PB Blaster, Wurth Rust Off, etc. Do they work?
 

I got a couple of responses to my query about hooking up an exhaust gas analyzer to my SC suggesting it might be hard to get the plug out of the catalytic converter and that PB Blaster might be the answer. Lucky for me, the plug is shiny as a new dime and comes right out, BUT, it got me thinking about penetrating oils. I gave up on them years ago after taking apart countless parts I had "soaked" which were dry as a bone inside, once they finally gave way. I've had a lot more success with heat (oxy/acetylene or even propane) and impact tools.

Am I missing out on a new generation of penetrating oil products that actually work? I searched this forum and found a post that said a guy got all 12 of his exhaust studs off in half an hour using the Wurth product, the label of which said "sprays on at -40 degrees causing cold shrinkage in the joint which develops micro-fine cracks allowing the penetrating oil to get in" Wouldn't that be something?

So, should I give this stuff another try?

Kroil, often called Aero Kroil or Auto Kroil is the best IMHO.

Tom

50/50 ATF/acetone mix works better than most, but you're right about the usual lack of penetration. I use Maltby penetrant at the shop, which helps, sometimes.

PB Blaster is fine but I've had more success with Kroil. It seems to work faster to me.

I've also had a lot of success with the heat/cold shock trip. For a stuck bolt, heat the bolt and the area around the bolt and then press an ice cube on the bolt itself. The shock from temp change seems to help loosen things up a bit.

If you wanted to cold shock the bolt/nut, a can of 'air' that people use for dusting off computers and such works well, especially if you turn the can upside down and the liquid sprays out.

You mean cold shock the bolt once it's red hot?

I'm with john walker. Tranny fluid and acetone half and half. Don't mix a lot cause acetone evaps quickly. Put on after 5 mins whack it with hammer and reapply. (Whack breaks rust seal and allows fluid to get it. Work bolt both ways in micro turns. Reapply fluid as needed. It this doesn't work apply heat map gas is hot hot.

+1 Kroil

My take is that the secret is time(2 days) to soak in, I like Marvel Mystery Oil and put it on 4 or 5 times over a couple days. My rusted torsion bars took heat as well though.

Tough to get stuff cherry red without two tanks. If cherry red you usually don't need penetrant.

The shock from ice on bolt is eventually delivered where the bolt meets the internal threads. Heat, cold, tapping, trying to tighten a bit, etc is intended to jostle the corrosion between the two sets of threads. Once it starts to break down, then stuff like penetrant has a fighting chance to sneak in.

It's not a science without oxy/acet. It's a patience game. Little of this, little of that, walk away sort of thing. If you get frustrated and use big muscle the party ends quickly.

I'm going to give that acetone and ATF thing a try. Seems like oxy/acetylene (the flaming wrench) is the ultimate though, if judiciously applied, and I've gotten pretty comfortable with it. Can't always use heat though, so good to have some alternatives. MAP might be good intermediate step, or alternative if you live in an apartment and have trouble hiding your gas welding rig from your landlord.

+ 1 for Kroil or Aero Kroil. It is a bit expensive but it has worked on everything I have used it with.

I have tried the acetone/ATF mix, it works ok, but it's a smelly mess and the acetone evaporates quickly. My goto has been Kroil for years, have found nothing better!

Here's a special discount deal on 2 Kingsize cans direct from Kanolabs for $14.50 plus ship $5.95 more than you'll probably ever need!
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++1! Tried many but Kroil is amazing!

Kroil works best,PB blaster is good also. Oxy/Acetylene can't be beat for right now...

PB Blaster works 95% of the time for me. 4% I break out the mapp cylinder. 1%, oxy-mapp comes out.

Started with mapp and 150psi into the gun, though a lot of torque is lost with the u-joint (broke one) and extension, this bumper shock bolt would not budge. Oxy-mapp is so satisfying. Never broken an exhaust stud either.

http://forums.pelicanparts.com/uploa...1402940044.jpg

http://forums.pelicanparts.com/uploa...1402940056.jpg

http://forums.pelicanparts.com/uploa...1402940067.jpg

http://forums.pelicanparts.com/uploa...1402940078.jpg

http://forums.pelicanparts.com/uploa...1402940090.jpg

http://forums.pelicanparts.com/uploa...1402940101.jpg

Thanks for the pics, literally cherry red. Quick questions on your process:

1) do you quickly cool the bolt down somehow (heard others use air canisters)

2) if not, do how long do you wait before torquing the bolt?

3) is the idea to apply penetrating oil AFTER applying crazy heat?

4) considering I have already soaked my header studs in both Kroil and Wurst Rost Off should I thoroughly clean the area before applying a torch? Sounds stupid ... Just don't want to die a dumb fiery death under my 911sc!

Thanks!

What VintageCarLover said about braking the rust seal. I have often worked off an impossible nut by soaking, shocking with pin tool and hammer, and working the nut both loose and tight in slight turns, which breaks the seal, then reapply solvent of choice again and give it some time.

EDIT: If the Jesus Bar cannot loosen it consider a Dremel or similar nut cracking tech.

I never bother to rapid-cool it. Heat it in such a way as to maximize the temperature difference between the nut and bolt. The difference in expansion will break up the rust enough to allow penetrating oil to get in there. Soak it, be patient. Don't try to turn it while it is hot. Hot steel is soft and you run a risk of breaking it off, plus you've just burned off all the lubricant.

Yes. Heating will remove all lubricant and if you don't lubricate the threads they can gall and seize up.

Unless you've got oil all over everything, just heat it slowly at first. The lightweight penetrating oil will evaporate off.

All good advice especially using heat but I have heard of one the freezes the joint but I don't know the brand name.