Disassemble Ark 500 loader

[giantsean 59]

Hey All,

 

I have a repower D200 with an Ark 550 (I think) model loader.  Was working it over the summer moving and grading dirt, and I have some pretty gnarly hills.  Unfortunately I lost it while moving a little to close to a bigger slope, thought about riding it down, then thought better and made the leap of faith, and watched the show.  You'd think a half a ton of tractor and loader would tear up a lawn pretty nicely, but it took it like a champ

 

But this isn't about the lawn... it's about the loader.  The tractor made it through pretty well, needed some minor work, like retrieving the battery which had flung across the yard, a little unbending of sheet metal, etc, but it's good to go.  The loader however got pretty cracked/bent/broken and needs repairin'

 

Since I weld about as well as I drive tractors on hills, I am probably going to send it out to get done right.  So now I'm trying to figure out how to strip it to the bare minimum for the broken areas.  Specifically, does anyone know how to remove the pins at the farthest back joints?  They don't seem to be bolts, and have a zerk fitting on the outer edge with a small plate which is held by a short bolt (please see pics). 

 

I know the entire frame is one piece, but what I'm trying to do is be able to send it out w/o the two uprights if possible.  There are two quick connects at the hydraulic lines but those are to and from the pump, so I imagine no matter what I'll be needing to either leave all the lines on or drain and remove a bunch of them.

 

Thanks for any info!

Edited December 21, 2018 by giantsean

[roadapples 6,983]

Unbolt the flat bar welded to the pin and tap pin out from the inside...

[giantsean 59]

Nice thanks!  So I take it there's some sort of captive bushing behind the grease fitting

 

Nevermind I see what you mean.. the plate and pin are attached and I guess the pin is drilled to let grease to flow out.

Edited December 22, 2018 by giantsean

[JoeM 7,871]

If I was making those weld repairs, I would want the whole machine. That would enable the correct fit and straightness of the repairs.

 

[giantsean 59]

2 minutes ago, OILUJ52 said:

If I was making those weld repairs, I would want the whole machine. That would enable the correct fit and straightness of the repairs.

 

That's a fair point as well.  I still have to hook up with a fixer, so I will go over it with them once it's time.  One thing that is not super clear is that the lifting cylinders have been replaced since the bottom pic, and the original mounting points have been bent outward and re-welded.  I was thinking it might be better to start with new plate and just mount it outside to increase the spacing without the angles/bending.  The trick is the port side tower seems to be a reservoir and I assume would need to be drained and maybe flushed out before any welding took place, so may not be worth it for the couple times a year I use the thing.  

 

All that said, from these pics at least, do you guys see anything that would be a challenge to fix?

[JoeM 7,871]

Just looking at the pics not much heart burn. The big money would be in pulling the frame straight, that is a little unpredictable.

As far as welding on the oil tower no big deal. I've welded on oil sump tanks. That's a small amount of weld..... just can't burn through. 

Looking at the machine and how it was before, it would be a shame not to fix it right. Plus I sure would not want it to fail catastrophically.

[953 nut 55,081]

Glad you decided to jump off rather than ride it out. Whenever you are on a hill always keep the bucket low.

If you find a welder who just wants to patch it up,   find another welder!  A good craftsman is going to want to correct the errors done by previous cobblers.

[giantsean 59]

2 hours ago, 953 nut said:

Glad you decided to jump off rather than ride it out. Whenever you are on a hill always keep the bucket low.

If you find a welder who just wants to patch it up,   find another welder!  A good craftsman is going to want to correct the errors done by previous cobblers.

The irony is that the bucket WAS low.  Part of what pulled it was everything flopping toward the down side (the other part was that a retrofitted power steering rack gives it a bit of sloppy steering geometry).  If the bucket was not on I think I might just have pulled out of the turn.  Or if I yanked the motion control back, also would have done the trick.  Even if I had just crept it instead of being in such a hurry.  The best bit of luck was that I had a jump box on the foot pads so my left leg was up on the tunnel.  If I had not been in that position, I'm honestly not sure I would have been able to jump in time.  Probably good as I'd have way more to worry about than welding

 

As for the work, yeah if I'm going to pay to fix it, I would like to improve it.  What WOULD be nice down the road is to have a ballsier pump.  This thing is supposed to be able to lift 600 lbs but I can't see it getting close.  Not sure what governs lifting ability but from what little I do know about hydraulics, pumps make a difference.

[953 nut 55,081]

7 hours ago, giantsean said:

This thing is supposed to be able to lift 600 lbs

No doubt it will if properly repaired.      I have lifted a 953  (656 pounds dry weight) out of a ditch with my FEL on a GT-14. I couldn't move too fast because the weight of the 953 was lifting the rear wheels of the GT-14 when they hit a bump. After that episode I filled the rear tires with RV antifreeze and keep the 953 out of the ditch.   

[Sarge 3,463]

From a couple of those pictures - it looks as though it has been bent/broken and repaired before, and not done very well either. Almost looks like some of the main members may have to be replaced entirely, which is what any responsible welder/shop would want to do versus trying to straighten and repair it. The plates at the pivot points that are bent are faster to make new ones rather than trying to straighten what you have, plus side is it's stronger than metal that is fatigued.  Be prepared, at a shop this isn't going to be a cheap repair either way - time costs money.

 

Sarge

[KC9KAS 4,741]

10 hours ago, giantsean said:

Not sure what governs lifting ability but from what little I do know about hydraulics, pumps make a difference.

Cylinder diameter is very important to lift strength.

[oliver2-44 9,689]

19 minutes ago, KC9KAS said:

Cylinder diameter is very important to lift strength.

Cylinder diameter and hydraulic pressure developed by the pump determined lifting strength. The higher the pressure developed by the pump the more a cylinder can lift

[953 nut 55,081]

Given the same GPM pump, the larger the cylinder diameter the more slowly it will operate. Since pressure is measured in pounds per square inch and the larger cylinder has more inches it will be able to lift more. 

[giantsean 59]

11 hours ago, 953 nut said:

Given the same GPM pump, the larger the cylinder diameter the more slowly it will operate. Since pressure is measured in pounds per square inch and the larger cylinder has more inches it will be able to lift more. 

With this unit (at least until it broke), it would squeal something awful when pushed too hard.  In fact I just found some documentation for it (or something like it) while looking through the files archive, and it sets the capacity more like 350lbs, which is a lot closer to what I'm seeing in real life... the bucket says it will fit about 5 cubic feet, which I reckon is more like 375-380, and when full of dirt mine squeals like a pig when trying to lift that much.

 

I'll get it looked at first and see how much damage the damage is    The pics do make it appear to be bent all over but the only truly bent areas are the starboard side arm in front and the mounting point of the same side bucket cylinder.  

 

Thanks again!

Edited December 23, 2018 by giantsean

[wallfish 16,985]

The squeal is the pump belt slipping on the pulleys. That allows for some loss of power. A new belt with proper tension should cure that.

Think all the Ark loaders were rated to lift 350 lbs.

Surprised there's not more damage from rolling down a hill. Check where the uprights connect to the sub-frame to be sure there aren't any cracks. I agree with OILUJ52, the shop should have the whole machine to do the repairs. Maybe add a ROPS while you're at it.

[aghead 72]

I would love to have your repair/fab job in my shop! I would def need the entire unit for correct fitment and functionality. Once I had it think I could also duplicate it and build another loader.

As for the ROPS, I've built dozens of full protective cages and belly pans for larger tractors for logging and other heavy brush work. I built "mini" ROPS for my Kubota RTV with limb risers and it weighed less than 100 pounds. I imagine your D200 GT is already pushing weight limits on the front axle. A nice ROPS would add maybe 60 lbs to the rear mostly. Limb risers and top would push to maybe 200 lbs for entire weight. Once you get the full open air cab/cage...You can't jump off, you gotta 'ride out the roll'. Usually, you cant jump off either way, it happens so fast, you are VERY fortunate!

edit: CT is I'm sure way too far away. 

Edited December 23, 2018 by aghead

[giantsean 59]

14 hours ago, aghead said:

I would love to have your repair/fab job in my shop! I would def need the entire unit for correct fitment and functionality. Once I had it think I could also duplicate it and build another loader.

As for the ROPS, I've built dozens of full protective cages and belly pans for larger tractors for logging and other heavy brush work. I built "mini" ROPS for my Kubota RTV with limb risers and it weighed less than 100 pounds. I imagine your D200 GT is already pushing weight limits on the front axle. A nice ROPS would add maybe 60 lbs to the rear mostly. Limb risers and top would push to maybe 200 lbs for entire weight. Once you get the full open air cab/cage...You can't jump off, you gotta 'ride out the roll'. Usually, you cant jump off either way, it happens so fast, you are VERY fortunate!

edit: CT is I'm sure way too far away. 

Considering I drove to Wisconsin to collect it, nothing seems too far these days... but probably yes

 

The (not so) funny thing is that this is the 2nd tractor that I rolled - and dodged - on that slope.  The first one was a Craftsman lawn tractor which slipped and then jerked up and threw itself enough off balance that it rolled straight backward.  That was a harder dodge but would have killed me much less had it landed on me.  Pretty sure if a D200 w/ an FEL fell on me, I'd be typing this with my mouth, or not at all.

 

I have since bought a ZTR that goes nowhere north of 10 degrees of slope.  I really need to invest in a walk-behind lol.  I'd move to a flat lot but what's the fun in that?

[bc.gold 3,403]

To me there is obvious presence of metal fatigue, some of those fractures show signs of rust. If it were I that were going to have that loader repaired I would have a metal shop brake me new side panels for the arms then weld them together good as new.

 

The squealing like a pig is an indication your trying to lift more than the factory rating which was preset via an adjustment of the hydraulic pressure relief valve which in most cases is an integral part of the spool valve, sometimes installed in the system elsewhere.

 

With age the relief spring may weaken in that case it may have to be readjusted by adding the manufactures suggested weight into the bucket then turning the adjustment screw in until the loader comfortably lifts with out the squeal.

 

Going above the manufactures suggested rating will void your warranty

 

Rust in break indicating total failure was immanent.

 

 

Edited December 24, 2018 by bcgold

[bc.gold 3,403]

Hot rodders building a budget high performance engine will often have the stock connecting rods shot peened.

 

Stress Concentration Factors https://accendoreliability.com/metal-fatigue-failure/

 

Virtually all fatigue failures occur on the outside surface of a part at stress concentration points or stress raisers. Examples are grooves, fillets, holes, threads, keyways, splines, welds, etc. The designer must take into account the affect of these stress raisers if the part is to provide long, trouble free service. The effect a stress raiser is directly related to the smallness of its radius. As with the micro cracks mentioned earlier which promote fatigue failure, the smaller the radius of a stress raiser, the more focused and larger are the resulting stresses. Interestingly metals with high ductility suffer little from stress raisers. The explanation being that the metal deforms and in so doing the stress induced by the stress raiser is limited to the yield stress.

Figure 3 shows a plate with a hole. The effect of the hole on the stress levels across the plate is shown by the stress curve rising as it gets closer to the hole. Every stress raiser acts to concentrate stresses at the location of the imperfection.

 

 

 

[bc.gold 3,403]

On 12/22/2018 at 5:50 AM, 953 nut said:

No doubt it will if properly repaired.      I have lifted a 953  (656 pounds dry weight) out of a ditch with my FEL on a GT-14. I couldn't move too fast because the weight of the 953 was lifting the rear wheels of the GT-14 when they hit a bump. After that episode I filled the rear tires with RV antifreeze and keep the 953 out of the ditch.   

I once cut up an old bucyrus-erie for scrap the counter weight was one solid piece weighing in at 20,000 pounds my neighbor came over with his JD loader then when he tried to pick it up both rear wheel came high into the air.

 

Jimmy had the trucker park the trailer a few feet ahead then when he hammered the throttle the rear wheels of the load both touched the ground, the loader lurched forward with the counter weight nicely placed onto the trailer ready for the trip to the scrap yard. The scrap yard was none to pleased receiving the counter weight also they were expecting to receive the KT 450 Cummings in a load of scrap.

 

If you ever come across a KT, they're often found in old Kenworths or even Versatile tractors from the 1970"s. The core value alone would pay your kids University tuition for a year. We got $12,000.00 for the core, wish I could find more of them.

 

 

Edited December 27, 2018 by bcgold

[giantsean 59]

I called a couple of places and was shocked to learn about how many businesses wanted nothing to do with this kind of repair or do small walk-in repairs only... I guess they mostly weld railings and not machines lol.

 

I managed to get it partially disassembled and the uprights and subframe actually look ok.  I will try to drag the whole thing in once I find a shop but worst case if I could get the arms reasonably straight I think I may be in business.  Will report back once I have more info.  Happy New Year everyone!

 

[bc.gold 3,403]

Removing old welds to separate parts, angle grinder for a light weight job works alright, as your nearing through the cut you'll notice as the metal become paper thin a color change taking place.

 

Air arc has been around for a very long time, often used for gouging a work piece in preparation of welding or removing old welds.

 

I also own an arc loader and to me it looks like a production weld with little or no preparation, the two halves are simply butted together then surface welded when they should have been V'eed out before welding.

 

Like to hear from some of our welder members, what do you think would be the best method to weld the two re-manufactured halves together, Stick, Mig or Tig

 

I'm going with Tig.

 

 

 

Edited December 29, 2018 by bcgold

[bc.gold 3,403]

Just came back from the shop, taking a few measurements off of my Arc 700, the thickness of the metal used on the side arms is a bit of a shocker.

 

Side arms .183" measured over over a painted area, butt welded no penetration showing on the inside seam and I can grab a fingernail inside the seam.

 

 

Edited December 29, 2018 by bcgold

[Sarge 3,463]

At .183" - that is roughly 3/16" steel. Yes, a bit on the light side to some, but if designed properly it should be more than sufficient to handle the stress. To make a repair that is as strong as the base metal parts, the joint should not be a 90* cut across the tubing, but rather a 35-45* cut to increase the joint strength. It is quite common to see factory welds that are not properly penetrated down into the root of the joint - many plants hire folks off the street that have little or no welding experience. A certified or at least experienced welder would never accept just covering over a joint like that - it should be beveled at the proper angle and welded hot enough with the correct technique to get full penetration down into the root of the joint or beyond. In my opinion, a joint like that should be a full-gap weld - not something most plants with novice welders are capable of performing.

 

If you're hunting for someone to weld those parts back together - start hunting around for some of the tradesmen that may be off this time of year. Pipefitters and some Boilermakers might be off the cycle of rebuilding power plants and doing pipeline jobs - you can check with their local halls for some of the locals that might be around. All those guys are certified and excellent welders since they do pressure work and many have their own portable rigs. You'll see Pipefitters all over - custom-built trucks sporting a Miller or Lincoln welder on the back of a flatbed that looks like it's built to handle an Apocolypse. Be polite and ask if they want a cash side job doing some portable work - might get lucky. Otherwise, find an old hole in the wall looking shop that works on farm equipment - those guys have to know what they're doing to stay in business. You'd be welcome to drag it here if you want - I'd do it for the cost of supplies, but that's going to be a long trip.

 

Sarge

[bc.gold 3,403]

Metal Fatigue is actually caused by hydrogen then over time as the metal ages the embrittlent penetrates deeper in the metal, fractures soon appear and tear like paper.

 

And this is the reason I suggested that the Op sourced out a shop that is capable of making new side arms for his Ark loader,

 

Hydrogen embrittlement https://en.wikipedia.org/wiki/Hydrogen_embrittlement

 

Hydrogen embrittlement is the process by which hydride-forming metals such as titanium, vanadium, zirconium, tantalum, and niobium become brittle and fracture due to the introduction and subsequent diffusion of hydrogen into the metal.

 

Susceptibility to hydrogen-induced cracking ('embrittlement') is often a result of the introduction of hydrogen during forming, coating, plating, cleaning, and finishing operations, often referred to as 'internal embrittlement'.

 

Hydrogen also may be introduced over time (so-called 'external embrittlement' through environmental exposure (soils and chemicals, including water), corrosion processes (especially galvanic corrosion), cathodic protection, and/or from hydrogen generated by corrosion of a coating.

 

To be susceptible, a combination of three factors is required: presence of (and diffusion of) hydrogen, susceptible material, and stress.

 

For susceptible materials (such as coated high-strength bolts, where hydrogen is often present after manufacturing and may also be added over time by cathodic protection, galvanic connections, etc.), cracking will initiate when a sufficient stress has been reached; this is known as the threshold stress or Ki_SCC.