Bobcat X-change parts. Are they cast iron? or cast steel/ductile iron?

[LD1]

Going through all the pins and bushings related to the bucket and thumb on my 334 (same as a 331 but longer arm).

The two straps (~3/4" thick) on the sides hook to a cast like H shaped piece. Said piece I have tweaked....when the retainers for the two side straps flew off. Resuling in bending and twisting them and the H-shape piece.

Though it was a fluke. Fixed it, reinforced the side straps.....but it happened again. I was successful both times straighting (untwisting) the cast piece with some heat and the machines own hydraulics.

Im figuring there is just too much slop and binding til something lets go. Hence going through the pins and bushings to tighten things up.

Bobcat is proud of that cast H shape piece. They want about a grand for it. Was thinking about welding on some stratiegically located pieces to resist twisting. But don't want to mess with it if its cast iron.

The coupler itself also looks cast.

Here is a pic I found online. It dont have the xchange coupler....but looks the same otherwise.
Red arrow is the H-shape cast piece that I have twisted twice.
The green arrows are the side straps. The pins are welded to one....snap rings on the other. Something is putting a bind on them causing it to want to pop one snap ring off.....then it twists.

 

[Jkott]

I bought an abused X about 5 years ago. The pins on your Green arrow piece were worn, so I had a local welding shop (recommended by the local Bobcat dealer) cut them off and welded new ones on. They even drilled it for the grease zerks. This went back together okay until I replaced all the bushings with new ones. The H also had a crack starting in it and welding that warped it slightly. The tolerances after replacing the bushings were so tight that I couldn't get it to all go back together. I ended up just dropping the entire machine off at the local welding shop to bend and tweak parts they worked on until they fit. From the pics I have from 5 years ago, it looks like they heated the center of H and twisted it back into shape. They made everything fit and move nicely. It's been over 5 years now, and the welded and heating to twist the H is holding up just fine.

IIRC, all the welding, new pins, and straightening was only a couple hundred dollars. Far less than buying new parts.

New bushings and welding, there wasn't enough slop for the pin now

New pins and welded H

 

[LD1]

I just finish up yesterday on mine. Re-made several bushings and pins. Didnt have to touch that H shaped piece. So still unsure weather its Cast iron or something else.

Most of my slop were at the single long pin....that goes through the end of the dipperstick through two bushings in there, goes through the coupler, and also the thumb.

The bushings in the x-change coupler were shot and the holes egg shaped. I think the coupler is cast iron??? IT has been worked on before....the egg shape bores for the main pin that attaches it to the dipper....have been welded a bit. Not sure if they were welded in an attempt to make true....or the bushing were welded in to take out the slop. I tried to use an expandable reamer to make the holes round again then I was gonna turn some oversized bushings.....but....where it was welded was hard as diamonds. Which is typical of welding cast iron with a mild steel rod. A file wouldnt touch it. And a carbide burr didnt like it either. So I repeated what I think was done in the past, and made new bushings....then welded them in...and reamed to size. Welding them I hope so they dont loosen up and accelerate wear since I couldnt get the holes perfectly round again.

Also made new bushnings and a new pin for where the H-shaped piece attaches to the coupler. Its the pin with the tab and notch welded on (you can see in your pic).

The two pins (welded to one of the side straps) and associated bushings didnt seem sloppy enough to warrant replacement just yet. So I'll save that for later if I decide it needs tightened.

The bucket (or I should say bucket coupler) is nice and night now with no free play. Yet still moves smoothly and easily with no binding.

The only bit of play now is just the coupler to the bucket. And thats just the nature of a quick attach system. IF they are too tight you fight swapping buckets.

 

[Jkott]

Neighbor had a machine shop, so we used his Bridgeport Mill to true them up and then made inserts.

People that don't grease their **** shouldn't be allowed to operate it.

I think my bucket is pretty tight after you put in the pin. You might be able to shim the bucket a little to tolerances are a bit closer.

 

[LD1]

Neighbor had a machine shop, so we used his Bridgeport Mill to true them up and then made inserts.View attachment 696067View attachment 696068
People that don't grease their **** shouldn't be allowed to operate it.

I think my bucket is pretty tight after you put in the pin. You might be able to shim the bucket a little to tolerances are a bit closer.

Yep, those are the holes on the coupler that someone previously welded to.

Way to hard to machine with HSS and even too hard for carbide.

In mine, the insert/bushing that goes in there is like a flange bushing. With a 3/8" thick flange on the inside. Because the coupler is 3/4" wider than that H-shaped piece that the pin goes through.

So I made some that fit my oval holes tight.....welded them inserts to the coupler, and reamed the ID to the pin size (1-3/8").

I have a bridgeport and a 4500# lathe. So I do my own machine work.....otherwise this would cost a fortune. As it is....it only cost me time.

Some of my buckets fit tighter than others. There is a little wiggle, but not a ton of slop. Not bad for a 3000hr machine. I think most of the slop isn't wear from lack of grease.....rather years of use egg-shaping holes.

Prime example is the swing post. Which is seldom used on a mini....only when using the slew cylinder. If I put boom down to lift machine.....those pins/bushings mine probably 1/8" or a tad more taking the slop out before the machine actually lifts. Not even noticable in operation....so I'll probably leave them alone.