Kubota LA724 Loader Bushing Repair Questions

[RedNeckGeek]

I have a Kubota LA724 front end loader and after nearly 2000 hours (only 600 of those are mine) it has developed about 0.060" of wear on the ID of the top rear loader arm pivots. I haven't disassembled the parts yet and don't know what's going on with the inner bore, but the two outer bores are both worn, and neither seems to be bushed. I'm wondering what the best approach would be for this repair, as the outer edges of the bucket flop a couple of inches vertically when I curl it, and that makes grading very difficult, not to mention trying to use the fork lift attachment.

My first thought is to use an adjustable hand reamer to increase the 1" bore to 1.125" and use oversize pins, but don't yet know what I'll find on the inner bore (bushing or not). The outer bushings are on a part that I could move to the mill for boring, so that's another option, but the two loader arms that host the inner bores are joined by a cross tube, making the assembly too heavy to move and position. If I get lucky and find a removable bushing on the inner part, I could either purchase or make a replacement to accommodate the larger pin.

Has anyone used a hand reamer to take out this much material? It seems like a lot of metal for something that would be done by hand. I also wonder how well the alignment would be held between the two outer bushing bores.

Any other ideas on how to proceed would be much appreciated!

 

[rswyan]

I have a Kubota LA724 front end loader and after nearly 2000 hours (only 600 of those are mine) it has developed about 0.060" of wear on the ID of the top rear loader arm pivots. I haven't disassembled the parts yet and don't know what's going on with the inner bore, but the two outer bores are both worn, and neither seems to be bushed. I'm wondering what the best approach would be for this repair, as the outer edges of the bucket flop a couple of inches vertically when I curl it, and that makes grading very difficult, not to mention trying to use the fork lift attachment.

Just going off memory, it seems to me that when discussion of bucket floppiness has come up before, internal seal leakage (blowby) within the hydraulic cylinders was mentioned as a possibility, or as having played a role.

That's not to discount slop in the pins/bushings as being a contributing factor as well.

I have a B2910 (LA402 loader) with 1600 hours on it which has considerable pin/bushing sloppiness ... so I can appreciate where you're coming from.

My first thought is to use an adjustable hand reamer to increase the 1" bore to 1.125" and use oversize pins, but don't yet know what I'll find on the inner bore (bushing or not). The outer bushings are on a part that I could move to the mill for boring, so that's another option, but the two loader arms that host the inner bores are joined by a cross tube, making the assembly too heavy to move and position. If I get lucky and find a removable bushing on the inner part, I could either purchase or make a replacement to accommodate the larger pin.

Has anyone used a hand reamer to take out this much material? It seems like a lot of metal for something that would be done by hand.

Well ... I just got done using an adjustable hand reamer to ream out and fit about a dozen or so pieces of 1" D.O.M. tube for pin mounts on a root rake/grapple I'm building ... and yeah, it does seem like a lot. I'd think a better strategy would be to drill the holes close - maybe with a mag drill for the parts you can't get into your mill - and then ream them with an adjustable hand reamer for the final fit.

I also wonder how well the alignment would be held between the two outer bushing bores.

Assuming that the two outer bushing bores that you refer to are part of the same piece, then a reamer that was long enough to ream both bores at once would seemingly handle that issue ... although I'm not sure what the likelihood is of finding such a tool.

I know McMaster-Carr has some long reamers - as well as bushing inserts - ... but in the length you'd need (7" +/- ?) I don't think that they are adjustable.

Hmmm ... looking a their site I see an extra long adjustable reamer with a range of 15/16" to 1 1/16" ... with a pilot, to maintain alignment ... have a look at item no. 3027A18 and see if that might work for what you have going on. (Warning - their stuff ain't cheap ... but compared to the cost of having it done, it might be, relatively speaking ...)

Any other ideas on how to proceed would be much appreciated!

I'd search the site (TBN) for "bucket floppiness" (or some such) and see what you come with ... just to be sure that what you think is the problem (pin/bushing slop) is the actual problem ... as opposing to just being a contributing factor ... perhaps not even the primary or major one.

 

[RedNeckGeek]

Still haven't tackled the worn out bushings, but Enco has a sale this week and I'm about to pull the trigger on a pair of adjustable hand reamers that look like they'll do the job. I think the bushings are the cause of the play:

That's a pocket knife with the blade stuck into the gap between the pin and bushing bore. Nominal diameter of the pin is 1.125"; I measured 1.271" across the largest ID of the bushing. That's 0.150" of material to take out with the hand reamer and it seems like a lot:shocked:. The part shown could be mounted on a mill table and bored close, then reamed, which is probably what I'll end up doing. With that part in hand, though, I could also cut off the bosses and weld new ones on, then drill and ream to original 1.125" size. Still haven't taken the assembly apart to measure the bore in the boom arm of the loader, and as I mentioned in my first post, the loader arms are joined and it would be a real trick to horse them onto the milling table.

Just thought I'd revive this thread and see if anyone has any other ideas for how to make this repair. It sure would be nice to take care of this in this New Year!

Thanks!

 

[varmint]

Could you drill out the bosses, to say 1.375", and then insert new bushings with the correct ID? I suppose fixing them so the grease passages stayed lined up might be tricky. And, I gotta wonder if a lack of grease caused some of this to begin with, or just hard use? The pin looks okay. Be interested in seeing how it turns out.

 

[Herkypilot]

And, I gotta wonder if a lack of grease caused some of this to begin with, or just hard use?

I was wondering the same thing -

 

[RedNeckGeek]

Could you drill out the bosses, to say 1.375", and then insert new bushings with the correct ID? I suppose fixing them so the grease passages stayed lined up might be tricky. And, I gotta wonder if a lack of grease caused some of this to begin with, or just hard use? The pin looks okay. Be interested in seeing how it turns out.

The more I think about it, the more I like the idea of using a bushing. Thanks for suggesting it, varmint. I don't think the grease fitting will be much of a problem. A couple tack welds on the end should hold them in place just fine, and if they ever have to come out again I'm better with a grinder than I am with a welder. I'm disappointed Kubota didn't use bushings to begin with, but stuff breaks on this tractor that never should and I don't abuse it.

The tractor came to me with about 1300 hours on it. Both rear anchors for the curl hydraulic cylinders on the loader were broken off, the cutting edge of the bucket was bowed down two inches in the center, the main chassis rails under the engine had been re-welded, I think one of the rear gear housings had been monkeyed with, heaven knows why, and the seal for the forward 4WD shaft was leaking at the front of the tranny (had to split the tractor to fix that one). Not surprising the worn out pivots hadn't been lubed, and when I got it neither of those zerks would even pass grease. Lack of lubrication was the least of the problems with the poor thing, but I never could say no to an abused machine that needed a good home.

 

[skyhook]

Its hard to see with "all that grease" still in the way!
But it looks like there is an inner bushing that could possibly be replaced along with a new pin.

 

[Winmac]

The quick and dirty repair(maybe not the preferred) is to cut the worn boss out of the loader frame and weld in new ones. A full length of round stock can be used to maintain alignment to the good side.

 

[The Fred]

Might be easier, cheaper to hire a line boring repair company to come out or bring them the loader they would simply overbore the whole thing and use an oversized pin.

By the time you fiddle and fool with the repair yourself and get it all lined up properly you might be ahead of the game to farm it out.

Good luck whatever you decide.

Regards, Fred

 

[RedNeckGeek]

Reamers are in hand and I've got a block of time over the next week where I hopefully won't need the tractor, so I'm going to dive in on the pivot repair. Thought I'd start by trying the adjustable hand reamer on the inner member to see how much work it'll be just to get it back to round. If I get that far I'll make a decision to use a bushing or to just turn a larger diameter pin. When it comes to the two outer bores, I think I'll try to ream one free hand, and if the alignment starts to wander, I'll make up a tapered busing to fit the od of the reamer shaft and the ID of the opposite bore. Might need to grind flats on the reamer shaft, but that should keep things reasonably aligned.

If none of that pans out, I can always cut out the old bosses and weld in new ones, using a pin to keep everything lined up. The only trick will be finding a way to bore out those inner bores, as they are part of a welded assembly comprised of both loader arms. Maybe I'll make a call to the local rental outfit to see if they have a mag drill available, just to be safe...