I have my '74 2.0 down to basically a bare shell (suspension is still in place) and I'm trying to figure out how to deal with the surface rust in the center tunnel.

A. Drill out all the spotwelds in the profile that holds the seat height adjusters and the tunnel itself and do it properly. Downside is that the flanges of the parts will be a bit mangled and might be hard to put back in place + very time consumning.

B. Cut open sections (on the top of) of both the profile and the tunnel, to get access and do the best job possible.

C. Using existing holes to scrape off lose rust and use a flexible arm with a rotating wire brush to get as much as possible out and then use long paint brushes to coat the entire tunnel with rust stopper.

D. Other suggestions?

I will run both fuel and brake lines under the car in the future and there is no rot to speak of, only surface rust + 40 years of dust.....

If it is only surface rust, I'd go with plan C.

The others are way too much work.

Eastwood sells a paint product for inside painting of frame rails. I have used it and I think it works great.
http://www.eastwood.com/internal-frame-coa...ray-nozzle.html

Beat me to it.
I have used in my tunnel. I had verylittle surface rust which I was able to scrape and vacuum out then I applied the coating from front to rear. The hose works great. I used 2 cans to coat but 1 may have done it.

I agree! Gets everywhere. Runs out of every hole so tape off where you don't want it to end up!

Nice product. I suspect people here using that inside the longs also? If so, how's it holding up (assuming you have ever had a chance to look inside again)?

Of course, painting inside the longs without removing that "muffler" looking thingy which would require cutting and welding and which is probably rotted out, may or may not be a good idea.

youtube video


https://www.youtube.com/watch?v=cm7W7Db5vdw

Yes I used quite a few of those Eastwood Internal Frame paint/sealer/rust treatment cans ..... it worked very well ...

I've used the Eastwood internal spray in the support structure of the hood and rear deck lids. I just did the one for Sandy's car. I could see surface rust when I pried up the edge and looked between the lid and the reinforcement. I tapped on the structure and the stuff was flaking off. I used a putty knife, blow gun, Rustmort, them masked off all the edges to avoid seepage onto the lid and sprayed the Eastwood in all the openings and down all the channels. The product was thin enough to weep out through the folded flanges. As it dries it seems to expand slightly. The bond seems tight and uniform. I was very happy with the results. Once I was finished I used urethane seam sealer around all the edges of the inner structure then painted the lid. Very nice smooth finish.