Kubota RC48-G20 (G1800) Mower Deck Stuck and Broken Bolts

[BruceWard]

Hi,

Last year I purchased a G1800 mower. Unfortunately I hit a rock and broke one of the bolts that held one of the side blades on.

Yesterday I removed the deck in an attempt to replace the blades and had hoped I could drill out or otherwise remove the broken bolt. So far I have found that a half inch cordless impact and the combination of a long ratchet and a hammer have not budge the bolts from the two blades. I have drilled the broken bolt to 27/64" Unfortunately it has not budged either. I have left the deck upside down with PB blaster hopefully soaking in around the inaccessible bolts.

So now I am looking for advice on how to proceed. I would be most appreciative of any tips on how to free the stuck bolts and if there are any aftermarket sources for the 76505-34530 (Shaft Blade LH) part that I am trying to drill the broken bolt out of.

Also is important to use the $20 Kubota bolt to secure the blade or can I buy a bolt with the same thread from a hardware store?

I have attached a picture showing the broken bolt.

Thanks in advance for your advice.

I promise to clean up and lubricate the deck then replace the blades every year. These must have been on there for a very long time!

 

[joecdeere]

Take it to a good welder, let him see if he can weld a nut to the remains of the shaft, if he can, many times the heat from the weld will be enough to help break it free

 

[Stimw]

Most lawnmower blade bolts that I have removed were Left-handed threads.
Have you considered this?
If you buy a bolt that has the same code on top then you are OK. Is it metric and left-hand?

 

[BruceWard]

Most lawnmower blade bolts that I have removed were Left-handed threads.
Have you considered this?
If you buy a bolt that has the same code on top then you are OK. Is it metric and left-hand?

Good point, I will not be able to easily buy a reverse threaded bolt!

 

[BruceWard]

As an update the bolts are right handed. They appear to be M14 fine pitch.

I escalated from a 1/2" cordless impact, to spraying with penetrating oil for a week, to a 1/2" air impact to 5 minutes of a torch to 15 minutes of a torch to building a stand and leaving the torch on the bolt for 1.5 hours before the air impact was able to free them.

As for the broken off bolt I drilled a pilot hole then drilled out to 3/8". I assumed it to be left handed so I kept increasing the bit size 1/16th at a time hoping that it would spin out the bolt. After realizing the threads were right handed I purchased a large bolt extractor and proceeded to break three adjustable wrenches, a fixed wrench and a ratchet trying to free what was left of the bolt to salvage the threads. Then I drilled the hole out, tapped it at 9/16" and attached the blade with a 9/16" bolt and several washers including a lock washer.

 

[mrmikey]

......several washers including a lock washer

My two cents worth, one gr8 flatwasher, one gr8 bolt and some blue loctite are all you need.
Extra flats will be more prone to loosen as is a lockwasher ( i hate the **** things and refuse to use them) The only time a lockwasher works is if the bolt comes loose as it allows the edges of the washer to dig in, by then the damage is done. That is provided the washer didn't break when you were tightening it, just my two cents worth........Mike