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!

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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.

No cooling of the is necessary. the nut has expanded and broken free of the rust bonding it to the bolt.

As soon as it's glowing, or close (many times you don't need to get it glowing, though heat exchangers I always do), take it off.

it just evaporates at those temperatures. You could use a regular mapp torch and that can work shooting some PB Blaster in there after heating up

Good question. If you've never done it before, clean with a shot of brake cleaner and let dry, then apply the heat.


Something else to consider in general. Penetrants and heat don't give you license to just gorilla a stuck nut off. Part of the fun, for me, is working a nut off and getting a feel for when the bolt/stud is going to break. If you can get a tough nut to back off a little, hit it with some penetrant and turn it back ON. Work it back and forth. It's a great feeling when it finally comes off after a few minutes.

Yes it is! Last year I was working on the car and when I went to disconnect the left axle from the hub I found that one of the flange bolts had sheared off deep inside the hub. Uwanna was over at the house at the time. I didn't have a set of EZ outs small enough so he went back to his house to get a set. While he was gone I drilled a pilot hole and shot it with Kroil and let it soak in a while. When he got back the EZ out worked like a champ.

I've learned the hard way that sometimes patience is the best tool in the toolbox. It was fortunate that I had to wait on Uwanna to get back with the EZ outs. Otherwise I probably would've rushed it and made a bad situation worse.

Actually you have, it's already been mentioned in this thread -- Wurst Rost Off. It uses extreme cold instead of extreme heat to perform the same function, which is to break the rust bond between the bolt and nut due to differential expansion (in the case of heat) or contraction (in the case of cold).

Among commercially available penetrating oils, Kroil seems to be the best (aside from a homemade brew of ATF and acetone), but no penetrating oil is going to get inside a rust bond without breaking that bond first, using either heat or cold, or some mechanical means such as a sharp impact from a hammer.

Locktite Freeze and Release I bet is the same type of product. Have not tried either.

Used CRC freeze off (and the smoke wrench) on my oil lines and the nuts spun right off.

For real problematic frozen studs or nuts you'd be amazed how fast they come off if you simply MIG weld onto them. This applies a ton of heat very quickly but I suspect the electrical current flowing through the threads also has some effect. I've used this method to remove broken studs and also remove bolts that won't come loose. For bolts I just weld directly onto the outer part of the bolt, you can no longer use a wrench on the bolt but grab them with vise-grips and they usually come out easily.

Wow. Can you explain the process briefly? It took me days to loosen up the lines with spray Kroil and a mild application of propane.

Apply a liberal amount of CRC Freeze Off. It works the opposite of heat, helping to break the seal by chilling the nut. Wait a bit for the penetrant to work its way up the threads, then hit it with a MAPP torch to get the nut nice and hot. The contraction and expansion seems to work for me, but YMMV.

I was popping the pistons from the calipers ofmy Lotus Europa that had sat for over 20 years yesterday. One piston would not move when I hit the air. So I laid the caliper on its side and then soaked the offending piston with PB Blaster. Two hours later, I blasted the air, and it popped right out.

Not saying this will happen all the time, but it never hurts to try.

Thank you.

Same with me on a 60's Datsun 2000 Roadster. Waited a day though. Boom, right into a bucket. Was able to save them with only new seals.