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A-pillar rust :(

Posted: Wed Oct 13, 2010 9:56 pm
by Nuffles
...strangely enough, however not in the usual place. I knew the driver's door was sagging when I bought the car but thought it would be a simple weld job around the upper hinge. The sagging has been getting worse recently so with some free time this afternoon I whipped (bit of a misnomer that one) off the wing and checked things out. The top of the A-pillar is in sterling condition with no rust at all and a nice metallicky ring when you tap it. The bottom of the A-pillar is a different story, however. The first sign of a problem was that once all the bolts were off the wing still wouldn't come free and it was discovered that the bottom seam where the two bolts secure the wing had rusted through so some pillock had welded the wing to the A-pillar. Thankfully the rust was far enough advanced that some nifty work with a flat headed screw driver and a mallet soon had the wing free. With this off, however, everything was revealed.
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This, rather sizeable hole, is what's allowing the bottom hinge to flex forwards (rather than the top hinge, back) allowing the door to sag. The tab on the wheel arch next to the upper, lower bolts is where the wing was welded too. The weld went further down but we broke the metal off getting the wing off. Unfortunately, you can see that the rust is creeping up the wheel arch lining...
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Yep, it's crept right the way up to about 7 inches behind the bumpstop. I could see this even with the wing on but assumed it was a non structural part and not connected to the A-pillar. Now I understand that I'll have to grind out this whole section to put in a new piece. How thick steel should I use for patching? 2mm? 3mm?
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This is the hole in detail, the second, smaller hole being as far upwards as the rust goes. About an inch above that is totally solid metal. I guess I grind the whole way around, and right up the arch liner? We have a local village blacksmith that will make up anything I create a pattern for so actually getting the plate will be cheap and easy, but I'm just wondering about the finer stuff. Would I be best off with a patch slightly larger than the hole (say about a cm all the way around) and welding around the circumference? Or should I set the patch flush with the metal and again weld around. The former, I imagine from my limited welding experience, would be stronger but I could well be wrong. It's not an area on show so I'd prefer strength over prettiness really. Any ideas?

This is the pile of rust/dirt that I managed to scrape out from the bottom of the A-pillar:
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Bad times. So just general tips please guys, as this is the first welding work I'll have done on my Moggy.

Re: A-pillar rust :(

Posted: Wed Oct 13, 2010 11:02 pm
by bmcecosse
You need to cut away all the rot - back to good clean metal. Even 1mm steel will be far too thick - somewhere around 0.5mm I suspect will be thicker/stronger than the original steel.

Re: A-pillar rust :(

Posted: Thu Oct 14, 2010 7:53 am
by kennatt
as bmc says get rid of all the rusty metal,and weld from the inside outwards to the outermost panel,IE when you get the metal off there Will be rust on the inner framework,make very sure that the door lines up before welding up because once its welded no way of rectifying a missaligned hinge.Very typical rust damage,there will be many out there with the same hidden rot,unfortunately you can't see it without taking the wings off. Good luck with it

Re: A-pillar rust :(

Posted: Thu Oct 14, 2010 8:38 am
by Nuffles
Thanks for the tips, yeah I'd gotten as far in my mind as supporting the door with a jack while welding to make sure it's at the right height as it sags a little even when closed. So it's really just a case of keep on cutting back till I hit solid metal and go from there? I was going to make a template today before I put the wing back on to take over to the blacksmiths so I'll make it bigger than needed and grind off what I don't need. Ill get a second plate cut too for anything inside this (I can see some small holes even now) and cut that to size with the grinder when needed. This is the last of the rust for now, except some panel rust in the wings, so the car will be solid once this is sorted. Thanks again.

Re: A-pillar rust :(

Posted: Thu Oct 14, 2010 9:27 am
by mogbob
Remember there are several "repair"section panels available from the main suppliers for typical rot areas ( and yours is typical ), e.g RP124R which incorporates the captive nuts to fix the wing back properly.
If you are doing the repairs from flat sheet metal, dont forget to weld nuts on the reverse side before you fix to car.Exact location is obviously crucial if you don't want problems with wing fixing later.
The decision on repair panels is :- how deep is your wallet, how easy is fabrication, time and skill to replicate the piece compared to simply cutting off the " excess metal on the repair panel you don't need ".

As it's your first bash, think about the reverse of "painting yourself out of a room ", i.e. do the inner most bits whilst access
is good and work out to the exterior to finish off.Clamp everything up tight and double check your measurements before tacking with weld.Check again and then go for it.

Bob

Re: A-pillar rust :(

Posted: Thu Oct 14, 2010 4:31 pm
by chickenjohn
I disagree with BMC. Patch repairs on the inner wing should be 1mm or 0.8/0.9 at the very least, this is a classic 60's car not a thin tin modern, and the Sill sections and A pillar should be 1.2mm.

If I were you on such an important area of the car, replace as much as you can with repair sections and butt weld rather than overlap. Cut off the A pillar cover dome (the bit hidden by the wing) and see how bad the inside of the A pillar is. If it is all thick rust then you might be better off with a whole new A pillar as well as the rear part of the inner wing and once the inner wing is off, repairs to the kidney panel area are not unusual either. Best to repair it all properly rather than be tempted to patch over with lap welds and hide the problem.

A pillars are tricky to fit as you have to ensure the door still opens and closes and the gaps are still good. Before cutting anything, bolt the front wing back on in the right place and measure all the panel gaps around the door, i.e between door and wing top and bottom and door and b pillar. You will then know what to aim for.

I trust you can weld and fabricate?? If not then either take it to someone who can, or go on a restoration course, these excellent courses are starting their first evening class sessions at this time of year.

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 7:38 am
by Nuffles
I did some quite extensive welding with several kinds of welders at college so I've had a bit of experience - enough to make a strong weld. I wouldn't say I was a 'fabricator' as such but I can make things the right shape and size without too much trouble, but as I said, the local blacksmiths will be taking care of the actual fabrication bit. I was going to go for 1mm anyway, and fully intended to cut all the rust out first. From what I can see, there is some rust on the panel behind the one in question but it's localised to a small area at the bottom of the panel and in nowhere near as bad a condition as the front panel.

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 5:49 pm
by taupe
Another tip if youre going to make your own repair panels is to make a paper template of the panel first before cutting out.

You should ideally cut out all the rusty steel back to good sound metal - especially if mig welding.

1mm thick at least for this repair.

You will probably also find the inner wheelarch is quite corroded where the water has got in through that crack :(

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 6:17 pm
by bmcecosse
I'm very sure the original panels (and any repair sections you buy now) won't be 40 thou (= 1mm) thick!

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 6:37 pm
by chickenjohn
bmcecosse wrote:I'm very sure the original panels (and any repair sections you buy now) won't be 40 thou (= 1mm) thick!
You're right, they are usually 0.9mm! :wink:

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 6:40 pm
by d_harris
I agree with John. Its far better to make it overly strong than risk it being too weak.

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 6:43 pm
by taupe
No BMC

Ive just measured one with a vernier caliper the flitch panel is 1.02mm 20swg

Taupe

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 8:59 pm
by bmcecosse
Wow! I'm amazed!! Thanks for doing the measure!

Re: A-pillar rust :(

Posted: Fri Oct 15, 2010 10:36 pm
by chickenjohn
Yes! Minors are made of sturdy stuff, the inner sill is~ 2mm thick, for example.