350D track spring problem

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Camp Creek
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350D track spring problem

Post by Camp Creek » Wed Dec 13, 2017 12:34 pm

I have a 350D crawler with 6 way blade and winch. Great machine, The problem is it jumps teeth on the sprocket when backing up. I have tried different tensions on the track no effect. The carrier that the idler is riding on is moving toward the sprocket about 1 1/4”. It skips and moves right back to tight. I have broken the track and removed the spring, it is not broken and the adjuster is not leaking. I took my problem to the JD parts man, he looked the serial # (743518) he said there was a change somewhere before my number and the spring was changed to a different type. A large spring with a sleeve around the bolt, My machine had a lot of work done on the tracks, new chain and pads, sprocket, idler, rollers, literally everything, I’m think the shop (not JD) didn’t catch the change and put the usual spring in. I think the sleeve was meant to stop large compressions of the spring, that’s the issue i am dealing with. The correct spring is not very available, JD could not source it new but got a couple of hits on either used or reman. I guess my question is, has anyone out there heard or dealt with this spring change issue? Where can I find a correct replacement . Any insight into this would be appreciated. Bill

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amos
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Re: 350D track spring problem

Post by amos » Thu Dec 14, 2017 6:55 am

Hi Bill,
Trying to visualize this and when a crawler is moving without load it moves surprisingly easily.If you're getting that much backward movement of the front idler with no load it seems like something is in a bind on the rail/chain.I've worked on crawlers that had been sitting for long periods of time and the pivot point of some of the pins would be seized to the point that on level ground the dozer was extremely rough riding as it rolled over the seized section of the rails. This also caused compression of the shock spring(s) as the seized section went past each bottom roller,front idler,top roller(s) and sprocket.
Easy enough to check: put an operator in the seat and while on ground look for stiff track sections.
Fix is simple to hard: get a gallon can of WD-40 and saturate seized sections then drive crawler till they break loose. If really stuck I've heated with a rosebud and oxy/acetylene rig(not anywhere close to red,just very hot) and that has freed even the most troublesome seized sections.
I haven't figured out how to do it but it is possible to post a link to a video here and a video might help us help you.
Amos
Pushin hard or diggin deep life is good.
What's ahead is what matters. What's behind is already done.
A fool of a man is he who doesn't ask questions...
God gave us 2 ears and 1 mouth for a reason...

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Lavoy
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Re: 350D track spring problem

Post by Lavoy » Thu Dec 14, 2017 8:45 am

I have new springs available, but I wonder if part or most of your problem is worn sprocket, and/or pin and bushing wear causing the track to climb the sprocket.
Lavoy
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dtoots1
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Re: 350D track spring problem

Post by dtoots1 » Thu Dec 14, 2017 9:19 am

another thing about frozen/rusted tracks....is...drive the thing thru snow and water....water is the best rust solvent when moving...surprised mr.Lavoy neglected to point that out.....if you find that is the problem....like Lavoy says...could certainly be worn problems....

of course you may not have snow...we do....last 2 dAYS got 6-8 inches....you don't show your location!

Camp Creek
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Re: 350D track spring problem

Post by Camp Creek » Thu Dec 14, 2017 2:23 pm

Thanks for the reply’s, This is a former county machine, i was able to get the maintainence records for the last 10 years when i. Bought it. Hour meter is accurate they put $11,000 in tracks less that 100 hours ago, it looks like everything is new, rollers, sprocket, idler, chain and pads, when tight the idler carrier is about 4” from the end of the rail so a lot of adjustment left. The sprocket is quite round and looks full depth, track adjusters work as designed, we have the track apart and the spring out and it is not broken that i can see and of course the bolt is intact. The track is laid out on the concrete floor and i see no misaligned chain links (frozen). We did have to lance both ends of the master link to drive it out. The length of the spring is about 1/8”out of spec according to the main. Manual if memory is right 14” about on the spring and 16 1/2” outside to outside on the spring ends?. I am going to refill the track adjuster by squeezing all of the grease out of it and refilling to eliminate any air bubbles. Will check as much of the chain as I can to find frozen links. Otherwise it has to be the spring??? Thanks for the help I did find a used spring, correct # with sleeve, through the JD parts man, new is not available, so he had no choice but to offer used and he found one with the sleeve in the Midwest somewhere and i told him to get it ($225) plus freight. thanks for the help will keep you in the loop. Bill

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Re: 350D track spring problem

Post by Camp Creek » Thu Dec 14, 2017 2:29 pm

If I could figure out how to post pictures I could clear up a few issues. Bill

B Town
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Re: 350D track spring problem

Post by B Town » Thu Dec 14, 2017 6:34 pm

?symptoms on one side or both sides? Sprockets sound to be in good nick. Final drives, bearings, axles are solid? You are certain the sprocket jump happens b/c the front idler and carrier compress toward the rear of the machine and slack the chain? Bruce

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Re: 350D track spring problem

Post by Camp Creek » Mon Dec 25, 2017 11:57 pm

I have discovered that the later 350D’s have a different track spring arrangement, not sure where the change occurred but they changed from a main large track spring with a smaller spring inside to a heavy spring with a sleeve around the all-thread. Have not been able to determine what the sleeve did but the only purpose i can think of is to limit the travel of the compression of the main spring. If that were true it may solve my problem. Does anyone out there have a track spring that conformed to that description. Have the part number up in the shop so can’t reference it right now but the serial # is 743518.
I am thinking of having a spring made up with a sleeve that would not let the spring move as far as it is moving now. If there is a dimension for that sleeve that anyone has I sure would like to have it. Anything helps. Bill

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Lavoy
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Re: 350D track spring problem

Post by Lavoy » Tue Dec 26, 2017 9:53 am

The tube is not your issue. If the spring will compress just backing up on level ground with no load, the spring is bad assuming there are no other underlying issues, which I am still guessing there is. Sticking a piece of pipe in there to compensate for a bad or incorrect spring will be a band aid fix that will result in broken final drive when something occurs that requires the spring to move back to prevent breakage. I have stood a 350 loader on its nose backing up and never skipped a sprocket, so no way yours should do that under normal conditions. Does your spring have the inner spring, it should. I have new springs available as posted above.
As to having a spring made, you have no way to determine what the compression rate should be, and a new spring like that on a one off basis would be thousands of dollars if you could even find someone to make it.
Something is very odd here, just need to figure out what it is.
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Camp Creek
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Re: 350D track spring problem

Post by Camp Creek » Tue Dec 26, 2017 12:16 pm

Is it possible to talk?

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CuttingEdge
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Re: 350D track spring problem

Post by CuttingEdge » Wed Dec 27, 2017 4:09 am

Camp Creek wrote:
Mon Dec 25, 2017 11:57 pm
I have discovered that the later 350D’s have a different track spring arrangement...Does anyone out there have a track spring that conformed to that description. Have the part number up in the shop so can’t reference it right now but the serial # is 743518.
I am thinking of having a spring made up with a sleeve that would not let the spring move as far as it is moving now. If there is a dimension for that sleeve that anyone has I sure would like to have it. Anything helps. Bill
I have that on my late-model 350D, but I honestly think you are chasing unicorns on the spring, and is not going to get you what you need. You have other issues at play here I think. I say that because my bulldozer is in the same shape as yours, completely rebuilt undercarriage, but my track adjusters are blown out and yet even with the tracks 100% backed off, I do not loose tracks, nor do they jump rear sprockets, in reverse or hard digging going forward.

I had the chance to chat with Mark, known here as PongHogVT, about your tractor at length yesterday, and after thinking some about this, I am wondering if you might have a bent axle, or track alignment out of adjustment allowing your track to "climb" the sprocket so to speak. The greatest indicator of this is that you say it happens when backing up. In thinking this through as I type this out...just so we are all on the same page as to my line of thinking; we all know that in backing up, the driving force is placed on the top of the sprocket instead of the bottom. It is therefore conceivable that if your top carrier roller was out of adjustment, (or idler, or sprocket via being adjustment or bent axle), it would allow the track chain to enter skewed and be allowed to climb, but only in reverse.

Think of this like a 15 speed bicycle; sometimes when the cyclist goes to shift gears, the mechanism does not move enough in time to the pedaling so that the chain ends up skipping teeth. It is conceivable that the same forces are being done so here. It is also possible that with all the work done to the undercarriage, that there was some misalignment issues.

Does the issue happen on one particular track, or both?
I have no intention of traveling to my grave in a well manicured body; instead I am going to slide into heaven with a big power turn, totally wore out with busted knuckles, jump off my dozer loudly yelling, Woo Hoo, another Shepard has just arrived!

pondhogvt
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Re: 350D track spring problem

Post by pondhogvt » Thu Dec 28, 2017 7:08 pm

Hi Guys,, just to put some light on Bills situation,, we have been talking for several months on and off about his track problem.. at first I thought it was something simple and him being new to dozers was just not seeing it,, like track tension or broken spring or final drive bearings,, he has sent pictures all along as went thru this,, everything is immaculate,, he has a gorgeous near mint condition machine,, spring was not broken, final drive bearings are tight, track tension was good,, as I explained to Travis (cutting edge) this weekend I am stumped because this is not a junk but a really,really nice 350D... and by the way Travis thanks for the lunch, I appreciated the visit.. so anyway Bill called tonight and said he was buying the John Deere updated spring for his machine,, and I hope it works but I told him I don't think that is the problem unless his is cracked or weak somehow,, but there are no visible cracks..

Like Spock says by process of elimination if all other fixes do not work,,, what is left no matter how improbable must be the problem.. makes sense to me.. so what I am left with trying to diagnose a dozer 3,000 miles away. is bad quality sprocket in the machine process or bad track pitch thru poor machine process... Although Travis might be on to something I didn't think of if the top roll bracket could be bent to mess up alignment..

I gave Bill the correct pitch for a JD350 @ 5.75"s.. maybe he got a bad aftermarket chain, they are DCF brand he told me.. I have no experience with that brand... they look new as do the sprockets in the pictures he sent me... this is when I wish I could stand by the machine when he backed it up so I could see for myself...

But I am stumped,, any help appreciated. Mark. could put a dial indicator on the frame and spin that sprocket to see if it is out of round???
350 loader,350c dozer winch and arch,450c winch and arch,450e winch and arch,D37p komatsu lgp dozer,D85 Komatsu dozer,D8k Caterpillar.

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amos
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Re: 350D track spring problem

Post by amos » Fri Dec 29, 2017 4:29 am

Hi Bill,
Just a thought: a video of the jumping track would be extremely helpful. I haven't figured out how to post a pic much less a video but I bet Lavoy can. PM him and maybe you could send him a memory card with video and then he could post(or he could offer more guidance).Cards are dirt cheap now as is a stamp.
I can fix just about any mechanical device made by man but if it involves more than a click or two I'm about useless on a computer.Click here,cut and paste that,double click this then forward slash that: all Greek to me......
Today I'm off to pick up some more auction treasures: 8400 pounds of tractor weights.Won another auction. Woo Hoo!!
Amos
Pushin hard or diggin deep life is good.
What's ahead is what matters. What's behind is already done.
A fool of a man is he who doesn't ask questions...
God gave us 2 ears and 1 mouth for a reason...

B Town
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Re: 350D track spring problem

Post by B Town » Fri Dec 29, 2017 6:26 am

Some forum members will post a video on YouTube, then refer to that video, here on the forum. Just an idea, esp if you have a YouTube acct. keep us posted, Bruce

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CuttingEdge
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Re: 350D track spring problem

Post by CuttingEdge » Fri Dec 29, 2017 7:07 am

pondhogvt wrote:
Thu Dec 28, 2017 7:08 pm
as I explained to Travis (cutting edge) this weekend I am stumped because this is not a junk but a really,really nice 350D... and by the way Travis thanks for the lunch, I appreciated the visit...
No problem Mark. It was good to get away from the outlaws for awhile, though I noticed even in this reply you did not mention your comment regarding my demise from cancer and your son dating my wife! (LOL) You would make out well. A few hundred acres of land. A nice gravel pit. A nice 350D bulldozer. A chance to get out of VT. (4) granddaughters...oh wait, maybe the latter is a deal breaker! (LOL)

I know you don't go down to the "Off Topic Discussion Section" on here often, but I discussed my trip out to Bernieville (as I call Vermont in reference to Bernie Sanders) to see you. You might get a smile out of it.

All joking aside, it was a nice to meet up.

viewtopic.php?f=4&t=11996

By the Way: What is the difference between Inlaws and Outlaws? (Wait for it) Some people actually want Outlaws!!
I have no intention of traveling to my grave in a well manicured body; instead I am going to slide into heaven with a big power turn, totally wore out with busted knuckles, jump off my dozer loudly yelling, Woo Hoo, another Shepard has just arrived!

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