Need advice on weld joint prep

SteveF · Dec 25, 2022

Need a little advice on a small repair job. The shaft welded to the side of the loader that supports the lower bucket arm has a very small, hairline crack on the bottom. This part of the machine forms the side of the hydraulic oil tank so the hairline crack is allowing oil to very slowly leak out. I’m not concerned about the leak, I’m concerned about the crack making a stress riser that will eventually cause the shaft to break off.

I “assume” that this shouldn’t be welded with oil in the crack. No problem to drain out all the hydraulic fluid. What would folks suggest for how to clean inside the crack and prep the joint?

Yes, I am having this welded by a professional shop. It’s just that many years ago I took a broken clutch arm from my Mustang to a “professional” shop to see if it could be welded. The guy said “Sure, I can do it right now”. I said “But it’s all filthy and covered in grease and dirt. Let me go home, clean it and bring it back”. He said “Nah, the heat will just burn off all that grease and dirt”. His weld lasted less than a year and I learned that just because someone does something for a living, doesn’t mean you should trust their advice.

Thanks.
Steve

empower · Dec 25, 2022

propane torch to burn out the oil. you still wont get it all the way out though unless you grind the crack all the way through then fill it back up.

plastikdreams · Dec 25, 2022

Drain the tank, grind out the crack, clean well inside and out...fill it back up with weld. That's the proper way to do it.

dkmc · Dec 25, 2022

I think that warrants nomination for some kind of 'poor engineering' award.

gbent · Dec 25, 2022

IMO, the correct way to fix that would be as Plastik states then put a round reinforcement around the shaft and weld it to the tank. Then make a snug fitting collar for the shaft and weld that to the reinforcement, but not the shaft. The shrink from welding will make the collar quite tight on the shaft. Yes, I know you will have to cut the welded retainer off the pin to remove the cylinder, and there may not be room to install a collar. I also suspect there is no way to properly clean the interior of the tank after welding.
What exactly is this tractor/loader?

TheOldCar · Dec 25, 2022

I wonder how thick the tank plate/sheet/panel is?
Does the shaft really end there, or is there any crazy chance it extends through the tank to heavier framework?

SteveF · Dec 25, 2022

It’s an Allmand TLB325. The steel plate is 1/4”. From an exploded diagram looks like they drill a hole in the plate. Insert the end of the shaft slightly into the hole and weld it. There isn’t any way to easily add reinforcement and since the other three are fine and this one failed right where they started/stopped the weld I’m not worried about it beyond getting this rewelded properly.

rons · Dec 26, 2022

SteveF said:
His weld lasted less than a year and I learned that just because someone does something for a living, doesn’t mean you should trust their advice.

It's no different from PM. There is a small review board that thinks they have the right to defend the chastity of PM.
In the real world they are deeply offended by new-combers with fresh ideas that didn't come out of one of their books.
In the real world the ones who complain the most are the ones least deserving of whatever they are mouthing off about.
They also give the weakest advice too. A person in the middle east would look at this PM site and not be surprised about the behavior.
Would probably say "no wonder the bastards can't win a war that they start".

I've been to local shops, one in Santa Cruz, local tool supplies. Not once has somebody known about PM.
They are too busy to give free advice or bother with PM.

Your welding problem would look better built if you add more material to the joint.
Otherwise it is a point of failure. And will probably continue to behave the same.

memphisjed · Dec 26, 2022

That was a robot weld, hard to repeat its strength.
Clean tank, grind weld down, grind out the cracked area, weld up. Two rectangle plates with semi-circle as scab/stiffener plates over that weld. These plates would be .25 or .1875 thick and go to .25 “ from the flanges of tube tank. Dissipates stress and pawns load onto flange.
This is not an odd ball repair.

SteveF · Dec 27, 2022

Thanks for the replies. I appreciate the info.

farmersamm · Dec 27, 2022

From your pic, the weld is leaking. Not the shaft cracked, and leaking. At least, looking from here. If the shaft doesn't extend through the tank, to the other side, I can't see how it would crack. The load on the shaft would distort the plate before it cracked.......if it wasn't a through and through shaft.

Your red arrow doesn't indicate a cracked shaft, it indicates a bad weld.

Porosity, or other discontinuities, in the weld would cause it to leak. Underbead cracking would cause it to leak.

Drain it, attempt to clean the area with solvent, then weld it. If it doesn't hold(air test), then heat the thing to drive the oil out. I don't like putting heat to an enclosed area with volatile fumes in it. It would be my last resort. Hell......just the heat/depth of fusion of the weld in an enclosed area is a safety risk.

It's also possible to run a weld over the offending area with oil in the tank. Much safer.(my number one choice) The weld might hold, it might not. You'll find out right away. Eventually, after a few tries, it will hold. From here, it just looks like a pinhole where the red arrow is.

farmersamm · Dec 27, 2022

SteveF said:
It’s an Allmand TLB325. The steel plate is 1/4”. From an exploded diagram looks like they drill a hole in the plate. Insert the end of the shaft slightly into the hole and weld it. There isn’t any way to easily add reinforcement and since the other three are fine and this one failed right where they started/stopped the weld I’m not worried about it beyond getting this rewelded properly.

Where are you finding that detail. I looked at https://www.allmandtractorparts.com.../IPL-TLB-535-425-325-220-225-PARTS-MANUAL.pdf and didn't see it. The drawing actually looks like a pin boss.

cyanidekid · Dec 27, 2022

rons said:
It's no different from PM. There is a small review board that thinks they have the right to defend the chastity of PM.
In the real world they are deeply offended by new-combers with fresh ideas that didn't come out of one of their books.
In the real world the ones who complain the most are the ones least deserving of whatever they are mouthing off about.
They also give the weakest advice too. A person in the middle east would look at this PM site and not be surprised about the behavior.
Would probably say "no wonder the bastards can't win a war that they start".

I've been to local shops, one in Santa Cruz, local tool supplies. Not once has somebody known about PM.
They are too busy to give free advice or bother with PM.

Your welding problem would look better built if you add more material to the joint.
Otherwise it is a point of failure. And will probably continue to behave the same.

wow, what are you on? sounds good, send me some...

DrHook · Dec 28, 2022

I can't see the leak source in those photos, but if you are certain it is the start/stop of the weld, I would drain the tank, clean with brake clean and compressed air. Since it probably a "flex" issue, I'd go with TIG silicon bronze.

farmersamm · Dec 29, 2022

First off, these are, as I thought,...................simply pins that go through the loader pylon. No stress risers involved in the weld to worry about causing the pin to break. The pin has nothing to do with the weld. They're separate entities.

Crack in the plate adjacent to the pin boss weld? Maybe, but the pics don't show enough detail to be able to see one. It is entirely possible, just sayin' the pics don't show it. It's an area that takes a cantilevered load.

If closer inspection shows the plate to be intact, it's pretty much a blob and glob deal if you decide to weld it(oil level above leaking area). If welding gives you the heebie jeebies.......drain the tank, clean it up, and silicone the sucker.

IMHO

farmersamm · Dec 29, 2022

Like I said.........welding with tank drained would be my absolute last resort. Once drained, you have oxygen mixed with the hydrocarbons............takes O2 to cause combustion. When the oil level is above the leak, no O2 in the weld area inside the tank.

If it isn't structural, any welding is simply sealing. If the weld isn't x-ray perfect,, it doesn't matter. It's like sticking chewing gum over a hole.

SteveF · Dec 29, 2022

Thanks for taking the time to review this. I've got a guy coming over to weld it this afternoon. He's a retired pipeline welder who also said not to drain the hydraulic fluid. Although after the work is done I'm going to drain the fluid and replace it since it's due for a change anyway.

Thanks again.

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