Hey gang. I have a Hitachi EX120-2 with a loose boom to frame pin and bushings. I’m having a tough time finding a new pin and bushings or at least a company to sell me a set. I’ve tried to look up the parts numbers in my parts catalog but they don’t pop anywhere on the web. Even if I knew the proper sizes I can get some made.... mine are too worn. Any how... any help is appreciated. Thanks, Joe
Have you tried John Deere dealer
Yes. John Deere dealer is my only option for Hitachi parts Unless I can find aftermarket like I did for rebuilding the bucket end. JD said sorry that boom pin and bushings are no longer available. I don’t know what JD machine is same as My EX120-2. So maybe that’s a start. I could even buy the pin and bushings for the boom from a newer Hitachi but without confirmation on part number and size I’m just guessing. That can be costly.
So I’ve dug a bit deeper. Looking on line I found the JD 490 is close to being the same but 490D or 490E is the question. I don’t think Hitachi would redesign a boom pin for the same machine every 4 years for the new model year (120-2 vs 120-3) and I read multiple places that the ex 120-3 is the same as the 490D. Parts are too expensive to play Russian roulette. Can anyone help me figure out if I should be ordering 490D or 490E components? My machine is a EX120-2 I cannot find the Hitachi parts for my machine easily. I keep being told no longer available. I’d go custom made but trying to find a shop without measurements is impossible and my pin is shot and my bushings are like foil. Thanks, Joe
There is a machinist in extreme southern mass I'd use. He'll make parts to fit exactly. A touch grumpy, you'll like him. I think I can get contact information if you need.
Willie B- I'd appreciate that. I believe at this point that may be my best course of action. I'm in that neck of the woods all the time. If you can send me his info on PM. Not many guys doing that anymore. I can get pins machines to what ever specs I can imagine but making the bushings is the tough part. Thank you, Joe
STATUS UPDATE 03/13/2020: Hitachi EX120-2 Boom to main body pin and bushings. I took my original Hitachi parts booklet for my EX-120-2 and compared it to the parts booklet on line for the John Deere 490E. They look to be the same dang drawing even down to the numbering system. I Verified some of the parts (bushings and seals for the boom to main body joint ) with the John Deere dealer. They were diffrent numbers because part numbers superseded according to JD parts dealer. John Deere also did not want to be liable at the first phone call to "guess" that the 490E and the later 120-2 and 120-3 machines are practically the same minus engines ( John Deere uses a JD engine and Hitachi uses a Isuzu engine) plus a few smaller items like paint, seats, accessories and badges. LOL. I do not have serial number cut off details BUT the parts manager AFTER I gave them the Hitachi numbers, confirmed they supersede to the present John Deere numbers. Again, if they order the parts they cannot return them I was told. If I give them the numbers they can verify BEFORE I order them... Funny how that works. At the time of this post the parts were like 3 days away. I ordered them and will update with if they actually fit when I have a moment to rebuild this boom. For anyone later in life looking for these numbers they are as follows: PN 3081004 Boom to main body pin Superseded AT154896 and 3050671 As of today $616e PN 3051399 Bushing Boom to main body Superseeded AT154116 and 3051399 As of today $141e PN TH104472 Seal for Boom to main body Superseeded 4084578 As of today $27e
I tracked down his contact information. I can't seem to send a private message. Get me your Email, I'll send it.
How did you do the bushing job, full disassembly or leave it in and jack it up in place?
Sorry Skyking1 - we have not actually performed the work yet. I’ve been really busy with work personally. We are expecting to use another machine like a truck tow truck to take pressure off the boom and remove the main pin and cylinder pin. Then remove and cap the hydraulics and set the boom so the bushing area is at working height using an A-frame type cradle we built at my shop. Something large enough to keep the boom from falling over and maintain height. Perform the work and call the tow truck back in and reassemble. We’ve had extremely warm weather here in Connecticut so I’ve been taking advantage of the outdoor working. Joe
Thank you for getting back to your thread . I am going to try the other route, stabilizing and then lifting the boom up with the boom cylinders just high enough to scarf out the bushings and pull in new ones using an Enerpac hollow cylinder and power pack. https://www.enerpac.com/en-us/hollow-plunger-cylinders/aluminum-hollow-plunger-cylinder/RARH6010 I can machine up a tool that fits inside the bushing a bit, and is slightly smaller than the OD of the bushing. How long are the bushings? Looking to get an idea of how much room I have between cab and boom for tooling.
Sorry for not getting back to you sooner. The bushings are like 4” long. Mine was worn thru the bushing and egged out the bores. I need to do a full- machine round, weld up smaller and machine out to proper bore size for bushings. The pin bores as well. It’s really sad how some previous owners are allergic to grease. I can get an exact measurement when I’m back to my shop if that is needed let me know.
thank you so much. I fear that my situation is the same. I had hoped to re-bush and go, but it sounds like I will need a line bore too. Sometimes I get too optimistic
Did them bushes on a 16 tonner by fitting a wide bucket ,raising the boom with its own cylinders ,welding a heavy walled I beam on its side on top of the pin bosses on the carbody and lowering the boom into the I beam . It was just a pin and bush change(no line boring needed) and the rest of the machine was fairly tight . I wouldnt chance it on a well worn machine .
Thanks Volvo that is a great suggestion. I had all sorts of Rube Goldberg ideas to secure it and that sounds pretty simple.
Like I said above Skyking ,the rest of my machine was pretty tight .Just the boom pin and bushes started gauling one day and even though greased regularly since new things went down hill in one working day . I considered doing it on a 20 tonner that I must bore but as the rest of the machine is also well worn ,I think I will take it apart to be on the safe side .Be careful ,whatever way you do it .
were you able to freeze in the bushings on the 15 ton machine, or did you need to pull them in with a press? Yes, safety above all. I may pull it apart and evaluate it after I get my bushings and pin here. I have a supply of 2x6 channel and 6mm plate to build any sort of support tooling, and am confident I can do that without risk. I have a 4' clean up bucket to fit on it, and the 35 mini and a 5K forklift at my disposal. If I don't like the way it is going I can rent a boom truck as well and transition to full disassembly.
I dont have a hollow ram or access to liquid N . I put the bushes and drivers/dollies into the domestic freezer over night and pulled them in with threaded bar .
Thanks very much for that! We have an account at the welding supply and they'll give me liquid nitrogen in a rental dewar for $80 usd. I figure that's a bargain.
Sounds good and should make very light work of it
Dry ice is easier to work with. Most welding gas supply stores sell it. Bring a small cooler and welding gloves. That stuff is nothing to mess with. Freezer burn on bare skin in 0.0001 sec. lol!
I have a few years of experience working with liquid nitrogen, building landing gear parts for Boeing and others. It gets about 200 degrees colder than dry ice, and I am comfortable working with it.
That’s cool! I’ve never played with Nitrogen in liquid form. Having done pins and bushings for part of my living for almost 25 years now on heavy equipment the freezer works just fine. I always pop the bushings in the freezer for 24 hrs and pre heat the bore with a small torch to the point where you can no longer touch it with a light glove. Not blue or discolor. Just hot. Then the bushings drop right in. .002” interference fit is typically what I’ve encountered. Sadly once the bore has been machined, bored and remachined I am not sure of the expanded rate changes. But it always has worked. Lol! Send so pictures of the liquid stuff at work. I’d be interested in seeing that!
This pin fell in under its own weight after being soaked overnight in liquid cold @ -320F and once everything was nicely lined up. To remove it probably needs something comfortably excess of 100 tons. Big pins like this are easier, they retain the cold. The smaller the pin diameter the less time you have to work with during the installation before it warms up. Provided the stuff is readily available in your area I'd say that once you've tried it you would never consider doing pins or bushes any other way.
Thanks Nige for that example. 1) pins only shrink so much. There is a mathematical formula for it, so big pin = big shrink 2) bushings are really awesome, as they are a ring of thin metal and they shrink significantly more than a solid pin. When I was doing it we had aluminum tools to drive them in and set them, because they were not very long and might push out as they warmed up. Long bushings don't do this, like the ones in our gear. You would pull them off the wire, slap them in with your gloved hand, and double back in a few moments with the driver to insure they remained seated. The parts were titanium scissors on the main gear of the B747 as shown in this picture, and also the nose scissor linkage. This pair of parts is what keeps the wheels from turning sideways on the strut.