I have recently decided to fix the heater switches and cables in my 55 fairlane. The levers were stuck and starting to bend. When I removed the heater levers I found a stuck temp cable and the heater control valve seized. I ordered the cable. Found a couple valves on e-bay. They were between $179 to $299. I decided to try and resurrect mine. It's a firewall mounted unit. It was in rough shape. I needed something to dissolve the rust. I was originally thinking naval jelly. Looked up some stuff online; didn't come up with much.
I was at the hardware store and one of the owners suggested I use this product by WD-40. You soak the parts in it and it dissolves the rust. The guy who buys it from him a lot, rebuilds antique clocks. So I figured I was good! Here are some before and after pics of how it came out.



There was an umbrella type seal on the valve rod. Preventing coolant from leaking through the valve itself. I used a grommet and a small rubber washer to replace the broken original seal.

I can post a pic of the magic WD-40 juice tomorrow.

Interesting. Please do post up the information on the "juice".

-Dave

 
Here it is! This stuff was really surprising. It's non toxic, biodegradable. It smells like nothing. No fumes in the shop. Didn't hurt my hand when I was digging parts out of the tub. It's a mystery. But it worked really well. Thanks Ace hardware!

How much was the container?

Looks like around $28 at WalMart.  Here’s a link.
https://www.walmart.com/ip/WD-40-300042-Specialist-Rust-Soak-1-Gallon/21969741

Lorena, Texas (South of Waco)

Also goes by the name Evaporust & others
Great product

I bought a gallon at Lowes for $25.00 and also got a $10.00 rebate from WD 40.  Carl