HAS ANYONE EVER HAD THE BOLTS THAT HOLD THE SWING MOTOR TO THE FRAME ON A 490E JOHN DEERE COME LOOSE.:beatsme
Marc, Welcome to HEF please do us a favour and refrain from posting in "ALL CAPS" as its considered yelling in nettiquette terms. Thanks
Maybe He was yelling after His gearbox came loose! No, seriously, I've not necessarily seen it on a 490E but on that size machine the swing gear box bolts need to be torqued to approx. 100 ft. lbs. Given that the boltheads are about 3 feet down makes for a hard time getting them to that torque, so an air wrench is often used and they don't always give the proper torque. Use a 3/4" torque wrench with several extensions and 2 people, or the ideal way is to either use a torque multiplier or a hydraulic torque wrench. You should also use blue Loctite on the threads.
I installed a new swing motor on my Hitachi and the torqued was even more than a 100, I can't remember what it was but it was alot. Dealer sent by fax a set specs. I do remember going to Sears that day and spending some bucks on two 3/4 extensions and spent $2000.00 for parts, this was last winter. I used blue Loctite also. Had to use a fork lift to pick motor out for repair.
Yes that does seem a little low but I grabbed my 490E manual and looked it up and the gearbox to frame bolt torque is listed as 91 ft. lbs. However, that may be a typo because the JD 120C manual lists it at 290 ft.lbs. which sounds about right.
Welcome to HEF marcmustang1! :drinkup
490 swing motor My 2 cents again. Make sure the gear box is not moving when you swing. I had this happen to me, it was the bearing bad. make sure no noise, etc. replace bolts, I would replace with a harden bolt, Im sure the orginial was harden. clean threads, blow out holes. use locktight. Torque to factory spec's. Check again in about 8hr of working time This is a trick I found out about a few years ago. I had some bolts in the swing gear that broke off, I saw no way, except to drill and tap, many hours of hard work. I contacted an old friend of mine and he came over and in about 3 hours, he had the bolts (8-3/4") replaced. I am pretty mechanical, but this impressed me, he took a 3/8" X 4" pipe nipple, put it in the hole on top of the broken bolt (about 2" down) he then took his stick welder and just welded the pipe to the bolt from the inside of the pipe, let it cool and screwed it out with his fingers. This may not impress many people, but it did me. I used it several times after that.
This is an old thread, but I just joined the site after a Google search turned this up. I am supposed to repair a 490 with this problem. The owner began having problems with the swing-motor mounting flange bolts backing out. Re-tightening got to be a frequent ordeal. Recently, enough of the bolts backed out enough that parts of the flange broke off. In short order, the remaining three bolts tore the threads out of the baseplate, and elongated the holes sideways in the direction it was swinging at the time of failure. The local Deere dealer, Pape Machinery in Tukwila, WA, went through the swing-motor and installed a new flange. Now we are trying to figure out how to avoid a repetition of the loose bolts. I picked up an M20X2.5 helicoil kit with eight 40mm-long coils. The first problem is putting coils in the three stripped holes. These are fairly round at the bottom, and oblong at the top. I'd like to partially weld up the elonmgated areas of the holes, followed by rough-dressing the beads with a rotary file to reasonable roundness. For the next step, I've made a plate that will hold the drillbit (13/16" IIRC) (for helicoiling) square with the baseplate, something I do not always do well "by eye." I can just C-clamp it in place for drilling. To work the helicoil tap, I have some long socket extension and a T-handle so that I can at least do this operation without hanging myself down in the hole. May I say, I really am NOT looking forward to any part of this job!! At this point my question is: Is the base-plate, that is, the plate to which the flange of the swing-motor bolts, made of a weldable steel or is it an iron casting? I'm mostly a welder, and don't know much about these machines. (I see a contributor with the internet handle "Excavator" who evidently knows a great deal about these things, and hope he will comment). Having helicoiled the three stripped holes, I wonder if I should drlll out and helicoil some or all of the remaining holes (total of ten, IIRC). I'm thinking that even though the threads still look good, maybe the bolts were backing out because the threads in the holes had gotten compressed and loose-fitting. I'll run a bolt into each by hand, and see if I can feel any obvious looseness. But even with all of the holes helicoiled, I'd be wary of the problem recurring. If you bash anything enough, it will eventually fail. So one idea I have is to try to lock the swing-motor into position relative to the side-loads, so that the bolts and their clamping force on the flange-to-baseplate interface don't have to do all of the work when the swing-motor tries to twist one way or other. If you look at the mounting flange on the swing-motor, the periphery is not round but has several deep indentations, and those are what I want to use to take some of the side-loading. What I plan is to set the swing-motor atop a thick steel plate and scribe a line around the flange. I'd then flame-cut and finish-grind the plate to that scribe-line. With the swing-motor then bolted in place, I'd slip my new, close-fitting retaining ring over the top of the swing-motor and down over the flange, and tack-weld it in place. I'd pull out the swing motor and dual-shield weld the ring to the baseplate (as best I can in such cramped quarters!). Then I can bolt and torque down the swing-motor and it might stay put for a while. I'd welcome any better ideas!!!!!!
I'm just the opposite of you, more a mechanic than a welder. The carbody would be steel, probably T1 and yes it is weldable. If there are more than 1 or 2 bolts broken I would be concerned about using helicoils as they also tend to work loose. You may be ok with 3. Personally I would clamp a small peice of brass or copper under each hole and then using a wirefeed welder, weld up each hole, re-drill and re-tap. Of couse, it helps to have all the nice tools for jobs like this, mag drills ect. Make sure the threads in all the holes are good, then install the swing motor and use a good Loctite and torque the bolts. I think trying to weld to the swing motor will bring more grief than you already have. Just my 2 cents worth, looks like I'm just about 2 hours north of you. Let me know how it goes and please feel free to ask more questions.
I have a question that I don't know the answer; does the underneath of the swing gearbox have a shoulder that fits snuggly into the mounting base ring on the carbody on these things? I agree about the Heli-coils, I'm not so sure they can handle the stress that would be put on them by such a large machine. As for welding, re-drilling, then re-tapping the holes, I like that idea better. Would it be possible to remove all the bolts, then turn the gearbox to the area inbetween the existing bad holes, then just drill and tap new holes. Just an idea.
I never considered that, there would probably be a problem with a few hoses not fitting. The hoses to the control valve are pretty tight already. I might also be concerned about the distance between holes. How much would you weaken the car body by drilling another hole between each one? When I repair a machine, I really like it be as close to original condition as is possible.
I'm thinking you got more problems than just the bolts coming loose. In my experience the Rotec bearing is usually bad and the resulting up and down and back and forth movement is what causes the swing reducer bolts to come loose or breakoff. As I recall there should also be al least one and usually two dowels installed in the swing reducer base plate going into the house. The dowels are what keep the swing reducer from trying to spin in the house plate and the bolts are supposed to only hold the flanges together. The other issue is the bottom of the house itself. I've seen several excavators with high hours have cracked weldments underneath. I would suggest that before you put the swing machinery back in that you do some very close inspection. Good Luck!
Just got back. My laptop suffered the Blue Screen of Death, so I use the library's computer, stand in line, one hour limit. I'm not going to weld directly to the swingmotor at all. The idea is to slip a close-fitting ring (or sections of a ring) around the flange, and weld that ring directly to the baseplate. The swingmotor could be lifted out at any time afterwards. The ring is intended to provide a stop against all but very small amounts of twisting of the swingmotor relative to the baseplate. I had thought of doweling the flange to the baseplate, which would prevent any twisting at all, if the dowels are big (3/4" at least) and very accurately drilled and reamed for the right fit. Can an old fat man do that kind of close work hanging upside down in a oil-soaked hole on a hot day, working at the limits of his reach? Well, possibly, if he builds some good guide-plates, but I just thought the ring idea would be easier and maybe good enough. With the ring located in place, I can tack it, pull the swingmotor back out of the way, and wire-feed weld it by feel, since I'm not going to get a view of the puddle very often. I don't know what model 490 this is, but it had no dowels. Boy, I sure hope the baseplate is NOT T-1. I'll have to try to find that out from JD if nobody here knows for sure. T-1 of that thickness wants a good preheat, which if nothing else will add to the unpleasentness of the project. I really need to get a parts blow-up with the correct terminology so I can explain myself better. "Rotec bearing" and "house plate" are unknown to me, John. My one alloted hour of computer time won't let me do much searching, so I'll get a zerox from the dealer. The big ring gear (that the swingmotor pinion gear acts upon) is currently almost immersed in gear oil. Is there a drain for that, or do I need to suck it out with a shop-vac? Is it a sump, in other words, is oil being drawn out and pumped to other locations? If it is not then maybe the drillings and shavings that get in there will just settle to the bottom and not hurt anything. The other issue of the gallons of lube is the fire hazard if I weld. This is pretty heavy oil that shouldn't have easily-ignited vapors above it except maybe on a really hot day . . . or if I have to preheat a inch-and-a-half thick plate of T-1!!! Besides that pool of oil, the entire area is full of oil-soaked twigs, dirt, etc.. The owner is a small operator who has no steam-cleaner, just a power-washer, which I don't like around machinery, but it's all we have. Anybody every set one of these babies on fire with welding sparks? I'd have a fire-bottle at-hand (and a phone), but even so . . . . He is a pal, and won't sue or hold me responsible, but his insurer would.
I'm sorry. I'm used to sites which have an edit icon so I can clean up my post right after I put it up. I have to remember to edit first. Putting out unedited copy when asking for help seems disrespectful and sloppy, and now I'm guilty. I will do better:Banghead
I read this thread with interest (and joy that I'm not the one that has to attempt this repair.) Here's another idea for helping secure the swing motor. Use the helicoils as planned in the three holes. Install the motor back in its original position. Then drill some extra holes down through both the cast flange around the edge of the swing motor and through the steel mounting surface underneath. Drill the holes through the swing motor flange slightly larger than through the steel underneath. Then tap the steel base metal and install extra bolts. I may be missing something. And I don't know if there room to do this, but just another idea.
Not a problem Smitty, you've made your third post and will see more privileges open up to you, including being able to edit a post. We give you one hour to make corrections, then they're permanent record.
Hey Smitty, bummer about your laptop. Mine crashed back in December and I was about to flip out without it. Rotec bearing: common name for slew ring bearing, the big ring bearing that the machine rotates on. And you should take the time to examine the slew ring bearing for excessive wear. Like John said, it could be the cause of your problem. Fully extend the arm and bucket of the machine and boom down until bucket is close to the ground. This should load the slew ring forward. Have your operator gently place bucket to ground and push down with boom, this will relieve the forward load on the bearing and make it rock to the back, see how much movement there is while doing this. There is a spec for this, just don't know what it is. A small amount of movement of the bearing is acceptable. If it moves, say, 1/4 - 1/2 inch, I'd say your pushin' it. House plate: we commonly call the upper structure of an excavator or crane "the house". The house plate is the large/thick plate that the whole upper structure is mounted on and the slew ring bearing bolts to the bottom of it. Gear oil in slew ring sump: this would have come from past failure of rotation gearbox lower seal failure. You stated that the local Deere shop went through the gearbox so that issue would be resolved. And yes, there should be a drain. Climb under the machine and look up into the center underneath the house plate. You should find a small oval shaped plate with 2 bolts securing it. This plate covers a hole in the house plate that will drain off fluid/water that's in there. A thorough rinse with water should remove enough flammables that would hinder welding. Put the plate back on, add a good layer of water in there and you should be good to go. The thing that would concern me more would be all the oil soaked twigs and debris on top. Yeah, that stuff could easily light from welding. Going to shut up now...I'm chewing up your 1 hour.
Back again, Slew-ring bearing, dang, another thing to deal with! But I needed to know, and appreciate your telling me. It being Monday, I was able to phone and talk to a mechanic at the dealership. First, he says the base is made of an easily-weldable steel, not T-1. Second, as you said, the "gear oil" I saw was massive leakage through the swing motor mixing with the GREASE that is supposed to be on the ring gear, and it must be drained. He says if I pull the boom back high and tight to the cab, I should be able to rotate the cab by hand, which I have to do as I slather new grease about an inch thick on the ring gear, a section at a time. My supposed "gear oil" was a rather light brown, probably indicating that a fair amount of water had got into it as well. Once I get all the glop drained, the area cleaned as best I can, the dings filed off the mating surfaces, heli-coils installed, and the gears re-greased, the mechanic says to apply silicone sealant to the mating surfaces before torquing down the swingmotor to keep water out. He says they don't use Loctite on the swingmotor attach-bolts on bigger machines since they are hard to get out as is, but that it might help with the bolts on our little 490. with nothing but spraycans of carb cleaner and Brakleen, it's going to be tough to get those threads clean enough for Loctite to work, but if the job was easy, they wouldn't have to find a dumb clod like me to tackle it.:Banghead He also says they have something they like better than Heli-coils, and by his description they sound like the Keen-serts which I've used in Boeing tooling shops. I wouldn't think these would necessarily work better than Heli-Coils, but am not about to argue with experience. Finally, he said that all of the bigger machines and newer 490s have a couple of dowels locating the swingmotor and taking the side-loads. So, I suppose I'll have to drain the base section (with the mounting flange) of the swingmotor and remove it so I can drill and ream for dowels. Atco, in checking the play in that slew-ring bearing, where do you take the measurement? And if it is unacceptably loose, I assume we have to get the dealer or somebody to lift the cab off the chassis so that the bearing can be replaced, right? On the whole, I'd rather be welding (or fishing). Better yet, I should have gone through law school, and been issued a big hose to siphon megabucks from the pockets of my fellow Americans:usa (Excuse the gratuitous op-ed comment; the Smith family aversion to lawyers is genetic, I think).
Here's a crude sketch (that everyone can make changes to as they see fit ) of where you want to check the slew ring for exessive movement as the bearing is loaded forward the back. There is an actual measurement "spec" for the machine, but for now, just a visual check of excessive movement is what we want to see. If you get noticable movement, then get the Deere spec and acurately measure to see if it's within tollerance. And yes, if it's bad, you would have to remove the house. John C could give you advice on that if needed, I'm pretty sure he's yanked a couple of them. View attachment slew ring measurement edited.bmp
Thanks, bud, you have been a great help.
Hey, you gotta thank John C...this'n was his idea.
Sorry Smitty, but like I said, more of a mechanic than welder. As far as hanging upside down to do this job, how about removing the fuel tank. It would give you a fair amount of room to get in there and they're very easy to remove.
ATCOEQUIP has the procedure exactly right and a great illustration as well. I use a dial indicator with a magnet mount set up on the carbody and the dial reading the bottom of the bearing piece that is attached to the house. New bearings generally run in the range of 0.030 to 0.040 inch up and down. Anything over 0.060 will be easily visible and when they get up around 0.100 you will usually see flakes of metal being washed out of the bearing when you grease it. It will usually be well over the 0.100 mark to actually damage the mounting for the swing reducer. Draining the grease and oil is also exactly as ATCOEQUIP has described. I usually use a very long extension on a ratchet to take one bolt out of the drain cover and let the other hand loose. The gasket will hold the cover tight usually and I use a long bar to pry it loose. You will probably need a big drain pan underneath to catch most of the crud. If the bearing is bad, it will be far easier to repair the swing reducer mount holes when the house is off the carbody. The other item is the expense. Right now a 490E is not worth much in the market and the replacement of a Rotec bearing for parts and labor will be as much as another machine might cost. Let us know what you find. Good Luck!
Talked it over with the owner last night. He agrees that the cost of repair could easily become uneconomic. So for now, he and his son are going to heli-coil the three bad holes themselves, pump out most of the oil and drain the rest, clean the threads and install the new bolts with Loctite, and see how it bears up. I don't hold out much hope for those guys doing a good job with the helicoils, but it's their machine. So it all turned out moot for me. Just as well; there are easier ways to make a buck. But I am greatly impressed by the quality of information the members of this site are willing to give a duffer like me!! I have a hydraulic mystery with my own pet Bobcat 630, and although I am determined to figure it out myself, if I end up absolutely stumped, I'll pay y'all another visit. Thanks a million:notworthy