CAT Loader Repair

[whtbaron]

Well, the loader bucket had a broken hook on one side from the previous owner, and I needed a guinea pig for the new-to -me Dialarc so this is where things went. I have never welded with DC before, so I started out with the Chinese 7018's that I didn't like at around 90 amps. No sticking, but they still need to be scratched on the concrete every time you start, so they were still annoying. I was just going to make a quick tack but that Miller just wanted to weld...



The hook had been broken before, so I needed strength. At this point I switched back to the Eutectic rods and ran them at the max recommended 95 amps. Ran like butter and much easier to control than when I was running them hot for the loader arms.


I needed to fill in some gaps between the shape of the hook and the base so I decided to try some bigger rod and got the 5/32 7014 out at 175 amps. Waaay too hot... it was like holding a bolt of lightning. Calmed things back to 145 and it worked good...

[whtbaron]

Finished hook isn't exactly the same shape as the other side, but it should work good if I don't abuse it too much.

Finished product after grinding and paint.

[farmersammm]

7018 in, the DC flavor, is notoriously hard to restart. Only way is to do as you're doing........scratch the tip to clean off the flux, and the molten blob. It's why I like AC 7018 for short multiple welds.

[whtbaron]

I bought that back when I just had the buzz boxes so it is AC rod. I have that brand in 7014 and 6013 too, and they seem alright. I won't buy it in 7018 again though.

[Lis2323]

I bought that back when I just had the buzz boxes so it is AC rod. I have that brand in 7014 and 6013 too, and they seem alright. I won't buy it in 7018 again though.

I've never tried AC 7018s.

Coincidentally I am the midpoint of getting rid of my AC buzz boxes so I see no need to run out to buy a pack.

I've sold two Forneys and one Miller.

Still have two Forneys and one Miller to go. LOL.


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[Welder Dave]

That bolt on hook is a poor design and I wouldn't trust one that was welded. I'd get a proper weld on hook and weld it directly to the bucket. Here's a simple hook. There are are other styles too.

https://www.northerntool.com/shop/to...8590_200658590

[Lis2323]

That bolt on hook is a poor design and I wouldn't trust one that was welded. I'd get a proper weld on hook and weld it directly to the bucket. Here's a simple hook. There are are other styles too.

https://www.northerntool.com/shop/to...8590_200658590

I use those hooks. Princess Auto has them!




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[SweetMK]

That bolt on hook is a poor design and I wouldn't trust one that was welded. I'd get a proper weld on hook and weld it directly to the bucket. Here's a simple hook. There are are other styles too.

https://www.northerntool.com/shop/to...8590_200658590

When I look at the unpainted one, I kinda think that is not a hook,,
it is more like a quick attach for some accessory, like a set of forks.

BUT,, the rusty hook might just be so "sprung open" that it appears like it is not a hook,,,

[Lis2323]

I would guess the previous owner welded a regular chain hook to the base of a broken TOW hook base.


Maybe it was originally like this, designed for a truck frame..




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[whtbaron]

From what I've seen, that's the way CAT made them... it might be a little bent. I'm not worried, any heavy lifting I would run the chain through the loops on the back of the bucket like it is in the pic. The hooks are just to keep the chain from sliding off the end of the bucket.

[12V71]

I would guess the previous owner welded a regular chain hook to the base of a broken TOW hook base.


Maybe it was originally like this, designed for a truck frame..




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Yep, exactly what it was originally. I have broken those hooks... On a 10 ton M123 military truck... pulling a semi trailer with 50,000 lbs of drill steel... in deep mud... with a 12 cylinder D9L Cat. The hook and 1-1/2" cable choker scratched the paint on the ripper frame.

[whtbaron]

I've never tried AC 7018s.

Coincidentally I am the midpoint of getting rid of my AC buzz boxes so I see no need to run out to buy a pack.

I've sold two Forneys and one Miller.

Still have two Forneys and one Miller to go. LOL.


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Oh no.... not the Forneys!!!

[Willie B]

I don't believe you can fix that. Weld anything that doesn't penetrate ALL the way through, it won't last.

I don't know how big that component is, whether you could bolt a used piece in its place? Could you cut it off lower where the cast isn't already broke to $hit, & weld on another section from a salvage yard?

I'm with 12V71, I'd favor Dual shield. Stay away from anything that isn't low hydrogen, & don't use filler that isn't extremely ductile. That stuff is going to shrink a great deal as it cools.

[Willie B]

I bought that back when I just had the buzz boxes so it is AC rod. I have that brand in 7014 and 6013 too, and they seem alright. I won't buy it in 7018 again though.

We are going to have to have a long talk. I'll be kind (like I would with either of my DNA associated sons, or 4 who adopted me & Mrs. B). I might say: "What in Hell is wrong with you?"

This project will require more than 13, 14, 11 series rod.

You are dealing with cast steel subjected to extreme stress. Only way to weld a crack is to completely remove ALL metal within 1/4" of that crack face. You'll be doing a very thick weld requiring many passes. Each pass will yield new & more stress as it cools.

My personal belief is Old Miner Called Pop hisself couldn't make that repair last. If you try you'll need every advantage. Cut it out WIDE, you have to weld all the way through. Preheat. Each weld pass, peen the stuffing out of it. I'd opt for 7018 'cause it is most ductile. Others might choose 11018 for strength. I'll counter "The strongest weld is useless if it tears away from the base metal as it cools."

[12V71]

I don't believe you can fix that. Weld anything that doesn't penetrate ALL the way through, it won't last.

I don't know how big that component is, whether you could bolt a used piece in its place? Could you cut it off lower where the cast isn't already broke to $hit, & weld on another section from a salvage yard?

I'm with 12V71, I'd favor Dual shield. Stay away from anything that isn't low hydrogen, & don't use filler that isn't extremely ductile. That stuff is going to shrink a great deal as it cools.

That component is part of the entire front section of an articulating front end loader. The cast steel section is welded to the plate frame that holds the front axle and many other parts. Cat cast steel is readily weldable by most any low hydrogen process. My preference is something along the line of Lincoln 71M or similar. Used to love Hobart Fabco 802 for this stuff. I've even done these repairs with ERS70-6 wire and a good preheat. Still holding to this day.

[whtbaron]

Gotta pay attention Willie. The first weld (on the arm hinge) was all Eutectic 9598 CEC... used because it's "supposed to be" stronger and more flexible than 7018. It was preheated with a rosebud, ground to within 1/8" of the bottom of the crack, and peened and had the snot beat out of it with the needle scaler and wire brushed between each bead. The 2nd weld on hook was ground until the two parts barely touched at the V. It was tacked with 1/8 7018 enough to fill the gaps, and then finish welded with the Eutectic 9598 CEC. The 5/16 7014 was just used to add metal and pretty up the transition between the 2 pieces. Both welds had 100% penetration and both welds were broke once, so I suppose the potential is there to break again... and weld again. When I bust one of them, I'll post it up here and let you laugh at me. Could be a while though...

[whtbaron]

That component is part of the entire front section of an articulating front end loader. The cast steel section is welded to the plate frame that holds the front axle and many other parts. Cat cast steel is readily weldable by most any low hydrogen process. My preference is something along the line of Lincoln 71M or similar. Used to love Hobart Fabco 802 for this stuff. I've even done these repairs with ERS70-6 wire and a good preheat. Still holding to this day.

I would weld the crack 10 times rather than change that whole hinge. To cut one out of a used machine, cut this one out and then expect to weld everything back together in perfect alignment for the arms would be a nightmare, and I can't see why my welding on the hinge is any different from welding in the entire component. Not ideal, but still the lesser of 2 evils. That was also why opted to weld with the loader in place, to make sure it was still in alignment after everything cooled.

[Welder Dave]

I don't think broken hooks that could be used to lift anything should be welded by anybody. You lift 20 things no problem and forget about the hook, then the one time you're in a jam and need to lift something the hook breaks and sends pieces flying. The hook was forged as a 1 piece assembly and being a hook I'd replace it or use a new weld on style hook.

[whtbaron]

I don't think broken hooks that could be used to lift anything should be welded by anybody. You lift 20 things no problem and forget about the hook, then the one time you're in a jam and need to lift something the hook breaks and sends pieces flying. The hook was forged as a 1 piece assembly and being a hook I'd replace it or use a new weld on style hook.

I used another hook.... what's the difference between welding it to the bucket or the bolt on base?

[whtbaron]

I would guess the previous owner welded a regular chain hook to the base of a broken TOW hook base.


Maybe it was originally like this, designed for a truck frame..




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LOL... I did a Google search of that picture to see where you found it....it was NOT helpful...

[whtbaron]

School bus parts look close.... https://midwestbusparts.com/index.ph...ducts_id=11013

https://www.buyersproducts.com/produ...hook-pairs-237

Military surplus? https://forums.g503.com/viewtopic.php?t=227812

[farmersammm]

I think it's a special hook.............one made to hold an options chain

[Welder Dave]

I used another hook.... what's the difference between welding it to the bucket or the bolt on base?

I had a longer explanation but deleted it. The fact you used 7014 on any of the hook is more than enough reason (by itself) you should just replace it. Sorry, but your welding the hook is not too far off some of the pics. under the trailer fail thread. It could potentially break and seriously injure someone. Weld on hooks are designed to be welded on (by qualified people) and don't put the weld on the highest stress point. I would get rid of both those bolt on hooks. They are made for pulling and put undue stress on the section that broke when doing any lifting or too much side pulling. My best guess is they were put on by someone who didn't know how to weld or didn't have a machine. I've never seen that style of hooks on heavy equipment. John Deere used to have really nice hooks on the corners of their smaller track loaders but I don't know if you can still get them. You could hook a chain in them or they had a had a closed oval loop.

http://twentywheels.com/imgs/a/c/f/a...khoe_1_lgw.jpg

[Willie B]

Gotta pay attention Willie. The first weld (on the arm hinge) was all Eutectic 9598 CEC... used because it's "supposed to be" stronger and more flexible than 7018. It was preheated with a rosebud, ground to within 1/8" of the bottom of the crack, and peened and had the snot beat out of it with the needle scaler and wire brushed between each bead. The 2nd weld on hook was ground until the two parts barely touched at the V. It was tacked with 1/8 7018 enough to fill the gaps, and then finish welded with the Eutectic 9598 CEC. The 5/16 7014 was just used to add metal and pretty up the transition between the 2 pieces. Both welds had 100% penetration and both welds were broke once, so I suppose the potential is there to break again... and weld again. When I bust one of them, I'll post it up here and let you laugh at me. Could be a while though...

No risk of me laughing. I've been in similar situations. I'll have a good cry on your behalf.
That area has numerous visible cracks, I'll guess metal fatigue will produce more cracks in future. It surrounds a pin under a whole lot of load. When you do weld it, distortion will cause misalignment at the pin. It'll want to be line bored.
My suggestion would be move down below the crumbled area & cut it off. There has to be a salvage condition loader somewhere with that section intact. A weld in sound steel stands a better chance of success.
As to rods, I'm not familiar with the exotics mentioned. I've seen some of the technical demonstrations of low hydrogen rod vs cellulose rod. Hydrogen embrittlement is real & this is the sort of place it's important. Hydrogen is introduced by the combustion of some varieties of flux, cellulose, a (hydrocarbon), grease, dirt, paint, rain all contribute some. Preheat helps to drive it off. Hydrogen molecules (or is it atoms?) move through steel, more easily if hot. You get a build up of hydrogen at the weld boundaries, weakening the fusion to cast in this case.

[12345678910]

At the very least, 7014 is flat position only and 7018 is all position.


It's just easier to have the more versatile 7018 around.

I keep a brick on the bench or the work for restarts.

Tappy tap, strike. One hand.