Impact Wrench For Removing Diffs/Tcase Plugs Damage?

- 3.4 L V6
- Need to do diffs and TCase
- Bolts very seized
- Really good deal going on at my local Harbor Freight for their Hercules impact at the moment
- Thinking of buying and impacting the bolts off, replacing bolts and using hand tools to torque them back down to spec (don't want to crack the diffs/tcase)
- Question - Will the impact motion crack my diffs/tcase when taking them off? Not going to use the impact to put them back on for fear of cracking something but not sure if taking them off with the impact will avoid damage

 

Impact wrenches are great for disassembling old rusty and seized bolts. Use some penetrating lubricant beforehand. You can use an impact for reassembly if you know the gun and it's settings. ALWAYS start bolts and nuts by HAND FIRST.

 

Did you try heat, penetrating oil? Try smacking the bolts (lightly) with a hammer to break the seal. If you want a new toy I don't see what damage the impact will cause, in a proper use case. However, caution a lot of my cases under there are aluminum. Lefty loosey, righty tighty.

 

No I haven't tried the heat/oil yet the deal is so good I figured the time/cost ratio is so high I may as well buy the impact and save my self a ton of time wrenching on the bolts and I would have it for future tasks

 

So you are saying break the bolts free first by hand then impact them off? In that case I may as well not buy the impact

 

They key to using an impact properly lies in the socket, 12 point sockets will cause problems, cheap 6 point black oxide ones are no better and buying a set of 4 point for a one time use, thats up to you. If it is a recessed allen same thing applies, a cheap soft allen will screw you over very fast.

 

No, he's saying when it's time to reassemble always start the fastener/plug by hand to make sure it's threaded correctly. If the threads are not aligned and you put the juice to it with a impact tool it will become cross-thread and it's game over.
Also when removing a stuck fastener, try turning it in the opposite direction a couple times. In other word move in the tightening direction, then in the loosen direction. Back and forth.

 

No, feel free to break the bolts loose with an impact gun. When you reinstall things make sure you thread everything together before using the impact gun to tighten. Be aware of how tight the impact gun makes things on whatever settings.

E.g. I use my Kobalt brushless impact screwdriver to install my lug nuts. I get each bolt threaded onto the stud, then use my impact on setting 2 to seat everything. Afterwards I use my torque wrench. Bolts still spin 1/4 turn before the torque wrench clicks.

 

Professionals rarely use impact wrenches on drain plugs. We use air chisels to free them up though.

The front diff allen keys are the worst, I smash them with a hammer, then smash the key into the drain then try to remove with a standard ratchet.

 

Just a word of advice, don't get a compact size impact for this job. I just did the diffs on my FJ and I couldn't get the plugs off with a breaker bar or my regular 1/4" impact. I had to break out the 1/2" to get those off.

 

Bro if you want an impact gun just go get one. No need to have us validate your purchase. It will free up most rusted bolts. Where impacts don’t work, heat will.

 

Great tool to have available

 

Thanks for the input all. Going to grab the impact and see how it goes. Def not going to fasten them tightly with the gun will be using my trusty hands/rachets/torque wrench

 

For stuck drain plugs I like a long breaker bar after a bit of MAPP gas heat. MAPP is key, it really puts the heat in quickly so it stays local. Yellow, no blue. Never had one I couldn't get removed that way.

 

These days you can get a real banger of an electric impact wrench pretty cheap. Interesting to note that back in the 40's they had electric impact wrenches, but not battery powered. What is old is new again.

 

FYI, MAPP gas is no more
They stopped making it in 2008

The yellow bottles are now map-pro, which is barely hotter than propane

 

No shit? Dang, guess I got a stash of the good stuff. Ox Acetylene would probably be the best go to then.

 

I’ve got an HD Craftsman 1/2 inch electric impact I bought in the 70’s. Used it to remove H-D Big Twin compensating sprockets. I’ve got all 3 versions. Electric, Pneumatic, Cordless. I keep the electric in case the cordless doesn’t get the job done at a remote site with AC but no air.