MTD (Murray) 30" Rear Engine - Stubborn Blade Nut

[Mower King]

Got it this morning. Grass is growing like crazy with downpours lately so I had to do something. Had applied Kroil several days ago, wiped off the residue today and put the air-service 15/16 socket on the breaker bar. I had to raise the deck all the way (I run it only one notch down from the top) and still had to push it up to get that long socket on the nut. Solidly blocked the blade with a 2x4 in the discharge port, and put the heavy-duty jack handle upper half over the bar. Laying on the floor now, head to the front with a foot on the bar, and holding the front wheel to stop the mower, I laid some torque into it. I was sort of leery of breaking the tool and nothing was happening. Finally I said 'Break it' so I really gave it a maximum effort - POP! I thought I had cracked the socket but I had broken it loose! Went ahead and removed the blade and sharpened it. I don't normally use the bench grinder on a blade in good condition so I clamped it in the vise and used my favorite file - an 8" flat/round file from my Grandad's tools, probably 100 years old and still cuts the best I have seen. The rounded side is great for those curved cutting edges found on this and other blades.
Put it back on and used all the torque I could muster with just the breaker bar. I'm sure that will be good enough. I'd say I got about 95-100 lbs on it, comparing it to lug nuts with that same bar. I think it must have been on with at least 175.
Interestingly, the oil residue from the Kroil was on the flat flange of the nut as well as on the threads. That stuff really is 'The Oil That Creeps'. I don't know if I would have been able to break it loose without it.

I have not seen a blade nut or bolt that I couldn't get off ANY mower In my 17 yrs at the mow'in house with my Matco 1/2" air impact.....not because the Matco is crazy stout (which it is though) but, because all I did was disassemble cars & trucks for 25 yrs in an Auto Salvage.....I figured out how to get the toughest bolts out, there is a technic to the madness!

 

[bertsmobile1]

FWIW
The service van has 8' length of 2x4 hollow steel tube, a 3/4" 6' breaker bar and a scissor jack
When faced with an impossible bar nut/bolt the tube goes over the blade & breaker bar goes on the nut / bolt then the jack is applied till it is just lifting the deck to stop the breaker bar falling off
Even with this sort of leverage it is often a legs on the breaker to get the fastener to shift.
Now you have it off, make sure you slip the blade off regularly to prevent it overtightening.

 

[Hammermechanicman]

When i was a kid my father had a bunch of odd looking really stout wrenches with big square ends. They were striking wrenches. He used them as a mechanic working for the CCC during the depression. You hit them with a sledge hammer to loosen big bolts. Used them a couple times with a BFH.

 

[Scrubcadet10]

My uncle used to work in diesel mechanics and large equipment, (Cat Dump trucks, dozers ,draglines etc)
He said there were times on some stubborn nuts and bolts he had to use the end of a boom crane on a thick cheater bar, and use hydraulic power to turn the pipe and leverage with that pipe and long crane arm them... He told me how they set them up exactly but I can't remember..

 

[1saxman]

It won't be a big deal next time now that I know what to do. Part of my success was due to the breaker bar with long socket being just the right height so the weight of the deck held the socket vertical as I pushed the bar with my foot. This worked because I was doing it in the garage on the concrete floor.

 

[Mower King]

My uncle used to work in diesel mechanics and large equipment, (Cat Dump trucks, dozers ,draglines etc)
He said there were times on some stubborn nuts and bolts he had to use the end of a boom crane on a thick cheater bar, and use hydraulic power to turn the pipe and leverage with that pipe and long crane arm them... He told me how they set them up exactly but I can't remember..

Right, but we're talking about a simple mower blade nut...or bolt here!

 

[StarTech]

I used to use those breaker bars with extension pipes. I even had one that pickup the whole body of a large ATV off the ground trying to break free and axle nut. Now that I got a 1300 ft-lb Air Cat impact I longer need to hurt myself trying to free nuts with thread deforming locks that are torqued to 300 fl-lbs. I have ran into anything that is intentionly torque over 300 fl-lbs yet. So far I only snapped a few extensions and not busted any sockets.

 

[Hammermechanicman]

I used to use those breaker bars with extension pipes. I even had one that pickup the whole body of a large ATV off the ground trying to break free and axle nut. Now that I got a 1300 ft-lb Air Cat impact I longer need to hurt myself trying to free nuts with thread deforming locks that are torqued to 300 fl-lbs. I have ran into anything that is intentionly torque over 300 fl-lbs yet. So far I only snapped a few extensions and not busted any sockets.

Air tools are your friend.
We need a show us your air tools thread.

 

[bertsmobile1]

I used to deliver stuff to a local railway workshop.
One day all of the 24V ( long time ago ) impacts that I had been delivering were in a skip bin with reo welded over the top to prevent pilfering .
I asked the warehouse manager about it and apparently they had to go back to air as several railway linesmen had broken their wrists using these guns ( 1" drive ) and fu=inally, one had tossed an electrician off the top of the workshop carrige across 3 tracks and over the bridge wall so OH&S banned the battery tools and made them go back to air

 

[PTmowerMech]

A couple of days ago, this guy needed someone to take off one nut/bolt from a 5th wheel hook up he was selling. I went all the way up to the 3/4" air impact and it still wouldn't budge. So I cut it off with the cutting wheel. After soaking it in something all night, the next day, I had the bolt on the vice with a breakover and it still wouldn't budge.