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This isn't a 'is it proper' thread, and I will cull out anything that gets close to that topic.

But I do have a Harrison Heater and I have started to restore it (its finally warm enough to run the compressor in the garage).

Dissassembly was simple. Remove the clutch head machine screws (7) and the rear plate comes off. 4 more clutch head machine screws allow the core to be removed.

Here's the inside. Note the only rust is at the point where the core was held to the case. The left side 'nose cone' is typically the rusted out portion. I guess that's where moisture condenses the most? Not sure... but the left side is usually the part that is rusted out the most.



The back plate is unremarkable. The mounting studs will need to be replaced... no biggie. But relatively rust free.

After the back plate is off and the core is unscrewed you can just life the core out.

The small brackets that are silver soldered to the brass end tanks were rusted.. I heated the solder and they popped right off. I then wire brushed the copper tanks looking for cracks and verdige (that green stuff that forms when copper is wet for a long period of time.

Here are the copper tanks:




The mounting brackets must be sand blasted and will be soldered back in place after the core is pressure tested. I'm going to see if a radiator shop boil the core and repaint, but not pressure test. I'll do that myself so I can ensure they don't try to pressurize to 12psi and pop the damn thing.

Good and bad news.

Good news: The 6V motor works. Need to balance the fan blades, and the motor is a replacement (has a ground wire vs a single 6V power and case ground as per the originals). Not a big deal.

Bad new: Paint was hiding rust through at the nose portion (where, like I said, 90% of the rust occurs). Will be bondo-ing it.. no way I have the skill to make a patch and weld it in place. If I ever do get that good I can always blast the bondo off and weld it up proper.

Here's what was hiding under what appeared to be moderate rust where the core was screwed to the shell on the left side:




Not a huge issue.. but enough to make a patch more difficult than bondo.

My guess is that since this is a recirculating heater the moisture in the cab condenses at the nose and sits there. I'm gonna drill a small drain hole once it fixed to hopefully stop it from happening again.. and using an epoxy primer on the inside of the shell.