Slewing ring (rotec) bearing replacement

[tctractors]

Coondog, I have not ever even worked on a CAT 375 excavator,but I have poked about on some fair sized O&K iron, but no matters?? I always blank off the pipes that go to the Rotary Coupling (C/Joint) from the valve block, this allows you to use the excavator hydraulics to lift the front up, I have never heard of anyone jacking this bit (Fservice might do it ???) so with the Pipes blanked of and the R/coupling possibly lowered into the carbody? and the swing box's pulled out your job would have been just a bit of Donky Work on the ring bolts, lots of sites in the U.K. would not allow this type of repair to be done,the excavator would have to be moved off site or done over the weekend without eyes looking on, this is often the point when I get involved to get it done?? please dont think I am posing as Mr U.K. Super Spanner Man, as I dont realy care if I never swap out another Roller Ring before my 6 bits of Wood turn up to box me in, but dont think I would not like the challenge to test myself against a task, I can pay a plane ride.

 

[KWD]

Hello, we have done 3 ring changes in the last year, 2 Liebherr 904,23 tonne and a Fuchs350 30 tonne, used a crane to lift the top off, simple and safe, for the bolts one lad breaking the bolts loose with hydraulic spanner the other lad following on with a air ratached, there cant be a quicker or simpler way, takes two good skins two long shifts to do.
you lads jacking and skidding, you have to go up a long way to clear the center joint, clean out grease pull bearing out etc and then put it all back
Some people saying they have changed rings in 4/6 hours, well i think they must be strangers to the truth

 

[logsrus]

Yes we have done them in 4-6 hours

 

[KWD]

log is a 709 JD a tonka toy ?

 

[logsrus]

No it's not, sorry to correct you but it's a 790 not a 709. 220 size

 

[KWD]

so you started the job and replace the bearing and 4 hours later the machine was working ?

in your process described above you would not clear the center joint

 

[logsrus]

The 790 is a pretty basic machine, there's lots of room to remove hoses and bolts. the manifold stays w the lower so when you have clearance for the swing pinion you've also got room for the rotary. then slide the whole undercarriage out and use a big impact wrench on the bolts on the bottom. Bada Bing, Bada Boom !!!

 

[KWD]

so how do you get a at least 3/4 drive impact wrench gun in, do both sets of bolts go in from the top,

 

[KWD]

logs just gogle 790jd and it comes up as a compact tractor ?

 

[tctractors]

KWD, I always price up for around the 3 days to do a ring bearing swap by myself (upto 30 ton), that includes loading timber to and from the site plus leaving no mess, the old ring bearing I try to sell to a reconditioner in the south west, but I have already said that once with 2 of us going mental we swapped a bearing in a JCB812 or 814 in a Saterday morning, they are very easy to work on with only a few bolts in them, as for J.Deere kit well its not about in the U.K. that I know of??? I once had a deal to swap a ring on an Hitachi FH200 and agreed a price with the owner, as soon as I had the top plate up ready to swap the bearing the owner turned up, from the comfort of his fancy car he started off saying that I was robbing him and his usual mechanic's would do it for loads less (about £300 less) and to not be thinking of sending him a Bill as we agreed, he drove off in the fancy Chariot, I lowered the top down and bolted it all back together and left it with the knackered bearing still in it, then called him to tell him to get his usual mechanic's to do it as I dont want to cost him undue expence, his usual mechanic's worked on Trucks it was these lads that put me in the frame for the job and are long time pals, they would not do it and the machine was soon sent to an Auction with the new bearing in the lot, the owner of the fancy Car now own's a Garden Centre near Swindon.

 

[mine_mechanic]

i have done dozen's of slew ring's on various sized excavator's very fun job if you ask me.

 

[logsrus]

790dlc

 

[John C.]

I have always pulled the carbody out from under the house as I want to check the landing ring on the carbody and the bottom plate on the house. One could usually assume the ring is flat and there are no cracks in the carbody and the same for the house but I've had more than a few with definite problems that would have resulted in a short life for the new bearing.

I'm not trying to denigrate anyone for not pulling the carbody out as there are plenty of people willing to take the risk of a short life for getting production running again. I do guarantee my labor though and if there were a problem that could have been taken care of while the pieces were apart I know my customers would have no problem asking me to pick up some of the cost of the redo.

To my mind doing a job fast doesn't necessarily mean getting it done right. I prefer no short term do over.

 

[Coondog]

Tc, your 245 is still 80k lbs less than my 375. I am no sure about your plane ticket comment, if you suggesting that this dumb dumb fussy American mechanic come to the UK so a real mechanic can show him how it's done, I pass. Not because I'm afraid I would get shown up as I'm sure I would, but because I can't take my gun with me. I don't g anywhere without at LEAST one. I still don't really see how doing it your way would save me any grief because my grease channel has a welded on riser in the mddle, so regardless if swing motors are removed or not. Still have to clear ten inches.

KWD, a crane would be nice, however t get a crane that would lift 140k to come to my area would cost more than it is worth by a long shot. And jacking was not that bad. In fact that was the easiest part. Foot on the pedal and pump away. Lift right out and up and clear and easy. A jd 790 is about a 60k lb machine. That's like the most popular size of hoe, biggest thing you can transport without too much extras. Still overweight, but not too much. I feel that would be more difficult to remove the ring bearing on than the one I did, which is 4 1/2 times larger. All I had to do was remove 42 bolts(2hours), remove 6 hoses(30 minutes), removes final keys(1hour), jack up house ten inches(1hour), pull carbody out( 3 minutes!!!!! huge waste of time apparently), pull out 60 bolts with an 1 1/2 impact ( 20 minutes), and lift bearing out ( 10 minutes). Times are decreased going back together. Everything is simply cleaned in the middle there, did it all the cleaning myself, took me 2 hours.

John c, I hear you barking, I agree that faster is not better. I was concerned going into this job. Once we got started it all went really smooth. And easy. Only about two hours of it did I ave to spend under something all stooped over because the ceiling prevented e from standing up straight. Just seems better to me in all respects to the job, safety, lifting, cleaning, inspecting repairing, everything.

Mine mechanic, your right. It was a fun job, I enjoyed it very much.

 

[theironoracle]

coondog, are the bolts that retain this ring to the track frame inside bolting down perhaps? on these smaller machines mentioned i think most of the bolts are all external bolting up from the outside! most don't have room for a 3/4" impact let alone a 1-1/2" impact, just thinking of the differences between the jobs. when working on projects i usually don't have the luxury of having other expensive equipment around to help so i always make plans accordingly..

tctractors, great move bolting that machine back together!!!!! and it is always nice when others in your field have your back to give the customer what they deserve. my customers always have the option of time and materials or quoted, if they don't trust me then they can find someone else as i see it, i go out of my way to be more than honest with my customers.4

i can't believe this thread is on 4 pages i would still like to get some pics in it though, sounds like maybe this week i can get to my job, i pray everyone has a productive and safe week...........theironoracle

 

[tctractors]

Coondog, the 245CAT was a tuck up to me as I had some work jacking it up (by hand) as the timbers started crunching down under the weight, I had to re-crib the job useing fresh Baulks and Steel plates, I was told that it 's weight was in the mid 40's Long Tons or 45'000kgs but it was hard work to poke up in the air, I later was told it was around the 79'000 kgs as rigged so my pants where pulled down on this 1, the plane ticket is for me as I could do with a Holiday, I dont have a Gun but I do have a Swiss Army style pen knife somewhere ? if I can find it, on the your way and my way thing, it all makes no odds as the job was done with no Drama's, the grease path is the common thing to find in most excavator Carbody build ups, if the swing box/s are removed you save a massive amount of jacking, height = danger on this scale, you said the pinion hangs down 10" so please re-think your comment here, In my mind I would have not even thought about doing your job as you did, but its your job and with this 1 and 2 more done you would have done 3, the main thing is driving/pulling out the Carbody, John C said he always does to safeguard his good name and the Customer, the fact is I never do I just get em' swapped and get my coins, if the Carbody is any good with no cracks or welds things are going back together, its not very common to find hidden damage other than rust areas these days.

 

[theironoracle]

ok, so i finally got to do my first rotec bearing job. Things did not go so well to begin with. After jacking machine up and repositioning blocks for the third time i had it about 8''s in the air and one of them broke and the machine fell to the right (super slow motion no crash or nothing) and stopped luckily before it slid clear off the carbody! Looking back at the pictures i think what an idiot i had two of those block courses parallel to each other, it didn't start that way but somewhere along the line i got in a hurry and it about cost me a career. Gathered my self went and got about 2x's the blocking i started with and proceeded with job not without tying machine to a larger machine with rigging (blue lifting ring) while i was moving it, never used the jacks again just kept teatering machine back and forth with boom movement. I did end up with a hydraulic torque wrench and used it to break all of the bolts loose amazing little tool!!!!

 

[theironoracle]

finished and back on the ground..........theironoracle

 

[caterpillarmech]

Looks good. Were you wore out after throwing all of the cribbing?

 

[Mike L]

Nice job. Were you able to keep your time close to your estimate?