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

[skyking1]

Here's a tip for you, not a pro tip as I am an amateur.
When the boom hoses are out of the way, you have the best access to the well of gunk that excavators have around the swivel, swing gear, and valve body. This machine had 24 years of accumulated pine cones and needles and grease and oil and gunk. It was about 1.5" deep and caked pretty good. Pressure washing it out of there is pretty difficult and beyond messy.
I got in there and scooped it all out, scraped it and vacuumed it out. Then I cracked all the 6 lines and those two bolts on the swivel assembly, and tightened them back up to my personal specification.
Some of them were crazy tight and required two wrenching or hammering. it was easy to do through this hole.
I did that because I am ( hopefully ) dropping that swivel out when I do the Rotec bearing, and I will be standing on my head and getting at it over top of the boom. That is PITA enough with them pre-loosened. I hosed it down with some brakleen so there are no gobs of junk ready to contaminate the hydraulic system.

 

[Don.S]

Nothing failed it just had that much loose. We did not weld anything we over sized everything. My boss said he has spent far to many hours in a previous life welding up bores to do it to his own machines. The original was just a manual wedge quick attach and we made it hydraulic if you want i can take a few photos of it for you. It works great.

 

[DGODGR]

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

My 2003 315clc weighed in at 39,900# back when it was new. It's probably heavier than that now that it has 20 years of dust on it. The long undercarriage, reach boom, long stick, coupler, and thumb all add weight to move it beyond 15 metric tons. It also had a 36" CAT severe duty bucket when weighed. A 20 ton tandem should be able to haul 40k# of payload along federal guidelines. 34,000# is what was allowed in CA on tandems but I thought that 36k was federal. I don't recall where AZ is at on tandem weights. I bought a 25t tri-axle so that I could up size someday and not have to also invest in a new trailer. This didn't work out to be such a swell idea. When I first bought the 25t trailer I was thinking that I would "snowbird" back to CA in the winter. New Mexico only allowed 36k on the tridem and CA didn't even recognize the tridem so the most weight I could have (combined on the three axles) was 34k. The only way that I could make that happen was to drive the 315 all the way forward until the grousers made contact with the head-rail. Despite the trailer MFR telling me that I could put that much weight on the pintle, I just wasn't comfortable enough to do it. That experiment confirmed for em that tri-axles don't make sense in some states. Because of the lighter weight of the trailer (My tri-axle weighs 11k# vs ?? for a tandem) it would be easier to haul that much payload with a tandem. The other reason that the tri-axle didn't go quite as planned is that 20t excavators keep getting heavier. I now have (2) "20t class" machines. Both of them (a '17 Deere 245G, and a '21 CAT 325 NG) are much heavier than 50k# (60k#, and 64k# respectively). Therefore I must use a lowbed service to be legal when transporting. On the positive side, I do use the 25t trailer to move both of the big machines, but only within the subdivision that do most of my work in, and I keep it around 10mph.

 

[Keith Merrell]

My 2003 315clc weighed in at 39,900# back when it was new. It's probably heavier than that now that it has 20 years of dust on it. The long undercarriage, reach boom, long stick, coupler, and thumb all add weight to move it beyond 15 metric tons. It also had a 36" CAT severe duty bucket when weighed. A 20 ton tandem should be able to haul 40k# of payload along federal guidelines. 34,000# is what was allowed in CA on tandems but I thought that 36k was federal. I don't recall where AZ is at on tandem weights. I bought a 25t tri-axle so that I could up size someday and not have to also invest in a new trailer. This didn't work out to be such a swell idea. When I first bought the 25t trailer I was thinking that I would "snowbird" back to CA in the winter. New Mexico only allowed 36k on the tridem and CA didn't even recognize the tridem so the most weight I could have (combined on the three axles) was 34k. The only way that I could make that happen was to drive the 315 all the way forward until the grousers made contact with the head-rail. Despite the trailer MFR telling me that I could put that much weight on the pintle, I just wasn't comfortable enough to do it. That experiment confirmed for em that tri-axles don't make sense in some states. Because of the lighter weight of the trailer (My tri-axle weighs 11k# vs ?? for a tandem) it would be easier to haul that much payload with a tandem. The other reason that the tri-axle didn't go quite as planned is that 20t excavators keep getting heavier. I now have (2) "20t class" machines. Both of them (a '17 Deere 245G, and a '21 CAT 325 NG) are much heavier than 50k# (60k#, and 64k# respectively). Therefore I must use a lowbed service to be legal when transporting. On the positive side, I do use the 25t trailer to move both of the big machines, but only within the subdivision that do most of my work in, and I keep it around 10mph.

Thanks for all the good info. I appreciate it. I've looked into it and AZ is 34k on tandems. I wish I could rent some of the machines I was interested in buying but they are not available in this crazy market. I think AZ is 42k on a tridem but I would have to double check.

 

[skyking1]

Nothing failed it just had that much loose. We did not weld anything we over sized everything. My boss said he has spent far to many hours in a previous life welding up bores to do it to his own machines. The original was just a manual wedge quick attach and we made it hydraulic if you want i can take a few photos of it for you. It works great. View attachment 259204 View attachment 259205 View attachment 259206

Yes Don I would like to see those details. I get the idea from the one picture. I am surprised it holds well enough.

 

[skyking1]

I ran into a roadblock on getting the new Rotec bearing. The Ebay seller won't sell it to me unless I can verify fitment by counting teeth, etc. In other words he does not know what he is selling or doing. That's a bummer!
Sure, I'll just jack this thing up and count the bolt holes and teeth for you, no problem. Only about a full day of labor one way. No problem.

 

[John C.]

What do they cost from an aftermarket dealer? I've always had issues with people on Ebay.

 

[skyking1]

About double. Ironic thing is it's probably the same part from the same machine shop.

 

[skyking1]

OK the game is afoot! I have a rotec bearing on a pallet waiting for me to have time to install it. I have a job to do starting tomorrow so it will have to wait till late next week or so.

 

[skyking1]

All righty I'm back at the rotec job
Or have a port-a-power ordered, I'm breaking loose the bolts and capping off the lines to the swivel today. I'll try the vacuum cleaner trick.

 

[skyking1]

shop vac did wonders. The one case drain line would have poured oil instead not even a drop. It was a JIC #8 that's a big leak. I did not have the cap/plug for it so I wedged it up high and went for proper plugs where I did not have them. It is all broke loose and ready for me to take out the (4) bottom bolts and lower it down. I looked it over and will make a wooden custom block so I can jack it down with all the lines on it, with a floor jack. It only has to lower down 7" or so, and the lines are set up proper for that. I can screw a couple of 2x4 across the hole to hold it secure when it is down.
my 36" *Dunnage* is too tall, so I flopped it on the side. Now it is a perfect 32".
I have new nylon straps to wrap around one of the boom cylinders to act as a safety on that end. The parts runner will pick up the 50t porta-power for me and it is coming apart tomorrow.

 

[skyking1]

the bolts are all broke loose, but so is the wrencher. I am going to try a back brace today.

 

[John C.]

That job is hard on the shoulders and back when things go right. Be careful!

 

[skyking1]

Today the swivel took me to school. It was the perfect case of " do what you originally planned" instead of " let's try this shortcut"
I had such a good go with capping all the lines at the top of the swivel and I thought I could keep the lines on it and lower it down. First problem was the side case drain on the one side and some small return on the other, that got hooked up on the rubber seal. I jacked it back up, pulled those and then pulled the seal boot off the swivel. I plugged those holes with regular pipe plugs because that was some nasty stuff I was going to have to drag it through.
Then I tried lowering the swivel down. NO GO!
There is an extension on the top of the swivel for the torque plate, and to get it through the carbody you need to rotate the swivel assembly 90 degrees. You'd think that was easy enough, but that swivel is really tight and not something I could turn by hand. Looking back I might have turned it about halfway with the torque bar, but then I would run into the swing housing.
I just got the right plugs and took the lines off and capped them, like I had originally planned. In the meantime I got rained on by that combo of old black grease and water that accumulates over 24 years.

My first maneuver I managed to drag the house an inch towards the bucket side. Not a great start.
Then I got the porta power going and slowly got clearance under the gear. The only one I could get has a 1" stroke so it was slow going.
The 32" high concrete block was very handy.


I lifted the front up and set it on 3" of channel till I can get back to it. I will take it up another half and it will be even with the back, when I go to drag out the carbody.


New slewing bearing is ready to unwrap and install. I won't get back till Thursday as I have a dig with the mini tomorrow.

 

[skyking1]

I looked over the job some more. When I get it airborne and wrap my nylon lifting strap around the cylinder for safety, I will pull the sun gears and drag it out and horse it a little sideways to fix my mis step today. When I have just enough room to work on the bearing comfortably, the idler and ~2' of track will be under the frame below the cab, so I can crib to the idler with some big blocks I have for additional safety. I need to get under the house and clean up the bottom of it before I can set it back down.

 

[skyking1]

OK, several of my pictures didn't. I lifted up the machine. i took off the final drive covers, removed the sun gears, pulled the carbody and track assembly about 8' out from under the machine, using the other excavator.
I blocked up the machine on the end of the track and a vertical 4x6 . Crawled under and cleaned off all the gunk and grease off the bottom by that drive gear in the pictures above.
There was 5 gallons of greasy gunk the consistency of cake batter in the tub inside and below the rotec vbearing.
I sacrificed a shop vac to the excavator gods and sucked all that gunk up.
@John C. was available and was gracious to come over and help me with the heavy stuff. I had broken loose the 36 M16 bolts that hold the gear to the carbody, and we got it off, cleaned up, installed the new bearing, shoved the tracks and carbody back under the excavator, lined it up and lowered it down in about 3 hours. That included torquing 66 bolts to 200~250 pounds.
So we went from this:


To this!



John, I can't thank you enough. I would have been a long time with a lot of frustration getting it lined up by myself. Getting all those bolts in and torqued was a huge task after that.
On a side note the 35 mini moved that ~12,000 pound carbody assembly sideways with ease. The two of us got it lined up quickly.

 

[skyking1]

just sitting there at idle, I can tell how much of a difference the pins, bushings, line bores and slewing bearing have made. It is like a new machine in pitch stability. I'm also sitting on fresh tracks. This is going to make work faster and more pleasurable, more accurate.

 

[Gary Layton]

Great descriptions and updates on your work. Thanks for the time you spend documenting this.

 

[skyking1]

Thanks. Like I said, several pictures I thought I took are missing, the ones with the carbody pulled out and the tub of gunk, etc.
I have some apitong cutoffs from the trailer deck replacement, and I wedged those on top of the track over the idler and under the cab frame for security.

 

[skyking1]

we did the chain through the hole trick. One of the plumbers is a pretty good operator, and another plumber guided it from above while I got the bolts in it.

It gets these 8 lines below

and 6 above. I had to clock it 90 to get the torque flange through the hole.

I had not labeled the top hoses so off to the online parts manual to figure that out. There's a rubber boot that snaps over the yellow casting and seals around the swivel. That is the torque bar that holds the top of the swivel in relation to the house. It is surprisingly stiff to turn, i could not budge it but that is normal. You want them tight, according to John C.
Note the pipe plugs in the sides. Those had O-ringed JIC adapters that I had to remove to get the boot off, and I plugged the holes before I dropped the swivel down through that infernal gunk. I kept plugs and caps on everything. I probably did not lose more than a cup or two of oil.