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How-To Restore Floorpan: Brace and Protect (P2)

This month, Project 13/30 gets the floors painted and the subframes connected.

(Words and Photos: Dave Smith, American Car Magazine, March 2016 issue)

eastwood extreme chassis black frost auto

Last month, we left Project 13/30 on its side with primer and seam sealer all over the underside, so let's take over from there. With the primer and seam-sealer all dry, it was time for the topcoat, Eastwood's Extreme Chassis Black (1). This stuff claims to be three times more durable than regular chassis blacks, and again comes thinned for spraying, so after a good stirring it went straight into the gun.

The first coat went on beautifully, although it didn't quite cover up the seam-sealer (2). I turned the shell 180 degrees on its spit to make sure I didn't miss any bits, and laid down the second coat, which did cover it (3). Somehow, there was still enough left out of two US quart tins to give a third coat and still have a bit left over for touching in. The finish was exactly what I'd hoped for, a good-quality coating that feels strong and looks just off glossy (4), that will hopefully keep the rust at bay for many, many years to come.

While the last coat was drying, I turned to the inside of the car, removing all the masking and going around the joins with more seam sealer (5). While that was drying, I checked out the scuttle panel. This is the box section underneath the windscreen, behind the dashboard, where the wiper mechanism and fresh air ducts live, a notorious weak-spot on Foxes. With the wipers, dash and heater ducts in place, either end of this box section is completely inaccessible and prone to rusting away out of sight and out of mind. If your carpets are wet in the front of your Fox, and the car doesn't have a sunroof, then rot in here is the most likely culprit. Even on this shell, the most rust-free Fox shell I've ever seen, that has been media-blasted and primed, there was still some rust hiding right up in the corners of this section (6), rust that I couldn't see before I stuck the camera in there! I went over the whole lot at either end with brush-on zinc-based primer while I was waiting (7).

restore floorpan

When the Eastwood Extreme was dry, I masked up the holes in the floor from underneath (8) and turned my attention to the inside. After a scuff with a sanding block and a good hoovering, I sprayed on a light coat of zinc-based primer (9) – and yes, the shell isn't dead level on its spit!

While that was drying, I amassed some tools (10) a trolley jack, foam pad, a plank, a floor lamp, a marker pen and an old screwdriver to act as a scribe. Using this bizarre array of guff, I got underneath the car and hoisted the first of the BMR Suspension subframe connectors into place (11).

restore floorpan frost autoThe Fox shell is a unibody, or monocoque (stop sniggering!), so there's no separate chassis. There are fairly stout box sections running back from the front bumper mounts, then down under the bulkhead to under the driver's feet, and very stout box sections from the rear bumper mounts to the forward mounts of the rear suspension lower arms. Between the two, there's nothing, the centre of the shell relying on the sills and the transmission tunnel for its rigidity. As most of it is pressed from thin sheet steel with a few spot welds and a rather laissez-faire attitude to manufacturing tolerances, this rigidity isn't all it might be. For anyone considering modifying a Fox-body, especially a convertible, good subframe connectors are a must. You can get bolt-on versions, but to do the job properly you should go for weld-on.

These BMR Suspension subframe connectors are weld-on, and among the strongest on the market. The instructions say that the car should ideally be on its wheels for fitting, meaning that a four-post ramp would be the way to go, but that's not an option for me at the moment. With the jack holding the connector in place I marked out where the welds would need to be, this vertical square tube (12) doing double duty by also bracing one of the rear suspension mounting points. There's a cross-bar section that bolts up underneath the mounting bolt holes for the front seats, so I bolted this into place (13) and marked where that would meet the fore-and-aft bar (14).

Now that the primer inside was dry, I decided to use a regular chassis black on the inside of the floorpan up to the waist, the bottom of the windows. The Eastwood paint had clearly spoiled me, as this was a horrible job. I had a big tin of brushable chassis black, a synthetic enamel, and it said “can be thinned for spraying”. It didn't say by what ratio, or with what thinners, so I guessed at 20% cellulose thinners. Bad guess. I began spraying and, within the first couple of minutes, my eyelashes were sticking together with the thick, airborne fog of chassis black. The finish was awful, like 120-grit sandpaper. I was heartbroken. This photo (15) isn't over-exposed or out of focus; that's just how thick the air was with this stuff. I tried the next coat with 50% thinners and that was loads better, and while it helped hide some of the sins of the first coat, it didn't totally cover them (16).

While that bloody lot was drying, I turned some attention to the rear axle. I will be building the axle into this casing (17), which was given to me some time ago by a fellow Fox fan and jolly nice chap – thanks, Bruce!

The Fox V8s use a Ford 8.8” C-clipaxle, and one of the main problems with these is that the wheel bearings have no inner race; they run directly on the halfshaft (18). Anyway, I wanted to strip the casing bare so I could send it off for blasting, so the first part to be removed is the pinion flange (19).

rear axle

That central nut is usually done up to an incredible torque, so I rigged up a tool to hold it – two three-foot lengths of angle iron, joined by a bolt at one end (20) and with a hole drilled in both other ends (21). This, bolted to the flange (22), would surely stop it turning? With a 27mm socket on a torque wrench (23), I braced the angle iron against the floor, the axle against the bench and myself against the torque wrench, gave a mighty heave…and went flying arse over tit, because the pinion bolt was done up to about 30ft.lbs. I could have saved a lot of effort by checking that first, really...

restore rear axle floorpan

A few paragraphs ago, I'd marked out where the subframe connectors would need to go and left it at that. That's because I wasn't going to trust my own welding for something so structurally important, and Tony, a friend of mine, said he'd be around in a few days to do it for me. There's no sense in leaving metal bare for longer than needs be, so when I knew he'd be coming around, I set to cleaning back to bare metal with a Clean'n'Strip disc (24). I also cleaned the edges of the subframe connectors that would need welding. This was a strange feeling for me – my car had a beautifully painted underside, and the BMR subframe connectors came beautifully powder-coated, and here was me scrubbing it off with a polycarb wheel...

mig welding frost autoThe reason I didn't trust my own welding here was that I was joining some very heavy-duty BMR tubing and bracketry to some rather thin, 30-odd-year-old Ford bodywork. In inexperienced hands, this is a recipe for blowing holes in the thin steel while the weld completely fails to penetrate the thick, so I hoisted the bars into place (which is ideally a two-man job), tacked them with a couple of tack-welds at either end (25) and waited for Tony.

Tony came along and, using my Clarke 160-amp MIG, made the job look easy (26). There was only one place where there was a bit of a gap, on one of the square uprights, but with a couple of tacked-together pieces of thin sheet steel hammered in the gap (27), they welded up a treat. The only problem was that the heat of the welding had burned some of my lovely Eastwood paint... Remember how I said that I'd kept a bit left over? Once Tony had gone, I brushed some zinc primer onto the fresh welds to keep the rust at bay (28). Here's a tip – if you're working underneath a car that's roughly three feet in the air, an old patio chair, rescued from a tip run, and with the legs sawn off (29), can really save your back!

While that was drying, and with the interior paint nicely dry, I went over the insides of the rear quarters and the A-pillars with some Schutz (30) for an added layer of protection. And talking of protection, I also had another new product to try – Eastwood's aerosol Internal Frame Coating – and even this transmission tunnel pressing looked delighted about it (31). It's a zinc-phosphate spray that uses a two-foot-long tube with a rose on the end, so you feed the tube into your box sections through bolt holes or gaps like this (32), then spray, and while you're spraying, drag the tube slowly back out of the hole (33). The rose ensures that the coating is sprayed all around the inside of the box section.

This is great, but one problem I discovered was that this thin coating will also find any excuse it can to get OUT of those box sections. Any unsealed joint or drilled hole will result in a little fountain, and this stuff, which is a horrible greeny-gold colour, dries almost instantly. Another prone area on a Fox is the front chassis rails inboard of the subframe mounts, so I was careful to dose this area well. This meant dosing everything around it, too (34).

eastwood internal frame coating

Fortunately, I hadn't painted this bit yet; there are plenty of bits of the inside and the underside that will have to be repainted. I also sprayed the join where the roof meets the windscreen surround, and down inside the A-pillars (35), where this stuff ran down and seeped into all the joints. Brilliant, that's exactly what I wanted it to do. It also dripped out a bit and ruined a perfectly good pair of boots, which I was less pleased about.

I've no doubt that it's a superb product, but I was expecting it to be a bit thicker – if you're coating the inside of a separate chassis, brilliant; if you're using it on a unibody or with the chassis insitu, some care and masking is in order. Why did I wait until now to do this? Because I didn't want to treat the inside of the box sections before fitting the subframe connectors, otherwise the welding would have just burned the coating off. Incidentally, for one good coat inside the major box sections and pillars on a Fox, I used almost two cans.

After all that, I thought it wise to turn my back on the whole thing for a day or two, so after going over the primed subframe connector welds with some Eastwood Extreme Chassis Black primer and an artist's brush (36), I made my excuses and left. More next month!

 

Related Products

- Frost Weld Thru Zinc Rich Primer Aerosol (500ml)

- Joggler / Joddler / Flanger Only (NO Hole Punch) or Joggler / Joddler Edge Setter / Flanger with Hole Punch

- Eastwood MIG 175 Welder with FREE Spool Gun

- Welding Clamps

- Sanding Blocks

- Scuff Pads

- Sand Papers

- Brush on Seam Sealer (1kg)

- Eastwood Extreme Chassis Primer

- Eastwood Extreme Chassis Paint US Quart

- Eastwood Internal Frame Coating (28)

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