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Friday, October 21, 2016

Triumph Spitfire Chassis Restoration #9

With the completion of frame repairs, I got back to prepping the frame for POR-15 and messing around with the differential (still). I got a wonderful stash of parts from Rimmer's on Tuesday (a day earlier than expected). Like I had mentioned, the big part was the stainless steel exhaust system, including the transition sleeve from the manifold to the exhaust. The manifold itself needs some serious attention. Hopefully I won't find any surprises there.

From transition sleeve (bottom) to the tailpipe (top). Orientation is wrong here, just fit them together to see it.

Close-up of the transition sleeve.

I also picked up the back part of the differential case from the machine shop (next day turn-around) with the new tapped hole and drain plug (also from Rimmer's) installed. Unlike a "standard" drain plug, this is more of a flush-fit, so it screwed in most of the way before the taper tightened it up.

Not very exciting, but here's the tapped hole. Just a bit off-center. I'll allow it.

Plug installed. I've got another rotation or two of screwing in here before it tightens up.

The job cost $25, which I thought this was a bit pricey. However, given that I didn't want to take the chance of messing it up and that I didn't have a drill bit or tap that big, I figure I saved money in the end.

I also got two new axle shaft bearings and the six studs for the leaf spring hold down plate. By the way, the holes for these studs go straight through differential case. In other words, they are convenient alternate drain points if you ever have the differential out and want to drain the oil rapidly.

The new studs for the leaf spring hold down plate.

I also got my butt kicked by the rear mounting bushings. I put them in the freezer for a while to get them to shrink up, applied anti-seize (definitely not required) and started them in. I tried to use the bench vise as I don't have a shop press large enough to take the size of the differential. Well, I only got them in so far before I just didn't have the oomph to squeeze them in any more. Asking on my favorite forum, they recommended using lubrication (hopefully the anti-seize would do that) and a combination nut/threaded rod and washers/spacers to squeeze the thing in place. Man, I just don't know. I don't think I'll get more leverage on that setup than I would be able to get on the vise, but the forum has never let me down before so I'm going to try. Otherwise, I'll be cutting them both out and trying again. Of course, the difficulty I'm having now at least partially explains why the old ones were so hard to get out in the first place!

The one I got most of the way in. The other was not as much.

In and around all of that stuff, I took to degreasing the frame. I first started with a combination wire brush, wire wheel and Gumout degreaser and several 3M Scotch-Bright pads, the green ones. Needless to say, I literally shredded these between the grease/grime and weld slag (mostly left by the factory, I might add!). Got a lot of the gross stuff out of there, though.

Before and after. Poor thing.

The Gumout worked great for the rough stuff, but since it's not water based, it leaves a somewhat greasy film that needed to get cleaned off. So, after using the Gumout, I started using the POR-15 Cleaner/Degreaser. This is a water-based cleaner, which is nice, and has very little smell to it, which is also nice. It is supposed to be combined with water at least 1:1. The instructions say 5:1 (water to cleaner) for "normal" jobs. Given that I had already done a lot of gross cleaning, I went with 3:1. Spray it on, keeping it wet, and let it sit for 10-15 minutes. I then went back with the Scotch-Brite pad and got everything nice and clean.

There were some painful spots, of course. Specifically, the area in front where the steering rack bolts in and the suspension towers attach. For the rear, the area around the differential front mounts and emergency brake cable guides was bad. The worse, however, was the differential rear mount. There is a lot of strengthening metal and nooks back there. I'm sure I won't get it all out in there, but I'll do my best.

Close-up of the repair area.

Same general area, other side.

Some spots I missed here, but I went back and got them. This area was particularly painful...

but not as bad as in there. I need to revisit this spot again just to make sure the next trip.

The final product...hopefully.

After the cleaner is done, you rinse it all with water. This made a mess, but it had to be done. I found some spots that I missed, of course, even on easily accessible flat areas of the frame. One of the nice things about using water to rinse is that you can see the spots you missed because the oil film causes the water to bead up. So, as I rinsed and found those spots, I hit it with cleaner, waited a few minutes, then Scotch-Brited it.

Next time I get over there I will take another looks at the trouble spots that I mentioned above. I'm sure I'll find some spots that need attention. After that's all sorted, it's on to the POR-15 Metal Prep step. This etches the metal to provide a good adhesion surface for the POR-15 itself. The process seems to be the same except it goes on full strength.

Until next time...


  1. Once the frame is painted and you can sit and look at it and plan "next steps" for putting on restored and new parts, I think it will give you a big shot of energy. your time, money, and labor is paying off! can't wait to see pics of the next phase.

    1. Thanks, John. I got over there yesterday for a bit and did the metal prep. So, paint is next!