the frame and the sealer, along the roofline) means the hatch needs to come off. Once this is done it is easy enough to prise out with a screwdriver, to carry on the removal. To get the glass away from the frame was mostly done with a stanley knife, a sharpened palette knife, and in a couple of places (by the hatch strut mountings) using a guitar string as a "saw" - although you can buy wire to do this job better, it was a Saturday and I wanted to get on with it. I've broken toughened glass before - it will only take a certain amount of strain before it gives way, so it's important to take it easy as another piece of glass will be at best £50 secondhand in a frame, and you'll still need to remove it given the condition of most secondhand ones!
Once the glass is out, you may think that that the job is over, but it's not! The reason is that the failure apparently comes from the black surround which is painted onto the glass; this provides UV shielding for the sealer, and it failing leads to the sealer failing. So all of this and the old sealer needs to come off. This took me about 3 hours - some places it was dead easy, but others it was hard work. However, eventually the glass was totally clean and ready.
Next, the frame - the sealer had stuck properly in many places, and was difficult to remove by hand, but I removed it a lot quicker by using a flapper wheel in a grinder - the sealer will stick well to the fresh, rough aluminium that is left by it, and there were several areas where the aluminium had corroded with water ingress:
This needed a considerable amount of dressing back to get it clean, but it was important to do so properly.
The final stage before refitting the hatch to the glass was to straighten out the warping of it; most of this had been over the years, but also some happened while removing the glass. To do this, I turned the glass upside-down, and then trial fitted it, bending the frame (carefully!) to get it to sit properly on the glass with as many areas as possible in contact. It was also time to notice how the glass would align on the frame - there is some leeway which would mean the spoiler holes would be covered up with glass, which clearly wouldn't be good (plus the top run wouldn't be anywhere near where it should be if that was the case), so worth getting acquainted with how it would go.
Next, the bonding! For this I had bought a kit on eBay, of PU sealer, plus glass adhesion promoter and black primer - it was about £15 for the kit, but I bought more black primer as the 30ml which comes with it wouldn't be enough for the considerable area needed due to the wide black area under the spoiler, so that was another £15 from the same company. The black area needed to be masked off (about 50mm wide at the bottom, 20mm everywhere else)
The adhesion promoter was applied, followed by the black primer. This needs to be left long enough to dry, but less than 3 hours to maximise adhesion.
Now, the messy bit, potentially, applying the sealer. This stuff is HIDEOUS. I have had several friends who've been windscreen fitters for some time, and all of them hate the stuff - if you get it anywhere it sticks like you wouldn't believe. You need to wear gloves, and ensure you don't get it anywhere you don't want it to, as you won't get it off easily. I piped a generous bead all the way round the frame (taking care of the positioning as the bottom run by the spoiler holes needs to be in a different place whereas all the other is nearer the outside), and then it was the big moment, dropping the frame onto the glass. This was done with help, and then guided where it should be; spring clamps were used to hold it in place as it's best to leave it for 24 hours for it to set. After 10 minutes or so the sealer skins off, and it's possible to trim with a sharp blade any excess - bear in mind that doing it now will be a lot easier than doing it when it's set.
To make sure it was bonded fully, I ran another small bead round the inside of the frame, and also filled the outside between the spoiler holes (like the OEM fitting), and left it for another day.
After all that, it's fairly easy to refit - just refit the top trim before fitting the tailgate, and everything else will bolt in place. The snapped off screws needed to be drilled out and then retapped, and I replaced all the screws with new, plus the boot pins as they were seized solid and even 24 hours soaking in penetrating fluid did nothing to help.
Doing it has done two things - firstly, it means the car is now watertight - even the most intensive hosing leads not a single drop to get into the car at the back. But the difference in the feel of the tailgate is incredible - it feels really solid compared to the flexible, flimsy thing it was before.
Total cost £30. Total time, about 9 hours. I guess you could put a brick through it and claim on your insurance, but even if you did do this, I really can't see a windscreen company making as good a job in terms of frame preparation, and the corrosion was the main reason the bottoms had come away, so not worth taking a shortcut there, for sure.
Obviously, this is a fairly well-known issue, and I'd seen a few US-based guides on how to fix it, so I set about it. Firstly, the spoiler needs to be removed - no mean feat with screws which were rusted in place, but most of them came out, with the two end ones (M4) and two of the main mountings (M5) snapping off. Then the side trims, held in place with slotted round nuts - a lot of people had complained that these were difficult to get off, but slotting a screwdriver with a few hacksaw cuts saw a tool which removed them easily. It was now apparent just how much of the bond had come away - the bottom corners were loose for about 8" along the bottom on each side, and it was easy to see daylight in the gap. It was also apparent that the last owner(s) were idiots. I found a total of FIVE different substances which had been shoved under the spoiler and trim to 'seal' it, including BITUMEN (no, really), and a white sort of chewing-gum-like substance.
What isn't made clear in some of the guides is the amount of time that is needed to remove the glass - it took me FOUR hours of solid work without a break to get it out; most of this was done with the hatch in situ, but to remove the top piece of trim (that covers the frame and the sealer, along the roofline) means the hatch needs to come off. Once this is done it is easy enough to prise out with a screwdriver, to carry on the removal. To get the glass away from the frame was mostly done with a stanley knife, a sharpened palette knife, and in a couple of places (by the hatch strut mountings) using a guitar string as a "saw" - although you can buy wire to do this job better, it was a Saturday and I wanted to get on with it. I've broken toughened glass before - it will only take a certain amount of strain before it gives way, so it's important to take it easy as another piece of glass will be at best £50 secondhand in a frame, and you'll still need to remove it given the condition of most secondhand ones!
Once the glass is out, you may think that that the job is over, but it's not! The reason is that the failure apparently comes from the black surround which is painted onto the glass; this provides UV shielding for the sealer, and it failing leads to the sealer failing. So all of this and the old sealer needs to come off. This took me about 3 hours - some places it was dead easy, but others it was hard work. However, eventually the glass was totally clean and ready.
Next, the frame - the sealer had stuck properly in many places, and was difficult to remove by hand, but I removed it a lot quicker by using a flapper wheel in a grinder - the sealer will stick well to the fresh, rough aluminium that is left by it, and there were several areas where the aluminium had corroded with water ingress:
This needed a considerable amount of dressing back to get it clean, but it was important to do so properly.
The final stage before refitting the hatch to the glass was to straighten out the warping of it; most of this had been over the years, but also some happened while removing the glass. To do this, I turned the glass upside-down, and then trial fitted it, bending the frame (carefully!) to get it to sit properly on the glass with as many areas as possible in contact. It was also time to notice how the glass would align on the frame - there is some leeway which would mean the spoiler holes would be covered up with glass, which clearly wouldn't be good (plus the top run wouldn't be anywhere near where it should be if that was the case), so worth getting acquainted with how it would go.
Next, the bonding! For this I had bought a kit on eBay, of PU sealer, plus glass adhesion promoter and black primer - it was about £15 for the kit, but I bought more black primer as the 30ml which comes with it wouldn't be enough for the considerable area needed due to the wide black area under the spoiler, so that was another £15 from the same company. The black area needed to be masked off (about 50mm wide at the bottom, 20mm everywhere else)
The adhesion promoter was applied, followed by the black primer. This needs to be left long enough to dry, but less than 3 hours to maximise adhesion.
Now, the messy bit, potentially, applying the sealer. This stuff is HIDEOUS. I have had several friends who've been windscreen fitters for some time, and all of them hate the stuff - if you get it anywhere it sticks like you wouldn't believe. You need to wear gloves, and ensure you don't get it anywhere you don't want it to, as you won't get it off easily. I piped a generous bead all the way round the frame (taking care of the positioning as the bottom run by the spoiler holes needs to be in a different place whereas all the other is nearer the outside), and then it was the big moment, dropping the frame onto the glass. This was done with help, and then guided where it should be; spring clamps were used to hold it in place as it's best to leave it for 24 hours for it to set. After 10 minutes or so the sealer skins off, and it's possible to trim with a sharp blade any excess - bear in mind that doing it now will be a lot easier than doing it when it's set.
To make sure it was bonded fully, I ran another small bead round the inside of the frame, and also filled the outside between the spoiler holes (like the OEM fitting), and left it for another day.
After all that, it's fairly easy to refit - just refit the top trim before fitting the tailgate, and everything else will bolt in place. The snapped off screws needed to be drilled out and then retapped, and I replaced all the screws with new, plus the boot pins as they were seized solid and even 24 hours soaking in penetrating fluid did nothing to help.
Doing it has done two things - firstly, it means the car is now watertight - even the most intensive hosing leads not a single drop to get into the car at the back. But the difference in the feel of the tailgate is incredible - it feels really solid compared to the flexible, flimsy thing it was before.
Total cost £30. Total time, about 9 hours. I guess you could put a brick through it and claim on your insurance, but even if you did do this, I really can't see a windscreen company making as good a job in terms of frame preparation, and the corrosion was the main reason the bottoms had come away, so not worth taking a shortcut there, for sure.
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