L48 BT1100 Backhoe Fixing bushing play

[jovol]

Is repairing the bushings on a backhoe like this doable for someone without a mill/lathe? I do have a cutting torch (not that good with it yet) and a welder.

The bushings for both swing cylinders, as well as a couple bushings near the bucket are pretty wallered (oval shaped). I'm curious how shops normally fix this. Do they find the closest round bushing that will fit, and weld up the gaps? Or do they bore it out to the smallest round hole, then but a bushing in?

I'm also curious why Kubota decided to have the bushings be the wear items instead of the pins. Almost all but one pin shows very little wear, but the bushings are shot. Why wouldn't they use harder bushings and softer pins since pins are vastly easier to change?

Thanks for your help,
John

 

[SidecarFlip]

Consumer stuff like Kubota backhoes all use steel on steel bushings. Only the commercial units use bronze replaceable bushings (I just did a set on a Case extenda hoe). However, it was much less expensive to buy the 660CA bronze stock and machine them myself. Which I did.

Without any machine tools to line bore the sloppy bushings and sleeve them, you are SOL. Not a do at home backyard thing....and..

The entire unit has to be taken apart to access and fixture all the oval bushings to line bore them anyway.

Planned obsolescence and why it's so important to grease them often (Don't Kubota recommend every 10 running hours?). The reason for that is to maintain a boundary layer of EP grease between the steel bushings and the steel pins, negating steel on steel wear.

That also applies to your FEL, so keep it greased or suffer the same fate eventually.

 

[rentthis]

Are the pins worn through the bushings into the pin boss? If not, you only need to drive the old bushings out and drive new ones in. If the pins are worn past the bushings, that's where the problem starts.

 

[SidecarFlip]

Are the pins worn through the bushings into the pin boss? If not, you only need to drive the old bushings out and drive new ones in. If the pins are worn past the bushings, that's where the problem starts.

News to me. Never seen any Kubota accessory with pressed in bosses. Everyone I've ever seen are welded in. You care to enlighten me?

There are no sleeves in them that I know of.

 

[Lil Foot]

News to me. Never seen any Kubota accessory with pressed in bosses. Everyone I've ever seen are welded in. You care to enlighten me?

There are no sleeves in them that I know of.

Agreed. All welded, or no bushings at all.

 

[jovol]

That's a bummer, seems like a relatively easy thing to do at the factory to set everything up right with hardened bushings and softer pins.

I'm the second owner (bought at 2900 hrs). I certainly understand that maintenance and things wearing out is an inevitability... just wish they made it possible to fix it without a machine shop.

When you use the term "line boring," what does that entail? Is that boring a hole through all the mating components simultaneously so things line up? If so, that sounds damn near impossible on those swing cylinders... or maybe not if the backhoe is detached from the tractor.

I'll start calling around to shops and see what they recommend regarding bringing the whole machine in to the shop, or taking things off and bringing just what needs fixing.

Cheers,
John

 

[rentthis]

News to me. Never seen any Kubota accessory with pressed in bosses. Everyone I've ever seen are welded in. You care to enlighten me?

There are no sleeves in them that I know of.

Didn't say the b

News to me. Never seen any Kubota accessory with pressed in bosses. Everyone I've ever seen are welded in. You care to enlighten me?

There are no sleeves in them that I know of.

Didn't say the bosses were pressed in. I said that the bushings, where they exist, are pressed in. If we are talking about a BT1000 backhoe, there is a basket full of pin bushings. Obviously, if the bosses are worn that's where the torch and welder comes in.

 

[SidecarFlip]

News to me too. Far as I know, Kubota never made any pin bushings. Have a link or pictures?

 

[SidecarFlip]

That's a bummer, seems like a relatively easy thing to do at the factory to set everything up right with hardened bushings and softer pins.

I'm the second owner (bought at 2900 hrs). I certainly understand that maintenance and things wearing out is an inevitability... just wish they made it possible to fix it without a machine shop.

When you use the term "line boring," what does that entail? Is that boring a hole through all the mating components simultaneously so things line up? If so, that sounds damn near impossible on those swing cylinders... or maybe not if the backhoe is detached from the tractor.

I'll start calling around to shops and see what they recommend regarding bringing the whole machine in to the shop, or taking things off and bringing just what needs fixing.

Cheers,
John

Line boring is jigging the individual components on a vertical mill table and indicating the part square with the spindle and using a boring bar or small fly cutter to clean up the existing bore (make it round again) and then welding in a bushing with the OD to fit the bored hole and the ID to accept a stock pin. Bigger non-consumer hoes use a steel boss fitted with a bronze bushing, the ID sized to the stock pin and the OD to fit the steel welded in bushing. Really should be called 'align boring' but line bore is what it's referred to.

In reality you could fit bronze bushings to the re-bored steel boss and never have to worry about an oval bushing again because the bronze will take all the wear.

Exactly what I did to one of my FEL's last winter. I completely disassembled the loader, jigged the fabricated parts individually on a vertical mill and bored all the oval steel bosses, oversize to a dimension that would accept a 660CA bronze bushing with the ID machined to the stock pin size, pressed in the bronze bushings and put it all back together again. Steel or bronze don't matter except steel on steel wears faster whereas steel on bronze takes all the wear. You still need to keep it greased no matter what.

Like I said, I did a case extenda hoe last year with OEM bronze bushings. Piece of cake because all the machining was already done. Like I said, I machined the bushings in the shop because the OEM wanted a stupid price for them.

You won't find bronze bushings on any consumer implement. All about cost and end use.

 

[jovol]

Sounds like I need a bridgeport

 

[jovol]

Line boring is jigging the individual components on a vertical mill table and indicating the part square with the spindle and using a boring bar or small fly cutter to clean up the existing bore (make it round again) and then welding in a bushing with the OD to fit the bored hole and the ID to accept a stock pin.

For example, "line boring" the hole on the end of a hydraulic cylinder rod would involve removing the rod, squaring the length of the rod to the mill's spindle, and boring the hole?
If the hole was way bigger than the pin stock, would you weld in steel boss and then press a bronze bushing into that?

 

[SidecarFlip]

Sounds like I need a bridgeport

Spending 15-20 grand on a machine tool and then an additional 15-20 grand on tooling and not having the knowledge to use it seems insane to me. Lot more to machining accurately than owning a mill. Has to do with knowledge and education. I presume you lack those requirements.

Get it done in a shop and pay the price or forget about it and be sloppy.

 

[SidecarFlip]

For example, "line boring" the hole on the end of a hydraulic cylinder rod would involve removing the rod, squaring the length of the rod to the mill's spindle, and boring the hole?
If the hole was way bigger than the pin stock, would you weld in steel boss and then press a bronze bushing into that?

You don't bore a cylinder on a mill you chuck it in a lathe and bore it.... Watching too many You Tube video's I take it?

No reason to machine a cross boss anyway. You either weld on a new one or thread on a new one and many are threaded and the ones that aren't, you cut the old one off and weld on a new one.

If the cylinder cross bosses are oval as well, you replace them, never machine them.

 

[PoTreeBoy]

I thought the bushings were replaceable, too. My L35 (BT900 hoe) could use swing bushings all around. Look at the parts list on Messick's.

 

[SidecarFlip]

The reason why Kubota and every other manufacturer of consumer grade tractors and implements do things the way they do is bottom line cost.

It's a huge financial jump from consumer grade stuff to professional grade stuff. and I know of no company that produces a professional grade vocational back hoe that attaches to an existing tractor, no matter what the brand is.

You go up to a vocational grade hoe, it will be married to a dedicated chassis like say a JCB and will cost you 10 times more than your add on consumer hoe and have real replaceable bushings (bronze).

If I were you and I was considering a back hoe job, I'd look around for a used Mini-Excavator and buy that, do what you need to do and resell it.... or rent one which is what I do. a couple hundred a day for a complete unit, full of fuel and ready to go is a lot cheaper than fiddling with some clapped out stuff.


...............and even a small Mini-Ex will out dig and out perform any add on 3 point back hoe, hands down.

add on backhoes are a popular option that cause me to scratch my head. I cannot see any benefit in having one other than taking up space in a corner most of the time.

 

[Lil Foot]

Here is an example of "fIeld" lione boring:

 

[Lil Foot]

Knew an old Toolmaker who spent probably two years rebuilding a worn out backhoe. (don't remember the brand)
Holes & pins were all wallowed out & worn, so he disassembled it, bored all the holes oversize and threaded them.
Then he did a production run of about 60 new bronze bushings, threaded on the outside, with a hex head.
(looked like a giant bronze hex head bolt with a hole down the middle)
Made all new pins from ground SS, and re-assembled it. Bushings were screwed in and anchored with a set screw that was tapped into the "head" of the bushing.
I doubt it ever wore out, but if it did, it was a simple matter to swap bushings, didn't even have to disassemble the joint.
Probably had 100K in it if you figured his time, especially with Toolmaker tolerances.
but it was his hobby.

 

[jovol]

You don't bore a cylinder on a mill you chuck it in a lathe and bore it.... Watching too many You Tube video's I take it?

No reason to machine a cross boss anyway. You either weld on a new one or thread on a new one and many are threaded and the ones that aren't, you cut the old one off and weld on a new one.

If the cylinder cross bosses are oval as well, you replace them, never machine them.

Good points, you're right that does sounds way easier.

 

[jovol]

Here is an example of "fIeld" lione boring:

That answers a lot of my questions on how those holes are bored in awkward situations! thank you

 

[SidecarFlip]

Knew an old Toolmaker who spent probably two years rebuilding a worn out backhoe. (don't remember the brand)
Holes & pins were all wallowed out & worn, so he disassembled it, bored all the holes oversize and threaded them.
Then he did a production run of about 60 new bronze bushings, threaded on the outside, with a hex head.
(looked like a giant bronze hex head bolt with a hole down the middle)
Made all new pins from ground SS, and re-assembled it. Bushings were screwed in and anchored with a set screw that was tapped into the "head" of the bushing.
I doubt it ever wore out, but if it did, it was a simple matter to swap bushings, didn't even have to disassemble the joint.
Probably had 100K in it if you figured his time, especially with Toolmaker tolerances.
but it was his hobby.

Keep in mind that in my 'real life' besides playing farmer, I own and operated a job shop and have for years and I'm a Journeyman Tool and Die maker (Standard Tool, Cleveland, Ohio). We do short run automotive related machining and custom fabricating, so I get to play with customers stuff like backhoes and excavators. Matter of fact, I'm getting delivery of a used JCB loader / backhoe this week sometime that needs all the bushings replaced. and 2 buckets hard plated. JCB is even more proud of their replacement parts than Kubota is so I suspect I'll be machining the bushings from 660 CA bronze.

My hobby is gardening and making Triumph motorcycle parts and sleeping...lol
When people don't really know what is entailed to get to a point (like rebushing a backhoe, they think it magically gets done. it don't.

Unlike your friend, I don't try to reinvent the wheel, I just change the tread.