Project Coomadore rust repairs - Our Shed

Date: 18.11.2022

Glenn Torrens gets a-beatin’ and a-weldin’ on his wrecker-rescued Commodore’s rusted and busted bits

Like many decades-old cars, my rescued-from-a-wrecking-yard 1981 VC Holden Commodore had some rust. The worst of it was in the spare tyre drop-down, a common problem area for Commodores. There was also a palm-sized patch of rust on the driver’s side rear quarter – another typical rot-spot for these early Commodores - so the Saturday after I bought the car and brought it home from buying it, I got to work.

Luckily for me, the rust in the spare tyre area hadn’t spread elsewhere so the repair would be easy using a bought-in patch panel from one of several suppliers.

Unluckily for me, this patch panel wasn’t available anywhere. On-line searches and phone calls to the usual suppliers all gave me the same answer: ‘Nil Stock’; ‘Back Order’; ‘Sold Out’… One bloke I spoke to mentioned he wasn’t expecting stock to arrive for another three months!

Damn! That was disappointing as I didn’t want to wait for three months to be cruising in my resurrected Commodore!

Then I had an idea: Maybe a section cut from an old VW Beetle mudguard could possibly be reshaped and grafted in...? I had a few crappy old dak-dak panels laying around – and nothing to lose by trying!

The first thing I did was neatly cut out the rusty section from the Commodore. Then I ‘matched’ its curve to a Bug guard as a starting point for hand-making a repair section.

The Commodore spare tyre drop-down is not perfectly curved and it has an indent at its base. Why? Dunno. However, by panel-beating the VW guard (I learned some panel basics by doing an enthusiasts’ course at my local TAFE college a few years ago) I was able to roughly replicate this indent.

When I was happy with the basic shape, I cut up the VW guard and with a bit more hammer/fitting work, I fitted and then welded in my custom-made rust repair section to the Commodore’s spare tyre aperture. Yay!

This VW Bug front guard was a good starting point for my spare tyre area fix: I beat in the factory-type dimple in its base, then cut and fettled the section to fit the car

Other areas of the car – under the front guards, the battery tray and the boot floor – had nothing more than minor surface rust. Here, I simply wire-brushed, treated with rust killer, and then primed and painted. Prior to a splash of paint, I reapplied seam sealer to the edges of the boot floor and to the plenum ends.

Another less obvious repair I did to my Commodore was to the underside of the bonnet and boot-lid. These panels are constructed with the outer skin spot-welded to an underside frame, with a few dabs of adhesive applied between. This adhesive degrades and eventually falls out, leaving the panels ‘loose’.

The result is a bonnet and boot-lid that clang and make a horrible din when the car is driven, especially on rougher roads. A fresh application of body sealer/adhesive between the skins and the frames kills the clang, making the car noticeably quieter in the cabin.

Another area I gave some attention to was the plenum at the base of the windscreen. Here, on each side, several welded joins were finished by the factory with seam sealer. After four decades the sealer is often flaky, allowing water to invade the joins and cause rust. If the rust isn’t too bad, the fix is relatively easy: crack/scrape off the old seam sealer, neutralise any surface rust and apply fresh seam sealer and paint, as I did.

With the rust and other minor bodywork completed, I carefully reassembled the front guards (making sure I didn’t damage that lovely lichen!) and fitted a good second-hand pair of headlights. I also installed a slightly daggy front bumper to replace the missing one.

1. Commodores suffer rust under the screen rubbers and adjacent to the front guards’ top and bottom corners. I primed and painted it so it will remain tidy for another 40 years.

2. With the body repaired over a relaxing couple of weeks of evenings and part-time days, my resurrected Commodore is one step closer to being ready for the road!

3. I poked a garden hose into the inside of the sills: about half a kilo of this Aussie outback dirt came out of each side. It can cause car-killing rust

4. The battery tray – a common Commodore rust area – wasn’t bad: As with some other parts of the car, it was wire-brushed and treated with rust-kill before prime ‘n paint.

5. The original headlights were unusable due to corroded reflectors and lichen on the glass, so I found and fitted a good second-hand pair.

6. The boot floor looks disgraceful – but most of that is rusty dust: only a few small holes needed attention

7. The boot seal channel had minor rust; it was prepped, primed and painted with marine-spec epoxy paint

From Unique Cars #471, Oct/Nov 2022

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