JD 120 general rebuild thread, bushings, pins, CWS thumb wedge QC bushings, hoses

Link to Ebay bushings for JD/hitachi 120 boom.
https://www.ebay.com/itm/184480220192

I'm back at the yard picking apart the 120. Today's task replace the wiper motor. As usual it seems like everything is revealed once you remove the ashtray screw!

I got it in there and wanted to run it before closing it all up. I had no function and that stumped me until I realized that no, it is not going to work with the window up
What was funny was how I spotted the very well hidden interlock switch, it is a totally out of sight plunger inside the right latch pin socket. Wiper motor works but washer does not. While I had the motor out I fished the hose for the washer out, the nozzle bit had been broken off and it fell down inside the double wall of the cab. I'll figure that out tomorrow.
The wiper motor shaft was broken off by bucket to cab interference. The CWS 3' bucket can hit the wiper arm if fitted with twin tiger teeth.
When I inherited the machine the arm was behind the seat with a bunch of other garbage.

I got the 5 worst main hoses replaced today from boom to valves. it also got me in there really looking around and i have pilot hoses that need attention too. I need to set the boom at a few angles and see if I need to clock the hoses a bit. i think i have the valve ends OK.

I picked up 130# of 3/8" AR400 to armor and repair all 3 buckets. They all need a little attention. I took the plate out to a friend's with a decent plasma cutter to rip it into strips.

Mild steel does not open up like that when you rip it.

I started with the two foot bucket and scarfed off the destroyed wear plates on each side. I figured I would start smaller.
I don't have a lot of big tooling to repair my 4-ft cleanup bucket, so my plan is to scarf off all of the worn out wear plates, and then pick the one and that's most lined up with the dented in bottom of the bucket. Pop a hole through the bucket in the middle of that wear strip location, use some 6-in channel on edge that I have and make a pull fixture using some 7/8 coil rod I have and a nut. Heat it up, beat on it, and tighten up the nut until I get it as flat as I can.
I'll pull all the tooling off and put new wear strips on it and I will plug weld that hole back in the middle.

I got one of the strips on the 2 foot bucket edge. 3/8" by 3" strip of AR400
Lots of rosebud and 4 pound hammer.

I got the sides on the cleanup bucket today.
Scarfed


Cleaned up with the grinder



The other side finished



Had a funny thing happen. I ran out of acetylene and was getting ready to go to town for more, and i remembered doing a lot of cutting on the farm with oxy propane 40 plus years ago.
I found a 20 pound bottle and got back after it. My guess is about 1/3 as many BTU from the rosebud, but it was enough to heat the 3" wide strip to an even dull orange -brown. I only had about 6" to blacksmith into place so that saved me an hour plus round trip to get the high octane stuff.

I have a job to do Tuesday with the 120. When i get it back to the shop the plan is to scarf off all those worn off cross strips and then make a slicing plan so we can straighten the bottom. I'll torch slice it and then clean the slices up with a grinder.

skyking1 said:

I got the sides on the cleanup bucket today.
Scarfed
View attachment 239927

Cleaned up with the grinder

View attachment 239928

The other side finished

View attachment 239929

Had a funny thing happen. I ran out of acetylene and was getting ready to go to town for more, and i remembered doing a lot of cutting on the farm with oxy propane 40 plus years ago.
I found a 20 pound bottle and got back after it. My guess is about 1/3 as many BTU from the rosebud, but it was enough to heat the 3" wide strip to an even dull orange -brown. I only had about 6" to blacksmith into place so that saved me an hour plus round trip to get the high octane stuff.

Click to expand...

Pick up an oxy-propane rosebud and a no. 3 cutting tip for oxy-propane to stash in your tool box for those days you need to switch. They're cheap enough (under $100) to sit on. You'll get great performance out of the propane with the correct tip on the end of your torch. The same as acetylene? Maybe, maybe not. Guys claim they like a propane rosebud better than acetylene. I can't attest to that as I have only used it in cutting applications. Properly set up with the correct tip, I was very happy with the performance of oxy-propane for cutting steel up to 1 inch. There was a learning curve though for lighting the torch, but welder Dave and tugger2 gave some solid tips on how to light the torch most efficiently by setting the tip at an angle against the work surface and adding in the oxygen. And propane is considerably cheaper than acetylene today so that factors in as well.

I love seeing the pics and hearing the discussion of the rebuild. My grandpa owns a 590D that is going to need some of this same treatment. Our bucket is solid, but there is quite a bit of slop in the stick, and it needs undercarriage work in a bad way. It had 13,000 hours when we got it so the best hours are long gone, but we don't use it a lot, just a little bit here and there throughout the year. Someday she'll get some good love too.

I got those tracks from my local Deere dealer for pretty cheap. It is really the easiest and least expensive gratification on an old hoe.

The boss wanted me to change hoses, more of a gut thing than logic. I did the 4 boom hoist hoses as they were original and stiff and easy to do, then I picked the 5 nastiest looking ones at the boom base and replaced with OEM's for about 1500.

Love the "talking to myself"!
I need to do 2 similar projects on my R130 LC3, keep the pictures coming. My bucket needs attention, new wear plates, fix a hole in the bottom and new adapters/cutting edge. I also need new pins and bushings. Its a farm machine so i keep putting it off.

Looking good. Wish I had welding skills.

I am getting ready to tackle pulling the boom away from the carbody and looking for advice.
The machine is all stretched out, thumb cylinder is locked off with the hoe pack valves so no stored energy there. I put the 4' bucket on for stability.
I was thinking, pull the top cylinder pin out and lower the boom cylinders one at a time as I remove that pin, then disconnect the hoses and block off lines, and pull the lower pins. The hoses block the lower pins so this looks like the right order.
Then I will weld on some channel in front of the boom base, so I can rest it on there and use a porta-power or whatever for some adjustment. I have a 5000 pound forklift to pick on that end of the boom, and I can borrow a guy but mostly working alone.
Slide hammer the pin out, block off the rest of the lines, and crawl the machine back a few inches till I can see through the boom bore. The channel I will weld on will be plenty long enough for that.
There is plenty of channel to build a rest for the boom heel on the ground.
I have new bushings for cylinder bottom bores, new lower cylinder pins, new boom heel pin, bushings, seals.
If the house does not check out with the new pin, I will call the dealer for line boring. I will pick up the boom with the forklift and back the excavator away from it, and either load it up and take it to the dealer or spin it around and have the mechanic line bore it there.
The other end of the boom/stick is not bad. The bucket end is really bad, but I have yet to gather all the CWS bushings and pin and parts for that. That is another day.

Thoughts?

I got the first boom cylinder off, it has a seal leak so I'll be taking it down and getting at least that fixed.
The car body bore looks questionable to ok.
I can wiggle the new pin up and down slightly more than I can front to back.
The old pin was seriously grooved and trashed and it looks like metallurgy might have won the day there.
If I have to line bore The boom locations, I'll probably just have them do those bosses too for the boom cylinders but if it was just this, I'd probably leave it alone with just new pin and bushing.

I have the lines all capped off and plugged. Hopefully the former operator will stop by and help me with pulling the pin tomorrow.
I made a rookie mistake, and forgot to bleed off the tank pressure. The return line from the hoe pack schooled me on that one. The tank pressure kept sending me oil down that line even with the line raised, so I put it back on and bled off the residual pressure. It was just the oil in the belly of the line but I knew better.

So what are you using this 120 for? I have been running a mini and skid steer for a while now, and am starting to upgrade to bigger jobs where I end up renting a larger hoe. I have been looking at the Deere 120s and 130s and 135s as my big thing is mobilization with a tandem dump truck and a tandem tag along. How much weight are you putting on your hitch when it comes to scale? Do you feel like having something 315 sized sometimes even though you would need a lowboy or tri axle? Thanks
Keith

The employer has had this machine since 2000 I believe, before my time. They are a commercial plumbing contractor. When I need it, I am digging for grease interceptors and larger CB's, or harder ground or larger trenches. I mobilize it onto any job I think it will help me get done better than the 35 mini.
Washington state follows the federal axle laws. That is 34,000 on any two axles. My 20 ton tandem tilt trailer is pegged right at 34,000 and I put about 6000 on the pintle hitch. It is legal and quite driveable. The only time it is a pain is on steep city streets.
I could not legally haul a 130+ class machine on two axles. I also do not want to spend the $$ pn a 3 axle trailer and this two axle is quite sporty and maneuverable.
I can get it all done with the 120, and if i wanted to rent bigger I would not mess around, and get at least a 200 class delivered as needed. It has not come up yet.