Cracked KB2485 Sub-frame AGAIN!

[invictive]

Hi guys,

I have a CK30 tractor with a KB2485 Backhoe. I've had the backhoe for about 2 years now, and the tractor for 3.

Last fall I cracked the subframe on the bh where the 2 pieces join (2x4x1/4 welded to top of another 2x4x1/4) looking at the crack it seemed quite rusty so I thought it had probably been there for a while (bad weld?). Kioti of course refused to do anything about it since it was just out of the 1 year warranty period. I had my dealer weld 1/4" steel plates to either side and that seemed to do the trick.

Now a few months later the subframe has cracked again, this time where the diagonal bracing bolts on. It has cracked all the way through the middle of the bolt and the triangular hole to access the bolt.


This time I think I am going to have to replace the whole frame and I doubt Kioti is going to help me out.

I was just wondering if anyone else had run into this issue? The mechanic at my dealer said he thought he had heard of this happening to a few people. It seems like a design flaw to me. Not only are there 2 separate pieces welded together (why not just take the 2x4 all the way through?) but why would you cut away one side of the 2x4 to allow access to a bolt? For a machine that is so beefy it seems silly to then fill it full of holes.

Any ideas/thoughts/comments?

Thanks!

 

[beenthere]

Time to weld it up so it has the strength it needs, and overcome the poor design.

 

[MichiganIron]

The KIOTI Equipment lists do not show the KB2485 Backhoe on the CK30 subframe. We know they fit...but they are not listed as compatible by KIOTI Tractor. You may have had a warranty issue even during the original warranty period.

 

[mj007]

Hi guys,

I have a CK30 tractor with a KB2485 Backhoe. I've had the backhoe for about 2 years now, and the tractor for 3.

Last fall I cracked the subframe on the bh where the 2 pieces join (2x4x1/4 welded to top of another 2x4x1/4) looking at the crack it seemed quite rusty so I thought it had probably been there for a while (bad weld?). Kioti of course refused to do anything about it since it was just out of the 1 year warranty period. I had my dealer weld 1/4" steel plates to either side and that seemed to do the trick.

Now a few months later the subframe has cracked again, this time where the diagonal bracing bolts on. It has cracked all the way through the middle of the bolt and the triangular hole to access the bolt.


This time I think I am going to have to replace the whole frame and I doubt Kioti is going to help me out.

I was just wondering if anyone else had run into this issue? The mechanic at my dealer said he thought he had heard of this happening to a few people. It seems like a design flaw to me. Not only are there 2 separate pieces welded together (why not just take the 2x4 all the way through?) but why would you cut away one side of the 2x4 to allow access to a bolt? For a machine that is so beefy it seems silly to then fill it full of holes.

Any ideas/thoughts/comments?

Thanks!

I saw this on a tractor/hoe at the dealers' awhile back - my solution would be to weld the cracks back up from both sides and grind smooth then cut a sleeve of heavy wall tubing with ID large enough for the bolt to pass through and long enough to reach from the back-inside of the mount tubing to 3/8" or so (depends on the thickness of the access-hole patch plate*; see below) beyond the surface of the tubing at the access point- place the sleeve over the hole on the inside of the mount and center and clamp with a longer bolt then weld all around it to the backside of the mount tubing. Cut a plate* that will cover the access hole and drill a hole large enough for the tubing to pass though - clamp the plate* to the mount tubing and weld to the tubing and the sleeve - use a longer bolt to pass through the brace and mount tubing.

 

[Sly_Kioti]

I have the same problem with my backhoe

 

[dfkrug]

I have the same problem with my backhoe

Thx for posting those pix, SLY.

Your evidence supports my considered opinion that the factory Kioti
subframes (the low-mounted ladder style) flex too much unless a toplink
is used. Kioti provides the toplink hole, but some at Kioti say you don't
need it. Some at Kioti say to use it, however.

Flex leads to metal fatigue, like you have.

 

[Gittyup]

By the looks of the gussets, the weak spot is exactly where you'd think. Might be preventable if the horizontal/vertical gussets overlapped instead of ending where it's breaking.

 

[Kyle241]

Ouch! That was one of my concerns with Kioti's BH design. Like others, I suggest a good welder and beef it up.

 

[mguitas]

Ouch! That was one of my concerns with Kioti's BH design. Like others, I suggest a good welder and beef it up.

I would like to see koiti make the sub frame design like club cadet yanmar or deere, the sub frame runs along the side, an bolted on. Also puts the backhoe closer to the tractor.:thumbsup:

 

[cdaigle430]

You will definatly have to brace and beef this up-also, look for other potential week spots because once you beef this up, the next weekest link will most likely crack as well.

 

[dfkrug]

I would like to see koiti make the sub frame design like club cadet yanmar or deere, the sub frame runs along the side, an bolted on. Also puts the backhoe closer to the tractor.:thumbsup:

Kioti did a better job on the subframe for the LK30 TLB IMO. I really
like the newer Kubota and Woods subframes; Deere, not so much.

 

[kiotiken]

Kioti did a better job on the subframe for the LK30 TLB IMO. I really
like the newer Kubota and Woods subframes; Deere, not so much.

My Woods BH-70X is a monster, and it's got a subframe and mount to match. Initially, I was buying the tractor with the Kioti BH, but called my dealer back and asked him to add a thumb. He told me that Kioti didn't have a thumb for their backhoe but he could do a Woods BH for an extra $1K with the factory thumb. He also added that in his opinion, the Woods BH was a much better BH because of the subframe mount and that's the only one he'd put on his tractor.

Man am I glad I listened. I never actually saw the Kioti BH installed on a tractor (I had never used one and had already test driven the tractor and didn't figure I knew enough to go back and look at it anyway), but now having seen pictures of the mount I can say it looks very flimsy to me. I would agree with other people, take it to a very good machine shop and have them engineer a new mount that incorporates your existing mount, make it 10X as strong. I know that my BH-70x can pick up the back of my tractor and can pull the tractor around a bit, and that's with loaded tires. There's no way the mount in these pictures is going to take that kind of stress day in and day out.

 

[MotorSeven]

I would not replace the whole thing, as a good welder can beef up and fix your existing one for a fraction of the cost of making a new one.

 

[kiotiken]

I would not replace the whole thing, as a good welder can beef up and fix your existing one for a fraction of the cost of making a new one.

No, neither would I, sorry if I wasn't clear. I would use the existing and simply have an expert reinforce it in a way that will make it much stronger than it ever was.

I'm currently digging 400ft of trench to install some weeping tile to drain off an area that is soggy in the spring. I watched the interaction between the tractor and the backhoe last night and was surprised to see how much flexing was going on. There's so much force put through the mounting bracket, it needs to be extremely strong but allow a little flex. I love welding projects, but this one I'd defer to the pros.

 

[MotorSeven]

KK, you were clear, the OP was considering a replacement. I weld too, but your right, this one I would farm out to an expert.

 

[BSVLY]

The KIOTI Equipment lists do not show the KB2485 Backhoe on the CK30 subframe. We know they fit...but they are not listed as compatible by KIOTI Tractor. You may have had a warranty issue even during the original warranty period.

So why did the OP buy a larger BH than was recommended by Kioti? Seems they rate them appropriately based on applied loads-I would assume. So the CK-30 is rated for the KB2475; which might not have broken the subframe? Anyone with a CK30 and KB2475 have cracked subframe members?

I just put a KB2475 on my CK30...that is why I ask. Need to baby it?

 

[mguitas]

So why did the OP buy a larger BH than was recommended by Kioti? Seems they rate them appropriately based on applied loads-I would assume. So the CK-30 is rated for the KB2475; which might not have broken the subframe? Anyone with a CK30 and KB2475 have cracked subframe members?

I just put a KB2475 on my CK30...that is why I ask. Need to baby it?

There is one on the youtube, ck30 under barretts equipment. Its a old video, but it has the correct backhoe on. an i think the sub frame was crack in four places. the video was 8 minutes an 15 seconds long.

 

[Zork]

I would weld it up and drill two weep holes in the base of the tubing. The first photo shoes what appears to me as a ballooned tubing rather than typical 2X4 tubing. My thought is that maybe water got inside and either froze or expanded and blew the welds out.

 

[mj007]

So, did you have the 3-point top link attached to the BH?

 

[steve0413]

So just how dangerous can this be with the sub-frame breaking like that? I've heard horror stories about the 3pt BH breaking and crushing the operators.