Build Status: Complete
Words & Pics: Grrrmachine
Contact Owner: E30zone Profile
The car needs a respray, so I’m rust hunting. Took off the driver’s wing (LHD) expecting it to be bad, and wasn’t quite prepared for this level of damage…
I’ve got a good section chopped out of a donor vehicle, although it’s not quite long enough; it doesn’t run all the way up to the bulkhead.
I’ve done some more tentative cutting, and the rot hasn’t QUITE got to the wiring loom hole. However, it spreads inside from that seam, so that the triangle box section (under the scuttle, above the glovebox hinge if I had one) is also rotten.
I guess I’m going to have to cut out the fuse box mount, and the flat bit behind it, just to see what’s down there…
Right, I’ve spent the afternoon cutting back to assess the damage. Angle grinders with slit discs, and the dremel, have been a godsend:
As you can see, the worst of it was under the fuse box, but I think I can patch the layers in fairly easily, considering most of the inner wing is already missing.
But my new worry is the seam between the inner wing and the bulkhead, as it runs down under the brake servo:
It’s only spot-welded, but it’s got rust all the way down to the chassis leg. Mostly surface rust, but one or two pinholes too. Not sure how to attack that.
The seam isn’t actually that bad. Considering a lot of the inner wing is coming off, I made a cut about half an inch from the seam, half way down, and seperated the wing from the bulkhead. Then I cut out the little bits of rust that were bad, and cleaned up the rest with a wire brush on the Dremel.
Once the bulkhead is all patched up, I’ll join the inner wing back to it along this original seam before cutting anything further.
Well, the first repair patch went in today:
I haven’t taken a picture of the welding because it’s awful (since I’m a novice) but the penetration looks alright from the footwell on the other side, so I’m happy.
This rust was caused by the sealant BMW pumped into the A-pillar. It spilled out and settled in the seam under the scuttle, acting as a moisture trap. I’m sure quite a few E30s have this under the fuse box, hidden by the scuttle.
The biggest fear for me was loom damage, followed by fire. Because the dash is still in, the sound insulation was at risk so I inserted some sheet steel offcuts behind the welding, and welded from the engine bay. Melting underseal stinks, but apart from that there were no issues.
Getting the bulkhead/footwell solid is the current priority, then I can rejoin the inner wing to good metal.
I tackled some of the bulkhead today:
This part sits just behind the plastic arch liner, and had one of the mounting holes which had long since rotted away.
So, cut the infected area out:
Make up two patch panels (one to repair the bulkhead, one to extend the arch outwards) and line them up for fitting:
And then start laying down snotty little blobs of weld to hold it all together:
I didn’t quite get the chance to weld in the second of the two panels, but it’s beaten into shape and the holes have been drilled to plug-weld the two edges together, similar to the original seam that had rotted away. I used a massive strip of copper (50x5mm) behind the panel to take heat away as I welded, and also to help me fill the gaps from my less-than-perfect patch forming.
Right, that’s all the repairs under the fuse box taken care of. For those that come across rust in this place, here’s the deal:
Cut it all out through both skins (scuttle and bulkhead). You will have to slice off the bracket for the fuse box too.
Weld in the repair panel for the bulkhead (I did do it properly, this is just a few clumsy tacks)
Weld in the repair panel for the scuttle, with plug welds in place of spot welds at the bottom.
Understand how the two plates make a triangle drain, so that water that enters the wiper grill holes can run out through the inner wing. Note the bulkhead repair has been sprayed with zinc-rich primer.
If you remove the windscreen wiper grill, you can access the area behind the scuttle. This will be necessary, because the waxy anti-rust BMW use, and their seam sealant, are flammable, so scraping as much away as possible reduces smoke and flames in the area.
This repair was done with the dash and wiring loom still in place, although I did insert off-cuts of steel between the bulkhead and the sound-proofing on the inside, to remove heat and to reduce the risk of smoke and fire. I also bent some aluminium into a “sleeve” to wrap around the loom, to protect it from weld spits and grinding sparks.
In order to get the bottom edge flush so that the plug welds were solid, I had to use a long length of copper against the inner wing, and a crowbar to push the edge of the repair plate flush. So one hand pulled the crowbar from above, the other hand did the plug welds. Turned out pretty well, considering!
And a final long strip to rejoin the inner wing to the bulkhead. Made of 1mm steel, it took me quite a few hours to bash and grind this thing to shape, but it went in eventually. I took the pictures half way through welding, while things were cooling down. It helps get your patience back when you’ve blown a few holes in the metal.
Showing how the inner wing abuts the scuttle.
View from underneath. I did put plug welds in, but having read another thread about stitching all seams, I figured I’d take the opportunity to join these ones too, for extra strength.
The welds penetrated pretty well, but I welded both sides where I could, just to be on the safe side. The next step is to tidy up all the little holes I’ve left in the bulkhead, then I can chop out the rust around the suspension turret and put a new inner wing support on…
Today’s progress involved cutting out the rust and preparing the replacement panel for the suspension turret.
However, the turret itself turned out to be fine, once the rusty layer of the inner wing was cut away.
On the E30, the turret comes down to a horizontal support plate, onto which the inner wing is spot welded.
All the old spot welds were ground off and chiselled away to make a smooth surface for the patch plate, which I scavenged from a donor vehicle. Well, not a whole vehicle, I bought a front quarter of a car for about 20quid, for precisely this purpose.
Then the plate was trimmed, filed and offered up until it lined up snuggly with the hole.
The downside of this is that chiselling the piece out of the donor introduced quite a few dents and bumps which will take some planishing to smooth out. On the upside, the donor was exactly the same colour as the car, and although the whole thing will get a paint job later anyway, it’s just that little bit more satisfying.
Now the slow job of butt-welding the piece in, plus the plug-welds to hold it onto the suspension turret.