People laugh but i have a can of the prolong stuff for the most stubborn bolts. I use PB as the mainstay and only use that on stuff that is really bad. They used to sell it in the stores when they were promoting their corrosive snake oil for engines. Last i knew you pretty much have to order it direct from them online now.

My favorite has always been the GM heat riser solvent for rusted bolt and pins in corroded aluminium. That stuff just eats corrosion.
Gus

A spray bottle with plain ol' water! Water helped create the rust, therefore, water is the solvent that will loosen the rust. And yes, I live in Iowa so I know a thing or two about rust!

another vote for kroil, I order direct from kano labs

Ditto! That's all we used at work, worked great as long as they didn't mess with the formula.

Canadian Tire used to sell heat riser penetrant years ago. Can't get it now.

I use to have an 85 KW that had a seized piano type door hinge. I sprayed cans full of every brand you can imagine on it to no effect. One shot of the heat riser stuff and the red rust ran out of it. Another shot and a few more swings of the door and the door would swing shut and latch.

I'm thinking the active ingredient is acetone or toluene because the last time I could buy the stuff it was in a 4oz bottle so I poured it in a WD40 pump bottle and it ate the piston in the pump.

Kevin

Please explain.

Same here, started buying the GM stuff when my dodge dealer quite selling there's.

JB-80.. I have been using it for about 20 years. I tried all the rest that are listed above. JB- 80 works the best..

Do you use a drop of dish soap with it to get it to flow?

Hope everything's going well with your dad, very honest and easy to deal with back in the day. He and Kenny revitalized us Mopar guys with the Indy head low deck program(had one myself). Thank you

I absolutely love that stuff. It's all I use for rust penetrant. The part number did change to an AD. That's probably when the formula changed.

Jon here from HomemadeTools.net.

Thanks for the mention.

To celebrate our 20,000th homemade tool, we made a new ebook featuring our top 50 homemade tools. You guys are welcome to it for free:

http://download.homemadetools.net/50MustReadTools.pdf

Does Chrysler still sell the spray can stuff that they originally called
"Oxygen Sensor Thread Penetrant"
or something similar?

That worked wonders on stainless steel fasteners.

Conklin's Rust Bomb

Found this in Engine Builder online:

What’s the Best Penetrant?

A recent online article provided some information on various penetrating oils. A subjective test of all the popular penetrates with the control being the torque required to remove the nut from a “scientifically rusted” environment resulted in the following numbers.

Penetrating oils ……….Average torque load to loosen

No Oil used 516 pounds

WD-40 238 pounds

PB Blaster 214 pounds

Liquid Wrench 127 pounds

Kano Kroil 106 pounds

ATF*-Acetone mix 53 pounds

The ATF*-Acetone mix was a “home brew” mix of 50% – 50% by volume automatic transmission fluid and acetone. It has been said that lacquer thinner may be used as a substitute for acetone.

From: Engine Pro Technical Committee with special thanks to Machinist’s Workshop Magazine (www.machinistsworkshop.net) and Bert Hitzing.

R.

I tried the home brew, it wasn't as good as kroil.

I believe the 50/50 acetone/ATF works... that said, how many of us use heat if the fastener won't move with reasonable torque? Hitting acetone + ATF with a torch would be "interesting".

I think any penetrant "works" better if it's applied and subject to 1 or more heat cycles.
I learned about kroil when I worked in an auto shop where we installed a lot of tube headers. Spray some kroil on run vehicle for 10 minutes, spray a little more on let cool and remove the flange bolts and heat riser without ever breaking studs. Sometimes the stud would come out with the nut.
Is the mopar stuff called MP50? I've had good results with that, and pb too, but I don't like the smell of pb either.