Project Marina, Underside Tidy Up

After the bitter disappointment of the failed “WOF” I’ve been non-stop working on plans to move forward, and yesterday I put the first of these into action.

The main thing that stopped the WOF in its tracks was the underside of the car. I was told the underseal had to be completely stripped off, and all surface rust had to be removed. The easiest solution was to “go talk to such and such” and have it sandblasted, treated and recoated.

Now, if this was for a re-registration inspection for a car that was de-registered (like the Mini was), this is a request that can be made if the inspector has a reason to suspect the underseal is hiding something like rust. Ironically, the underside of the Mini was coated in the exact same underseal, and flew through re-rego check.

For a standard WOF, for a car that doesn’t need re-rego (the Marina rego has been on hold for almost 30 years, thanks previous owner!), this request is way out of the scope of an inspection unless the whole car looks like its been under the sea (which happens occasionally).

The Marina is neither de-reg, nor does it look like it’s been under the sea.

I didn’t call the guy the WOF man was recommending, but instead spoke to a very helpful chap at a local sandblasters, who is known for doing work like this on cars that are rusty underneath.

His opinion was that it was best not to touch the underseal and to leave it as is as it was still doing its job. Removing the whole lot would be a huge amount of work, since the tar-based stuff is meant to absorb impact and deflect things like stones, sandblasting wouldn’t really strip it. He couldn’t think of any reason someone would want to strip the whole lot off, unless it was a full resto, and needed to go back to bare metal. After a good chat with him, I felt confident in my next move.

Despite having seen it briefly on the hoist during the WOF when I asked to be shown what the issue was, I had built up a far worse picture in my mind of what it looked like under there. The only thing for it was to grab a scraper, a wire wheel, and roll under the car and have a look myself.

For the first time, I put a car up in the air on my really old, really solid screw type jack stands. These go higher than my usual ratcheting type, and I needed all the height I could get.

I took the wheels off and went for a tour with my torch.

This is the surface rust at the front. He made it sound like this was life threatening and an absolute horror. It’s the underside of the battery tray, welded to the inner guard. I wire brushed and treated this with Brunox.

One thing I will agree on is that I didn’t do a very good job of cleaning the old rust flakes out of the chassis rails when I replaced the rear valance and floors. I blew it out with a compressor a bit from the top, but clearly I just moved it around and some of the flakes were too big to even come out the holes.

That was entirely my own doing, so I’ll own that.

In terms of the underseal, I spent ages under the car poking around. These are the worst areas I could find

The worst areas, the last two photos, are in direct proximity to the muffler and it looks like the heat from that actually dried out and cooked the underseal.

Beyond that, the underseal although dirty, is actually in really good shape. it’s stuck on well, still soft and doing its job.

I started with the nasty job of wire wheeling all the loose and flaky underseal off. I was going to use a scraper, but it didn’t touch even the flakiest bits. The wire wheel did a good job on the dry stuff, but barely touched the areas around it where the underseal was still nice and soft. I’d hate to try and actually remove the whole lot. No photos of this, it was super messy and I was trying to just get it done.

Once it was all cleaned back, I coated all the areas in Brunox, a rust converter and treater. This should stop any surface rust from creeping back. This was step one.

While the Brunox was doing its thing, I changed to clearing out the rails of flakes. I did this with a combo of my air compressor and a long flexible magnet.

Stick the magnet in the helpfully placed holes and go fishing

It would come back with a nice little collection of crust. Rinse and repeat.

Using an air gun I blew as much of the smaller stuff as I could out the holes in the rails, from all directions, and then using a combo of air and the magnet, caught anything else that was left. The magnet was good for smashing up the bigger bits too.

It was a long, messy job, but I ended up with some nice clean holes

This is what happens when you fit a towbar and don’t use crush tubes

Since it’d been a couple of hours now, the Brunox was nice and dry and ready for me to give it a coating of black zinc paint. This will also help to protect against any future rust.

While that dried, I moved on to the big bad rust inside the boot

It’s a prick of an area to actually work on without removing the boot hinges, so I had the bright idea to try my soda blaster on it. This is a cheap gun, on a compressor that’s far too small, and firing baking soda at it under pressure. I didn’t expect much, but I had everything already so it cost me nothing.

It’s not perfect, but it knocked the lighter rust clean off and the deeper rust cleaned off so the Brunox will be able to work on it. I treated the rust with Brunox and then coated it in black zinc to seal it.

Finally, we were back to the underside again. I finished the job by giving everything a nice fresh coat of underseal. Because the new underseal is pretty flat, it’s obvious it’s not hiding anything, but seals and protects everything. Its looking 100% better.