digging over drive motors

leeroy said:

Gday everyone.Thought i might chuck my two bobs worth in.I work at a Copper/Gold mine in South Australia operating a Leibherr 996 excavator.Regarding travel motors,the only time i will have the motors forward is walking off a bench(with a 30 degree ramp),digging ore as to not mess up our markup and taking out your corner after cutting a bench or picking up your tail in a double bench setup.Other than that its all over the idlers,stability,wear and tear etc.

Cheers Leeroy.

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Welcome to the forum!!! Any chance we could see some pics or video of that awesome machine that you run?

Yeh no worries i would if i could.It says i cant post attachments yet.

you can now go for it!

have a lovely pic to explain all but for the third night running I cant upload them

Reuben said:

...but on a dozer the spokets are on the back because of the engine/tranny layout... for the most part a dozer travels in reverse as much as it travels forward.

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Reuben, you are correct in every sense of the word, however, a dozer does 90% of it's workload whilst traveling forward, PULLING the tracks underneath the undercarriage. Back dragging, reverse ripping, or any other kind of weird things operators do with dozers doesn't hold a candle to pushing a fully loaded blade out of the bank.
Everyone else, you guys have thousands of right answers that I fully agree with and put in place as safety measures and good practices while I'm working as well as having anyone else work for me... "Work and travel with the idlers forward today, or work your way towards traveling home for the day. You pick."

Deere9670 said:

Welcome to the forum!!! Any chance we could see some pics or video of that awesome machine that you run?

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Heres a few pics.

Iron Horse said:

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If you walk forward especially up hill with the sprockets forward you are pulling slack chain from the top (and against the idler spring)and forcing it under the undercarriage to move . This loose chain under your rollers is not an ideal "track" to run the rollers on . Also because the sprockets are not pulling from the bottom and forcing the machine forward they are pulling from the top (the opposite direction to the intended travel and still are expected to move the machine forward . This creates great stress and undue wear on the walking gear .

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Post number 11 from the "RUBBISH" poster .

hhmmm

when we dig long sewer or water trenches ill put the idlers in front. but when we are digging a 40 by 60 foundation on a 50 by 100 lot i really dont bother to make sure its right. we got 11,000 hours out of our sprockets and chains on the e120b, 315l and 320l. the machines have been in every type of site from ledge to sand and digging out ponds .the uc was replaced because it simply wore out,,, never have had any final drive damage.and i know cat says to dig over the idlers.and i understand why but unless your on some serious ground all the time i really dont think it matters that much . from what ive seen the machines are pretty worn down by 15000 hours but they still track fine. i can see how rocks falling on the sprocket can be more pricey than idlers but i think the hype is overkill.

It was just YESTERDAY that my foreman decided that he could load the ADTs (loose topsoil/no digging effort) more effeciently than I could with our 345BL... he reposition the hoe so that he could track his way across the berm in one straight line, HOWEVER, his longest reach and greatest load was when he was reaching (way) out to load the truck while perpendicular to the track carriage. About ten minutes later while I was farting around on the pan, I looked up on the berm only the see that Mr. Foreman had found out the hard way why I had strategically posistioned my drive motors BEHIND me, as to add to the counter-weight, while reaching way out with a fully loaded bailing bucket. Sure... it took me a little longer to reposition myself and get 'seated' for the next couple truck loads... but it took a lot longer to figure out how to get the hoe's bucket out of the back of the truck and it's tracks back on solid ground (the hoe tipped off the berm, it was a long ways down, and the hoe couldn't simply push itself back down like everyone is imagining). I laughed for quite some time, then loaded trucks for the rest of the day while I believe the foreman went to go get some fresh underwear

I don´t know about the rest of you all, but if I can´t dig over the drive motors.....I don´t feel like I´m working.

leeroy said:

Heres a few pics.

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how many scoops can you load one of those bad boys with?

Can this information about digging on the wrong end be found in any books or OEM publishings? I would imagine its really bad to dig over just one motor then.

Yep, it can be found in the operation and maintenance manual.

Dominion 410 said:

I think Deas Plant has the right train of thought on this subject.When I started operating excavators it was on old Poclain RC-200's .

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Now it would show my age if i said i learnt on a RC 200, GC 120 , LC80 and small TSC Poclain........ Memories

Now one of the main reasons for not digging over the track motors was that the track drive motor were exposed on the inside of the track frames an were subject to being knocked of hence the recommendation of the manufacture was not to dig over the rear.

a lot of the other reasons mentioned are correct as well.

Leroy,

That's a bigun!

And right hand steer too. She would be great on British roads.

I drive big and small ex800_5 385 down to tb008, I love 13 and 20 toners. Live the hitachi 120 , 220,300,400,700 dash 1 best built machines ever in the wirld way ahead of cat, cost less to run and dont break down every time you need them. However this digging over the idler will stand on a larger machine say over 300 and upwards, but with anything under 30 ton its a load if crap, if your clearing bushes and trees, let it b ev withan ex60 ,120 or 200 your going to be using full swing 360 thats why you have it, and yes a 60is big enough for the job if your an operator amd not a talker, if your in soft ground you want your motor under the cab, atleast if the machine nosedives the idler is up an d there is no fear if a track popping off under water,peat,with the root oa tree or something etc etc,,, as for bringing a tree in to the cab , please sir stop driving, your the reason the body shop is flat out straitening cabs and panels anspraying, but for bigger machines rockbreakers are ment to be operated infront of idlers upti 22.5 degree angle slewing left or right, same dir rippers ananyone qithan t cop on knows thet loading rock or digging muck ,you dig straight ahead and load at 90 or 180 its common sense.
If you dont know this your not a machine operator or owner.

I drive big and small ex800_5 385 down to tb008, I love 13 and 20 toners. Live the hitachi 120 , 220,300,400,700 dash 1 best built machines ever in the wirld way ahead of cat, cost less to run and dont break down every time you need them. However this digging over the idler will stand on a larger machine say over 300 and upwards, but with anything under 30 ton its a load if crap, if your clearing bushes and trees, let it b ev withan ex60 ,120 or 200 your going to be using full swing 360 thats why you have it, and yes a 60is big enough for the job if your an operator amd not a talker, if your in soft ground you want your motor under the cab, atleast if the machine nosedives the idler is up an d there is no fear if a track popping off under water,peat,with the root oa tree or something etc etc,,, as for bringing a tree in to the cab , please sir stop driving, your the reason the body shop is flat out straitening cabs and panels anspraying, but for bigger machines rockbreakers are ment to be operated infront of idlers upti 22.5 degree angle slewing left or right, same dir rippers ananyone qithan t cop on knows thet loading rock or digging muck ,you dig straight ahead and load at 90 or 180 its common sense.
If you dont know this your not a machine operator or owner.

We rebuild only finaldrives, prodominently hydash drives. to keep it brief and clarify when digging over finals when the boom is perpendicular to the tracks yes it can degrade the main bearing races quicker by point loading the balls and with constant rocking motion wear vertical lines on the two races eventually going through the hardening.When you ask the customers they'll admit it too, as they don't all come in with this type of wear on the main hub bearings.It has meant replacement of an otherwise o.k. bearing for some people as running them again means the balls are running over "ruts" and they won't last long, so seeing it first hand from a repair point of view it does leave a definite signature on main hub bearings over time.

I was told you should dig over the idlers, 20 years a ago I was laying pipe, the operator thought otherwise the fairly low hour JD excavator he was operating had sprocket damage. See told ya?

Our Takeuchi excavator have the blade in front of the idlers so we often dig over the sprockets. Maybe rubber tracks help?