heat on bolts

[big hunter]

As I was splitting the 190XT yesterday I ran into 3 bolts that didn't budge. I used an oxygen/acetylene torch to throw some heat to them. I tried heating the metal around the bolts 2 times, didn't budge, then I heated the bolts, didn't work, then I heated the bolts, waited just a little while then poured water on them to try to cool them off fast...that worked. And I must say a torch takes paint off really quick, I'm wondering why I don't see people on here taking about removing paint with a torch. Also I'm wondering is there any such thing as too much heat on cast metal. I'm trying to get the back wheels off, been soaking them for a week (as best as possible). one guy on here awhile back said he heated his wheel hubs until they were red. Was wondering what you guys think.

 

[caterpillar guy]

Heating cast does not seem to have the same effect on it that it does on steel just have to be careful not to crack it be cooling to fast the heat usually won't crack it the cooling to fast will tractor wheel castings are ductile iron or malleable which reacts differently than cast to heat welding and to some extent cooling but still needs caution with cooling .

 

[MarkB_MI]

I use a torch on stuck bolts all the time. But there's no need to quench them; just heat the bolt head cherry red and put a wrench on it. The bolt will come out like it's screwed into warm butter. In fact, the bolt will get harder to turn as it cools off.

You might think that there's a risk of twisting off the hot bolt, but I've never had that happen. I did this trick on some lug bolts that were rusted about halfway through. I tried taking the first one out cold and it twisted off like it was made of clay. Then I got out the hot wrench and removed the rest intact.

Generally speaking, you should replace any bolt that you heat, since it will become annealed. But usually you're taking out a bolt that you would have destroyed anyway.

I've also used the trick on seized disk brake bleeders. There's no way to heat the caliper, since it's full of fluid, not to mention the seals. Heat up the bleeder to cherry red, grab it with Vise Grips and it will come right out. Watch out for scalding hot brake fluid, though.

Heating bolts works for aluminum as well as cast iron. I removed a broken screw out of an intake manifold using a small brazing tip and Vise Grips. I can't imagine any other way I could have extracted it.

 

[Anonymous-0]

I have stripped the paint from two tractors using a torch. It does work great. After it beads up just hit it with a wire wheel and it comes out shiny. I don't think you will hurt the cast by heating it, but I would be careful about throwing much cold water on it. That could crack or warp it.

 

[big hunter]

thanks for all the input

 

[Anonymous-0]

Cooling with water is not a good idea- possibility of breaking cast iron. After heating difficult bolts, try applying some candle wax as it cools. It melts between the threads and helps to ease the bolt out. I prefer heating the cast more than the bolt- can apply more heat, even up to the bolt being red hot.

 

[buickanddeere]

As you stated. Vital to replace the heated bolts. Important bolts under stress should be used once and tossed anyways.

 

[dave guest]

You can burn a hole in exhaust manifold with torch. Careful!!!!!!