The angle grinder is out as we cut into the roof to remove the worrying rot above the nearside load bay window.
We introduced our Austin Montego estate last issue, and assessed its viability as a project. It was not an auspicious beginning, with calculations on the back of the proverbial fag packet suggesting it could cost anywhere from £5000 to £10,000 to put right. That is a huge amount of money for such an unfashionable classic. It is also rather vague with a very wide spread, but bodywork estimates are never an exact science and really there is no way of making a truly accurate estimate until you are well into the dismantling process.
Thankfully, despite the fact that this project was clearly not going to be economically viable, the publisher was still keen to save the Austin if we could. So we agreed a plan to tackle one job at a time and assess our progress at each step.
As such, it made sense to begin with the most daunting repair – where the roof had rusted out above the nearside window to the load bay. We were not really sure why it should have rusted so badly in this particular area, but somebody had been there before us with what could most politely be called ‘temporary repairs,’ so it is always possible that a relatively minor problem grew into something more serious
We make a start on the body repairs to our rather forlorn Montego estate, knowing that if this first cut reveals anything too horrific, the project could well be over before it has really begun.
REPORT: SIMON GOLDSWORTHY
under the body filler.
However, on a car of this vintage, it is not really the metal that is the biggest concern. Of course, as we have already noted there is a limit to how much rust damage you want to tackle, and also how much you want to pay if a specialist is doing the work for you, but as Alan Denne who is doing the bodywork repairs for us says: ‘It doesn’t matter if it is a Montego or a Ferrari, at the end of the day it is only metal.’
The bigger problem is that in the 1980s BL was making wide use of plastics, and some 40 years later these tend to be brittle and are now almost impossible to replace with new or used parts. On the plus side, this will no doubt afford us the opportunity later in the series of showing how we resolved problems that simply don’t arise on something like a Morris Minor. For now though, I’ll stop wittering on and let the pictures show just what lay under that ominous looking rot in the roof.
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This is the worst looking part of the car, and so the first area of rust that we wanted to tackle – on the nearside above the rear side window and into the roof. As you can see, it has been previously covered up with silver tape and filler.
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Once the retaining plugs had also been removed from the headlining and the assembly released from these three clips across the top of the tailgate opening, it should drop down. Ours didn’t because it had been glued across the back.
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Before wading in with the cutting disc, we had to remove various bits of interior trim that might otherwise get damaged in the repair process. That started with taking off the interior lights, handles etc from the headlining.
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With other interior trim removed too, we could start our investigation of the roof rot. The gutter trim was brittle plastic and it snapped in two places when we removed it, but we will be able to glue it back together.
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It had also been glued across all of the strengthening ribs under the roof panel. We used a thin scraper to cut through as much of the adhesive as possible while trying to minimise any damage to the liner’s backing board.
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The cloth on this was in decent shape, so we were pleased to get the whole roof lining out intact – a job made easier thanks to the estate’s rear door. The board was not damp or crumbling either, surprising given the rust damage on the roof.
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We then tried a small cutting disc in the Dremel from the inside, which worked in theory but the mastic provided too much grip for the tool to keep spinning for more than a few seconds. It was a similar issue with this metal cutter.
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We had to remove the C- pillar trim so that we could remove the side window to the load bay to provide full access to the rust. However, our big problem then was how to get the window out, as these are bonded in on a Montego.
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Now we could dig out the filler and silver tape that had been used to plug the rot. Part of the gutter itself came away too, but fortunately there is a natural break in this by the C- pillar, and ahead of this point, all is sound metal.
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First we tried using a hacksaw blade. It cut the mastic, but the blade had to be bent to keep it away from the glass and metal, and once we reached the end of the section where the gutter had been removed, the bodywork got in the way.
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Next, Simon bought this bespoke tool. It was only £7, and he did not have high hopes of its efficacy but thought it would be interesting to try. Sure enough, the blade could be pushed into the mastic, but it was simply not sharp enough to be pulled along and keep on cutting.
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It looked a little Heath Robinson, but with Simon pulling on the handle from inside the car and Alan holding onto the reel and then pulling the wire back from the outside, the wire cut its way slowly through the mastic, avoiding the metal and not damaging the glass.
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Finally he splashed out £16 on this roll of square section cutting wire, essentially a ‘cheese wire’ that is intended for this very automotive task. He also dug out an old pad saw handle from the garage, and swapped the blade in this for one end of the wire.
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For now though, the remains of the old mastic were cut away so they could get to the metal beneath. You’ll notice that by this stage, Alan had also cut the rusted section of the gutter and the roof panel away to reveal the box section beneath.
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Success – they got the glass out without it shattering. They will have to figure out how to reattach it afterwards, but that is a job for later. So is replacing some of those plastic trim clips on the window surround trim.
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The plan was to first replace the outer face of the box section (the green line on the previous picture), then plug weld the drip rail (red line) to this. The roof section (blue) will then be the final part of the puzzle to be welded on.
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You will not be surprised to learn that repair sections for Montego roofs are not readily available! For the box section, Alan transferred his measurements of the rusty metal to a sheet of flat steel and cut that out.
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When Alan was finally happy that the folds of his new repair section were at the correct angles and to the right depths, he straightened up the flanges using a hammer and dolly. This will all be hidden, but it has to be a good fit.
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It might be a little primitive, but this drawing will hopefully show what they were up against. The blue is the roof panel, while the red is the gutter drip rail. The green and pink represent the box section under the roof.
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There was much to- ing and fro- ing between the vice and the car to check the profile as it developed, with tweaking to the folds as required. Note that the repair section is still oversize at this stage – don’t be too hasty to cut it!
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Clamping the piece of sheet steel between some angle iron in a bench vice, he knocked the fold lines in using a bolster chisel that had been ground to give a rounded end rather than a sharp one.
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There was a curious white pipe inside the box section, which turned out to be the screenwash pipe to the wiper on the tailgate – we couldn’t see any nozzle at first, but finally found it incorporated into the wiper spindle.
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Alan then sanded back the flange on the car to reveal the spot welds. There were not many, only about every three inches. Alan’s spot weld cutter was never much good, and he often uses a regular drill bit that he has reprofiled to make it flatter.
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Next he cut along the top, but below the line where he expects to end up, and also horizontally above the swage line and vertically at either end so that the bulk of the metal could be removed. And yes, he should be wearing protective gloves!
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In a similar manner, he made up this complicated shape that will replace the rotted- out drip rail (the red bit on our drawing in step 16). Fortunately this does not feature any extra curves at this point on the estate’s roof, but is a straight line.
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Alan then tried prying off the flange, but the spot welds were still gripping so rather than risk distorting the flange behind that we want to reuse, he resorted to the angle grinder and then a thin chisel.
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The final step before reaching for the welder was to clean up the flange on the inner part of the box section (the pink line from step 16). Note how totally rustfree the box section is on the inside.