Case/Davis trencher backhoe

[Eugen]

Valve off, spools out, o-rings measured and order placed. Getting size -114 and -208, ID 5/8, cross section 3/32 and 1/8, durometer 70a.

I'm not splitting the sections though. Anything else you guys think I should do to it?

[DavidBarkey]

@Eugen , just make sure you cover all the basics. Make sure there is no rust in the end of bores / seal grooves and is clean. Same with spool ends , clean , no rust or burrs.

[Eugen]

@Eugen , just make sure you cover all the basics. Make sure there is no rust in the end of bores / seal grooves and is clean. Same with spool ends , clean , no rust or burrs.

Thanks Dave! I also paid attention to keep each spool in the original location.

[Eugen]

Well, the leaking spool being a minor setback, last night I became aware of a major setback, and it's connected to the actual backhoe. The D100 backhoe was really the reason for getting this whole machine, and my original plan was to mount the backhoe to one of the 644s. Getting the crawler running was not in the plan, so it turned out to be a nice bonus. So, back to the backhoe. I made a costly mistake: installed the boom cylinder in the wrong orientation. One of those moments when I was looking and there was a fleeting thought that it should be installed with the hose connections towards the bottom like this

yet, for some reason, I installed it with those connections upwards. The dipper cylinder gets installed on top of the boom cylinder. The net result was that when the backhoe arm goes straight, that is, when the dipper cylinder extends, the big bump on the upper side of the boom cylinder stops the dipper cylinder from moving downwards. As I briefly tested extending the backhoe arm, the dipper cylinder extended and bent the rod, not being able to move downwards. Not cluing in fast enough, I retracted it. But then, realizing this was the case, I extended it again so I can have it in position to pull the bent rod out to fix it. But the bent rod in itself isn't the major setback. The real problem is that the bent rod pushed the piston into the side of the barrel so hard that now there's a big gouge, about 3" long and 3/4" wide at the bottom. Pretty deep by the looks of it.

Of course I'd like the keep the original cylinder, but a new one from PA is about $230. I don't like it, but I don't really see an alternative.

[DavidBarkey]

that sucks.

[Eugen]

Does it ever!

Punishment for screwing it up is to cut it open and try and fix it.

Now the gouge is within reach, like 3" from the cut off end. JB weld anyone?

Maybe just real weld on top of the gouge and then clean up with the die grinder and polish? It kinda has a tiny chance it might work.

[DavidBarkey]

@Eugen in this case I would say no to JB Weld . What size is the barrel. ?

[Eugen]

@Eugen in this case I would say no to JB Weld . What size is the barrel. ?

yeah, I was kidding about jb weld. 3 inch bore, about 22 inches long. I'm thinking splatter could be an issue, requiring more grind cleaning. Maybe I'll pick up an anti splatter spray and apply to the inner barrel except for the gouge (masking tape). I'm also thinking 7018 stick DC because one, it reaches easily inside, not like the mig, and it splatters the least (for me). It'd be nice to turn the inner weld bump on a lathe after the initial welding, but I don't have a steady rest for my lathe and the piece may not fit anyway.

[DavidBarkey]

@Eugen in this case I would say no to JB Weld . What size is the barrel. ?

yeah, I was kidding about jb weld. 3 inch bore, about 22 inches long. I'm thinking splatter could be an issue, requiring more grind cleaning. Maybe I'll pick up an anti splatter spray and apply to the inner barrel except for the gouge (masking tape). I'm also thinking 7018 stick DC because one, it reaches easily inside, not like the mig, and it splatters the least (for me). It'd be nice to turn the inner weld bump on a lathe after the initial welding, but I don't have a steady rest for my lathe and the piece may not fit anyway.

agreed. same here on my lathe . boring and honing after welding would be ideal .
You could make an align bore cutter . picture alarge steel rod with a bracket attachhed in the middle ish that held a cutter with bushings on each end to center in bore of tube . cutter is set to take a bit at a time untill only a few thou let so as not to mark the rest of cylinder . powered by large drill . then hone to size and finish .

[Eugen]

@DavidBarkey I was thinking of a ridge reamer to do the preliminary boring. Do you possibly have one?