I spoke with Perry on the phone earlier today, and he suggested I ask the forum: I recently (yesterday) purchased a Bobcat 853. The engine and hydraulics work great, BUT it has a (or several, in my opinion) big problem which occurred before I bought it: The left rear axle seal went out. Then the bearing(s) went out. I believe all the fluid is gone. The seal and bearing are completely chewed up. The driveshaft has been running on the upper edge of the axle, causing the axle to bulge. The driveshaft is pretty chewed up out next to the wheel hub. To further aggravate this situation, the lip that runs around the wheel hub that holds the studs on (that holds the wheel on) is COMPLETELY worn down--I'd guess about an inch of meat that encircled the axle is gone from the hub, and I didn't measure how much axle meat is gone. Other than that, I think the machine is in great shape. It's got 3655 hours on it. I was thinking about taking it apart and rebuilding it. Here are my questions: Should I just scrap or trade the thing, or should I rebuild it? If I trade/scrap it, then it's somebody else's problem, but if I choose to rebuild it, I'm gonna need some manuals. Are there any parts diagrams available on the internet for my 853? Also, do I have to take the machine apart from the top? It looks like the belly pans don't come off, so that's what I am thinking has to be done in order to get at the drivetrain. I don't have any manuals yet, but I have to figure out how to detach the drive axle from the inside. If I rebuild it, I was thinking about putting in a new axle shaft, bearings and seals. For the axle itself, I was thinking about cutting the old axle back to where it is solid, welding a new piece of pipe (axle) in with flush edges, and then welding another solid sleeve over the top of the entire piece of axle that sticks out from the side of the frame, and then butt-welding that sleeve to the frame of the machine. That's the only thing I could think out to make sure the strength is there so my welds don't break with all the wear-and-tear on the axle. Any thots? Thanks.
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skidsteer.ca
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What you need to do to tear it apart is pretty much described in this thread.
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=13406
Weather its worth it or not depends on where you think you will be pricewise at the end.
A 853 can be had for in the 9 to 11 US range. Manuals are available on ebay from "maxxwedge" or at the dealers. They have a new one out for the 773 that is $82 instead of $55 but has great detail compared to the one I bought 4 years ago. Not sure if they updated the 853 one as it was only mad a few years, but I'd ask b4 buying one at the dealer.
My first concern would be to lift the cab and open the chaincase and see how everything else looks in there. Depending on what failed first you may need to change more then one set of bearings. The axels are not supposed to have more then about .010" end play. They use a common tappered bearing and cone. There is no threaded adjustment, they are either ok or need replaced.
Which also means if you are replacing the end of the axel tube inboard from where the outer bearing sits, then you will need to be quite precise. You may need to take another axel out to get measurements.
As far as welding it, I think sleeving the outside after may be over kill, but likely worth it. Had the tube broke on the inside end at the chaincase there would be quite a lever effect working on the weld that your not going to see on the outboard end.
I wonder if the axel tube is available as a part? Or removed from a wreck. It would be easier to put a whole new tube in and you would be back to straight, exact lengths for bearing space and strength.
Also the 853 are a rugged and reliable old machine, but the hydros drives are not as user friendly as the 700 series. The sticks don't have the feel in them and green horns have a harder time controling them. Even with ample seat time I still find it harder to do fine work with it then any of my other loaders.
I'm sure this can be saved, but it's not a job for the faint of heart.
Ken
http://www.skidsteerforum.com/DesktopDefault.aspx?tabid=54&frmView=ShowPost&PostID=13406
Weather its worth it or not depends on where you think you will be pricewise at the end.
A 853 can be had for in the 9 to 11 US range. Manuals are available on ebay from "maxxwedge" or at the dealers. They have a new one out for the 773 that is $82 instead of $55 but has great detail compared to the one I bought 4 years ago. Not sure if they updated the 853 one as it was only mad a few years, but I'd ask b4 buying one at the dealer.
My first concern would be to lift the cab and open the chaincase and see how everything else looks in there. Depending on what failed first you may need to change more then one set of bearings. The axels are not supposed to have more then about .010" end play. They use a common tappered bearing and cone. There is no threaded adjustment, they are either ok or need replaced.
Which also means if you are replacing the end of the axel tube inboard from where the outer bearing sits, then you will need to be quite precise. You may need to take another axel out to get measurements.
As far as welding it, I think sleeving the outside after may be over kill, but likely worth it. Had the tube broke on the inside end at the chaincase there would be quite a lever effect working on the weld that your not going to see on the outboard end.
I wonder if the axel tube is available as a part? Or removed from a wreck. It would be easier to put a whole new tube in and you would be back to straight, exact lengths for bearing space and strength.
Also the 853 are a rugged and reliable old machine, but the hydros drives are not as user friendly as the 700 series. The sticks don't have the feel in them and green horns have a harder time controling them. Even with ample seat time I still find it harder to do fine work with it then any of my other loaders.
I'm sure this can be saved, but it's not a job for the faint of heart.
Ken
Anything can be fixed!
As for adjustment for wear, this is simply done by the washer at the end of the sprocket. You can buy special washers with a recess at .005 .010 etc to take up any end play. If you have a lathe you can do this your self. I wouldn't cut the axle tube, if you do, your lengths will be all wrong as you need it so when the axle is in there you have no end play, depending on just how bad the damage is you may be able to get someone to line bore the end a bit to get it back to round. As for the axle, i would machine the worn section down, press a 4140 sleeve on it and machine it down to size.
Can you take some pictures? it would give us a bit more of an idea on the damage you have.
If it was me, i'd try to fix it, but i'm a sucker for punnishment
If one set of bearings is gone, honestly i'd replace the lot.
Ken, Thanks for the quick reply. I am mechanically proficient, but I've never tackled a job quite like this one before. I've got a little bit of time and money in this machine right now, and I've seen similar machines for 7 and up on the internet (I don't have that much in it), so I think it might be worth it for me to fix if there's no major damage in the chaincase like you mentioned. I'm going to call the dealer tomorrow and ask them about the parts, and I'm also going to ask them about using this machine for trade-in on a different machine if the cost of the parts is prohibitive. Thanks for the info on maxxwedge--I'll definitely take a look there for a manual or two if I decide to do this job myself. Having the service manual is the only way to go as far as I'm concerned as it has proven valuable on other jobs I've done. I'll let you know once I make a decision. If I do fix it myself, it should be a good starter project for a Bobcat rookie like me. I'll take pictures if I do the work, and I'll post them on here so you can see the extent of the damage and then what I did to fix it. I'm sure I'll have more questions later. Thanks again. Chris
mllud
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Try this salvage yard. They have bobcats. http://www.wengers.com/ . I have done business with them. They will be able to help you beller if you have a part number. Mike
Thanks, Mike. I have sent them an email. They didn't have parts for an 853 listed, but maybe they have something they haven't posted, or maybe they can refer me somewhere else. I'm also wondering if multiple machines use the same size axles and shafts? Any ideas on that? I assume that the machines in the same horsepower range use the same size parts. That sure would streamline the assembly line... I'll let everybody know when and what I find out. I keep thinking there can't be that much to it, but I'm sure it will be a lengthy process, especially if I go cutting axles out and so-forth. Keep your fingers and toes crossed. Thanks. Chris
mllud
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Chris: Tazza or Ken may know what would or may interchange. Im not a bobcat owner, I have a N/H loader. They have a lot more part for Bobcat than anything. If you go own to the [Salvage] forum. Then go down the list of threads to the second one from the bottom there is a list of salvage yards. Wengers is the only one Ive dealt with.Good Luck. Mike
mllud
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Chris That is the [Salvage/Parts] Forum. And the thread that has the links is the one all the way down and is titled [Helpful Links].
skidsteer.ca
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The axels may cross with other 800 series. ie 863, 873, 883, but I think only a dealer could tell you. I know they have a larger axel tub and the hub is retained with 3 bolts instead of 1, so that rules out the 700 series.
Maybe Mark will pop in from Intermountain Bobcat.
Ken
I spoke with the dealer today. He guessed his repair costs to my 853 at $1000 USD, and I'm thinking "NO WAY", but maybe that's HIS cost, not mine. The parts guy looked up the axle tube itself, and it's part of the body on my machine, and it is not a part they have listed, so I either have to find a junked machine to take the whole tube off of, or I have to rebuild the axle tube that's on there now. Does anybody know which IM Bobcat Mark works at? I found 4 listings for IM last nite on the web. I'm having the salesman from Springfield Bobcat come out and look at my machine before I do anything more. He's got a 553 in his rental fleet right now that I may do some trading for. I know it's about 1/2 the size of my 853, but I could definitely haul it, and it would be more maneuverable in tight spaces. I guess I don't really care either way, as it seems all the machines are about the same price, altho trading would be a lot less work for me right now. Oh, and the parts guy said there's about 13 gallons of oil running in the axles and chainbox, so if I lost a lot of the oil, I do need to replace the bearings and seals in all areas. We'll see, I guess. Thanks again for the info and responses. Chris
skidsteer.ca
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Thanks. I'll email him.
