No, not talking about the Record10Carbon type of frozen nuts.
I’m trying to change the blades on an 8 foot Bush Hog, and cannot get 3 of the 4 blade bolt nuts loose. I’ve tried soaking the nuts in Liquid Wrench, Freeze-Off, and a concoction of 50% automatic transmission fluid and acetone. Also tried a pipe extension on a breaker bar with three people pushing/pulling, and a 1/2 in. impact wrench.
My plan is to rent a 1 in. impact wrench and try it, and if that doesn’t work, use an oxyacetylene torch and heat the nuts, but I’m kind of leery of doing that. Any other ideas?
Also, I just ordered some stuff called “Kano Kroil” which is supposed to penetrate down to 1 millionth of an inch. Anybody ever hear of/try it?
Not portable within my limited means of getting a trailer capable of handling the weight and getting the equipment up onto the trailer. My other options would be to hook it up to the tractor an drive 8-10 miles to a garage, or call a mobile truck repair place (the kind who fix semi-tractor rigs) and have them make a service call to the farm.
Heat, cool, heat, cool, heat, cool. Try it while hot, try it while cold.
Impact wrench is a good idea if you have a very good head on the bolts. Otherwise you’ll just round the head. Impact wrench may just tear the head off as well.
There isn’t an “L” on the nuts/bolts anywhere is there? Not that I have ever had a bad experience missing that little factoid or anything.
As NCTri mentions, PB Blaster and heat should get most anything loose (assuming you are turning it the right way). I wouldn’t be all that afraid of heat unless there is some sort of rubber seal nearby.
At this point, heat is probably your only option. How long did you soak the nuts in the penetrating oils? I’ve had some luck leaving it overnight. I’ve had to heat up bolts that an impact couldn’t get off. It’s not too hard, heat it up, let it cool and then try an impact gun. You could also just cut the nut off. I don’t know what this looks like or it’s placement, but if you have enough room, you can cut most of the way through the nut and then pry it off with a chisel. I’ve never had to do this before.
If I rent the impact wrench, I will have to rent an appropriate-sized compressor to go with it. I tried a propane torch, but these are some big-ass nuts, so I don’t think I’m really heating them enough.
Sharpening the existing blades is not an option as they are really eroded.
No, no “L” on the nuts. The bolts do have a key on one side that fits into a keyway and keeps them from turning. I have to pound the bolts out from above after I get the nuts off. The nuts are standard (right-hand) thread.
I’ve always found Mapp Gas works out for me to get tough stuck on axle bolts for cars (17mm hex head for a German car). Gets it hot enough but not too hot to melt the steel.
Have you tried tightening the nuts? Seriously. Try tightening as well as loosening.
You’ve already tried acetone/ATF, so don’t bother with other penetrants. Waste of time.
If you try heat, you have to get things pretty hot. One of the ways in which heat works is by driving off the water of hydration from the rust in the threads (rust is Fe2O3.nH20, roughly). This substantially reduces the volume of the rust within the threads, which reduces the strength of the rust bond. The problem is that you have to get things really hot to accomplish this, at least to a red glow, and keep it there for a while. Note that this will draw the temper of the nuts and bolts, which will make them easer to round off and strip.
If you have clear access to the nuts, it might be easiest to cut them off, clean up the bolts, and replace the nuts. Tedious, but low risk.
Heat, cool, heat, cool, heat, cool. Try it while hot, try it while cold.
Impact wrench is a good idea if you have a very good head on the bolts. Otherwise you’ll just round the head. Impact wrench may just tear the head off as well.
Heat, cold is your best bet.
~Matt
This ^ Worse case cut nut away with a angle or die grinder being careful not to hit the threads if you still need them.
Access to the nuts is down through a 3 1/2 " hole in the deck. Access from belw is not an option due to the stump jumper plate being in the way. No feasible way to get to it or I’d probably have done it, as I have already bought new bolt kits.
Yeah, I saw a post about a study supposedly conducted by Popular Mechanics that showed the acetone/ATF mixture to be the best penetrating lubricant in terms of the amount of torque needed to loosen a nut. I have tried tightening, but no go as the nuts were supposed to be tightened to 450 ft. lbs. at the factory. Add to that 13 years of rust.
Soak them every day for a week with the kroil/PB then USE HEAT and a cheater bar or impact. Another old machinist trick is to melt paraffin wax into the threads after applying heat and then break them loose.
