Case 580K front bucket top pivot ripped out!

[Tinkerer]

Does that mean the tube is broken off also?

Willie

I would think so. If you look at his photo of the broken side, it appears that there is a flange welded to the tube. That is exactly how the tube in my 680C is attached to the hydraulic tank. That is why I think there is a good probability that the pin could be bent on the opposite side. If the wall thickness of those tanks is very heavy I would look for the bend between the loader frame and the flange that is welded to the tank. If the tank wall is kinda thin, then the tank wall is just bent somewhat and the pin is OK. It will be interesting to hear what he finds when he gets it apart.

 

[mhobson]

Here are a couple more pictures:



The 4 inch tube goes from one side of the digger right across through the inner tank wall, and should be joined, I suppose, but no longer, to the back of the detached plate. Where it passes through the inner tank wall the weld seems intact and there is no sign of movement, there is no sign of damage or bending the the 4 inch tube. The wall of the tank seems to be made from 5 mm (3/16") plate.

I may be some time in making more posts in the near future as it seems the repair could be very expensive and my finances are very limited at the moment, I cannot afford to just take it to an agricultural repair specialist. I would like to do as much as possible myself but the issues I have are finding something to support the forks which after the repair has been done can be adjusted to allow the refitting of the top assembly shaft (about 2" dia). I have not yet found a rentable A frame big enough around here. After that I need to find a proficient welder, who is prepared to come here and reconnect the plate. Around here most of the welders have 3 phase welders but we only have single phase. I have a 170 amp MIG welder but the circuit board has just died and that model is not being made anymore so a new board is not available. I will update when anything is worth mentioning. I thank the members for their very valuable input.

Michael

 

[Willie B]

I seldom rent. Iron is cheap compared to rent. three pieces of steel makes a tripod. Six with a cross bar makes a reusable hoist. A couple come alongs support the weight.

Consider junk yard frames. With the equipment I have here available this would be a weeks fun in conquering a challenge. Without equipment, it looks like misery, with failure the likely prognosis. Sell it, or hire it fixed, (be very careful who you hire), or buy a used part.

Consider cutting both tanks off, make the repair, and reinstall. Cleaning will be the nightmare,

Willie

 

[Juskatla]

I looked at the parts diagram and the loader frame appears to be a single unit. If the opposite side is still intact, I'd be inclined to cut the shaft on both sides to get the loader arms free, blocked and back the machine away. From my limited experience, I think a repair gusset plate will be required on the side that has broken out. A good welder could place the broken out bearing piece into a plate fitted to the reservoir side shape. Set the plate on the side, run the new cross shaft through and tack in place. A full weld around would spread the load over a larger area. The cross tube should probably go right through but its a large enough diameter that a sleeve could be installed to seal off the fuel reservoir part if you can't weld to the end of it.

 

[Tinkerer]

I looked at the parts diagram and the loader frame appears to be a single unit. If the opposite side is still intact, I'd be inclined to cut the shaft on both sides to get the loader arms free, blocked and back the machine away. From my limited experience, I think a repair gusset plate will be required on the side that has broken out. A good welder could place the broken out bearing piece into a plate fitted to the reservoir side shape. Set the plate on the side, run the new cross shaft through and tack in place. A full weld around would spread the load over a larger area. The cross tube should probably go right through but its a large enough diameter that a sleeve could be installed to seal off the fuel reservoir part if you can't weld to the end of it.

You and Willie are both right, that loader frame has to be removed. The reinforcing plate that you are suggesting HAS to be welded to the outside of the repair. The end to end dimension of the tube cannot be increased or the loader will not go back on.

 

[oceanobob]

We removed the (rear) bucket on the backhoe and then pulled the pins on the front loader bucket. It was a 4:1 so we had to disconnect hoses and cap 'em w some JIC plugs/caps. Then we drove the tractor carefully (we thought it could rear back due to no weight on front) to the work location (flat dirt, not concrete slab) and disconnected the loader arm rams and bucket rams etc and then drifted out that big hinge pin. Some 2x/4x teepee monkey carpentry and a rope come along and two men, we moved/dragged the loader arm. Once away from the tractor, it was be readily flopped around by one man.

We got this assignment on two different Ks to fix the metal 'boss' in the loader arm, not the chassis such as this shows. If the loader arm is not aligned it can be corrected perfectly: the rosebud and spray bottle got it 'on the money' w no red hot metal. [Ref Lincoln manual of Arc Welding]

We added a circular 1/4" plate to act like a psuedo stiffener and stitched it because that big circular weld repair isn't going to be a back gouged full pen and thus it would benefit from reduced stress/strain, and yes we back step welded it. Also preheated a little, peening a bit, rotary file starts and stops, etc. All done with 7018 from an oven. The pin was used to hold alignment during the welding and yes it drifted in a little stiffer but quite doable.

From memory the plate steel being thinner than the boss added to the welding trickery as the arc tended to cut it away (sign of too hot) but the big metal wanted some more heat....prolly why the factory uses mig and why the welds in the pics in this thread show some bead sagging. Sagging doesnt concern me as much as undercut. Stringers likely better than weave when the QA requirements get tightened. Sometimes small rod can help with this and I mentioned a bit of preheat helps too as mentioned.

****
Q: As to the non combustible atmosphere: do CO2 fire extinguishers accomplish this task?

 

[Willie B]

I'd bet Co2 will work, but that'd be an expensive way to get it. I'd bet a big tank of CO2 isn't as prohibitive in cost as scrapping a tractor.

Willie

 

[El Hombre]

In the US, the mobile weldors will have a diesel generator to power all the electrical welding machines; I'd think they'd do the same in Europe. Only an industrial location will have 3 phase, and they will probably have their own repair guys to weld something up. So the mobile guys have to be completely self sufficient. So call the mobile guys and see what they need from your site, probably access and that's it.

I watched a mobile guy cut the worn drive sprocket teeth off a D8, and then MIG weld a new toothed ring onto the hub. All of this 5 miles from the nearest power pole, just his truck.

 

[mhobson]

A bit of a delay as I had a lot of other things to do. I bought a couple of chain hoists, attached them to purlins in our garage, removed the inner circlips from the front pins of the lifting rams, tapped them through a bit, dropped the front bucket, supported the lifting rams by a rope across the bonnet, disconnected and blanked the other 4 hydraulic hoses, connected the hoists by ropes to the back end of the forks and took the weight of the forks. I then drifted out the lift ram pins. The big problem was getting the long rear pivot shaft out, it took ages. I then reversed the digger away from the forks, it was a very tight fit.

So now I am hoping for advice again. It looks like your suggestions about the digger having had a hard life are proven on inspection it seems that the principal support for that pivot plate was not the weld around its outer edge but halfway in where it had been welded in the factory to the tube which runs from side to side and which it now elliptical, it seems that that weld was broken years ago and the plate was welded back just around the edge, and those welds seem to have had very poor penetration. The original weld to the inner tube must have been done at the factory, there is no way of accessing that space now to re-weld it, there is no play available on the pivot shaft so an external plate cannot be added. It may be possible to weld a plate inside, narrow enough to get in the hole but even then you would not be able to connect it to the pivot plate, therefore my plan is to rely on having the pivot plate professionally welded around the outside edge with correct penetration.

Once welded I have big concerns about getting the forks back on. As I said the forks were on very tight, driving forward I am concerned about the forks slipping and smashing the lower windows, after that I am concerned about how to get the long pivot shaft back again, I can't see much chance of getting the fork bearing in line and sliding in from one side, even though there is a dimple in the end of the shaft, lining it up that way looks like a nightmare, is it possible to install it before driving the digger forward and then fit one side at a time? The bearings are quite long and I don't know if they could cope with the degree of twist necessary.

Thanks,
Michael

 

[mhobson]

Photo's of fork removal, pivot plate hole and pivot plate.

 

[hosspuller]

Michael ... The only advice I can give is connect the hydraulic lifting rams first. Then you have a way of using the machine to move the loader "fork" in a controlled manner instead of driving into them. (and smashing your window)

 

[Willie B]

Restore it to its design. Cut around the inner tube, and at the most convenient point, cut it off. This will expose the inner break, so it can get a proper repair. Some reinforcement would then be possible on the inner tube. Put it back in place, and weld all three places. It seems likely you'll have to do the other side at this time.

Willie

 

[Delmer]

If you're feeling lucky, you could try welding that inside joint with a bent welding rod and a mirror. Better than leaving it the way it is. Or like Willie says, cut the flange off the inner tube and weld the tube, then the flange around the tube.

I still say the other side is showing a crack in the pics, weld that at least. Use a mirror to inspect the inside of the tube for cracks in the same location this side broke.

Use a jack or winch to pull the tractor back into place if you're worried about the windows. That's the easy part. Sharpen the end of the pin if needed to help it aid in the alignment.

 

[mhobson]

Michael ... The only advice I can give is connect the hydraulic lifting rams first. Then you have a way of using the machine to move the loader "fork" in a controlled manner instead of driving into them. (and smashing your window)

Mmmm, I see your point here however I wonder how it would work, I suppose the rams will have to be extended then juggling the load with the hoists may be diificult and I would have to insert the long pivot pin from one side which worries me

 

[mhobson]

Restore it to its design. Cut around the inner tube, and at the most convenient point, cut it off. This will expose the inner break, so it can get a proper repair. Some reinforcement would then be possible on the inner tube. Put it back in place, and weld all three places. It seems likely you'll have to do the other side at this time.

Willie

The only internal break is where the inner tube was welded to the pivot plate, because it is a closed box I can see no way of accessing that weld, the only possibility I could think would be to get the bearing removed from the pivot plate by a specialist engineer, welding outer and inner (the weld would have to be made about two inches deep through a hole of less than rwo inches in diameter) and then the hole would have to be line reamed to remove excess weld and then press refitting the bearing, all of that frankly is out of my league in engineering or financial terms.

 

[fast_st]

My guess is that the through bolt was allowed to get loose, transferring the strain to somplace it didn't belong. Still uses a big long bolt all the way through the top pivot?

 

[Willie B]

Pop the filler door. You have access from that side. A cut around that hub, and one through the cross tube allow you to mate the two halves of what passes through the tank. You can repair these two pieces on a table, then reintroduce the mated halves to the tank. One welds from outside, one from under the service door. It's a chore requiring skills you may not possess, so professional work might be too expensive.

The project will make lots of sparks, grindings, and spatter. Protect your glass, paint etc. How you'll then clean the diesel tank, I have no perfect system. I believe there is a bolted on plate near the bottom to get in. It might be possible to stuff it with strips of cloth just below your weld, you could pull out later through the filler neck, though that too seems risky. Mechanics use cattle magnets in these tanks. I haven't seen the older style 3" long 3/4" diameter cylinder with rounded ends in years. Farmers feed them to cows. They stay in the first stomach, holding steel debris away from the intestines.

Willie

 

[mhobson]

Hells teeth Willie, I have no knowledge of anyone around here with your engineering skills! For me just cutting away the weld underneath where the crosstube joins the fuel tank, let alone welding it after repair along with the cut crosstube would be a nightmare, fuel filler and brake cylinder and pipes cluttering the area as well. I must be a wimp but I have used the digger for 6 years, it is clear that the weld from the tube to the back of the pivot plate has been broken for ages and the digger has been relying on a very poor weld around the outside edge, if I get the plate rewelded properly around the outside with good penetration I hope it will keep me going until I sell it and at 26 years old its value is dropping fast, but thank you very much for the benefit of your exceptional experience.

Regards,

Michael

 

[mhobson]

My guess is that the through bolt was allowed to get loose, transferring the strain to somplace it didn't belong. Still uses a big long bolt all the way through the top pivot?

Yes still long pivot shaft maybe 30" long, I think the damage was caused by idiot driving, the inner and outer welds breaking at the same time but the owner just did a very poor repair just welding the outside edge with very poor welds with negligible penetration.

 

[Willie B]

Is there evidence of grease in the fuel tank? Maybe not. I'm no engineer, but I HATE doing things twice. Removing a 9" long piece of the cross tube would give adequate access to cut, then weld the inner bushing. Putting the cross tube back could be accomplished by cutting a slot 1/4 its circumference. Then 3/4 of the two pipe welds could be accomplished from above on the inside. I think you might make a repair only on one face. The engineer who designed it in the first place didn't think that was enough. We don't know what level of abuse the machine suffered, we do know with the tube intact, it didn't hold. Expecting it to hold with only one face supporting it seems questionable.

Those without good conscience would effect a cosmetic repair, and sell the tractor.

Willie