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NWH
New member
Username: oldyankeebarn1390
Post Number: 1
Registered: 07-2007
| | Posted on Tuesday, July 17, 2007 - 10:24 pm: | 
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I am restoring/rebuilding a "Ball Improved Reversing Gear Transmission". The bolts/screws are very rusted/frozen. I am trying PB Blaster and marvel mystery oil. What other magic fluids are out there that really work/
Thanks for your help. |
Robert
Senior Member
Username: robert
Post Number: 171
Registered: 07-2003
| | Posted on Wednesday, July 18, 2007 - 03:14 am: |
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Liquid Wrench
Vinegar (if no grease or oil present)
Propane torch - acetylene if you're careful. |
Peter Ogborne
Senior Member
Username: peterogborne
Post Number: 205
Registered: 09-2002
| | Posted on Wednesday, July 18, 2007 - 06:52 pm: |
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Heat and as Robert says be careful.If the bolts are rusted in try heating them but wait until they are cool before putting a wrench on them. The theory...the heat will break down the rust and if you can get a lubricant into the thread when they are cold you can well and truly loosen the rust....even water works well . |
Robert
Senior Member
Username: robert
Post Number: 173
Registered: 07-2003
| | Posted on Wednesday, July 18, 2007 - 07:20 pm: |
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Water, that's interesting! It seems to defy common sense in a way, but the other day I was working on freeing something off with heat and it wouldn't come even brought to a bright red heat, at least not after it cooled. I was advised to try it while hot, and indeed it worked. We could debate whether heating the surrounding object expands the threaded hole, or whether it contracts it. The same with cooling. Be careful of too much water as you can embrittle the bolt/stud or crack the surrounding metal through thermal shock. Let the parts cool down at their own speed. I've been told that part of the theory is the expansion 'crushes' any dirt or oxides etc. that may be binding the thread, as well as breaking through expansion and contraction, the bond between the two objects. If you want to get the bolt/stud red hot, you'll need acetylene. The higher heat allows faster heating of the part you want to heat, without as much heat migration to the surrounding material, which can be risky with cast or heat treated parts. Have to be careful not to actually melt your steel bolt/stud with acetylene though.
Better to try a lower heat and lubricants before going to a red heat, as you will remove any temper from the steel and may make them too soft for what they have to do. As Peter said, I would not try to turn a bolt or stud when red hot as it may just twist off. A nut I might chance, but not a bolt.
Phew, did I go on there or what? |
Peter Ogborne
Senior Member
Username: peterogborne
Post Number: 207
Registered: 09-2002
| | Posted on Thursday, July 19, 2007 - 06:50 pm: |
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I was told about using water to help free up rusted bolts by an old farmer.His method was to throw the object on a fire ,let it cool overnight and then soak it in water.I have tried it and it certainly works . Now of course you would have to modify the use of heat on critical items . The use of oil etc only results in a paste and sometimes inhibits the loosening of the rust. Where as the water dissolves the rust. |
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