Kubota M62 TLB Pin Retaining Bolt Snapping / Loose Nylon Lock Nuts

[JenniferKubotaM62]

Fellow Kubotan's.....

I made this video for a friend (named Darrell obviously) at the last minute and had no plans to put on YouTube so forgive the poor camera skills and narration. After giving it some thought, I feel others may benefit from it. It sure woke my eyes up to how quickly a very heavy part of your tractor can be laying on the ground looking up at you while you search the yellow pages for crane rental 2 hours from the closest SMALL town.

Jennifer

 

[lynnmor]

On many of these style bolts, Kubota instructions show 2 to 3mm clearance instead of tightening. There is a bit of clearance in the pin hole and a tightened bolt will take the load instead of the pin and bushing leading to broken bolts.

 

[GeoHorn]

deleted

 

[mcfarmall]

Typically, nylock nuts lose their locking ability when they are disassembled and reassembled. In critical applications it's best to install a new one. On the other hand, I have re-used nylocks many, many times on machine covers, guards, etc. and they still hold tight so go figure.

 

[JenniferKubotaM62]

deleted

Hey, why'd you delete it, I didn't even get a chance to read it.

 

[JenniferKubotaM62]

Well I checked out the snapped off bolt head (I still had it) and also checked another that I had pulled that had not snapped yet but I wanted to be safe (and compared it to the spot it was in). You can clearly see that grease does not get in that passage on the end of the pin, and they way it's designed, in motion it just scores and scores the bolt till it eventually snaps. The marking on the head is .7 which would imply with metric grade indicators that its around a grade 5 but with that scoring, and the remaining head piece I have left, it looks like it just scored the outside and then snapped, no twist markings on it etc.... you can see it wiped the threads right off and even bent it a bit, you all may want to check yours for score marks. They need to countersink/chamfer the rod shaped hole that goes across the pin as it's obviously stronger metal than the bolt and has spurs on their drilling.

Jen

 

[whitetiger]

You should go back and loosen all of the retaining bolts to get them back within spec. If you tighten them snugly, they will shear off. The nuts were left loose for a reason, so the pin and the bolt can shift around. The fact that you sheared a bolt is a tell-tale sign that you are not greasing often enough and/or are not using a good high percent Moly grease.
See the attached PDF from a Kubota assembly manual. The same applies to Loaders and Backhoes.

 

[JenniferKubotaM62]

You should go back and loosen all of the retaining bolts to get them back within spec. If you tighten them snugly, they will shear off. The nuts were left loose for a reason, so the pin and the bolt can shift around. The fact that you sheared a bolt is a tell-tale sign that you are not greasing often enough and/or are not using a good high percent Moly grease.
See the attached PDF from a Kubota assembly manual. The same applies to Loaders and Backhoes.

Thanks for your advice:

1: I did not tighen them all up, I realize why they are there, I just put them back where they belonged, that not being on the end of the bolt about to fall off.

2: If it hadn't snapped/I discovered it within 2 hours of it (the M62) being delivered, your comment about not greasing may be appropriate, but at this time it's an assumption, an incorrect one. The unit was purchased from the main Arizona Kubota dealer who had it in their rental inventory. The fact that bolt is so clean, implies to me that the grease passage does not go down that far so I could fill it with tube after tube and all it would do is come out the zerk (which is what it did when I greased it). I do have full faith they lubed it on a regular basis when it was in their rental inventory and I grease on an at least every 10 hours rotation. I may at some point pull them all out and put surface grease on for that reason.... As previously stated, I'm religious about grease, have a nice day.

PS: Thank you for the attachment.

 

[GeoHorn]

Hey, why'd you delete it, I didn't even get a chance to read it.

It was premature edification.

 

[JenniferKubotaM62]

It was premature edification.

Ok, well as long as you had a good time...

 

[Putneymountain]

I thought I'd ask the M62 owners...

Is it normal for a new Kubota TLB to have the loader bucket and backhoe bucket dump when the engine is shut off? There is a clicking sound, and the buckets drop over about half and hour. For the first hundred hours or so they stayed in place - and there was no clicking.

BTW - And I know that buckets shouldn't be left up - I just do it when I'm shoveling mulch or compost.

Thanks in advance for any help.