Uneven rail wear D6RIII

[watglen]

For the experience cat undercarriage guys...

I am seeing extra wear on the right outside rail side. That is to say the rail if bright polished on the side you can see. You can see metal has been removed.

Tractor has 8000 hours on the rollers, idlers etc.

Rails, segments, pads were new at 6500 hrs.

System one series 2 (its not an alligator link, but it has a link that expands when you loosen the pad bolts, so you can field disassemble the chains)

Soil conditions powder dry clay.

I finished a long pull high draft, and stopped to check for heat. The outside roller flanges were warm to the touch, warmer as i moved toward the rear of the tractor. The rearmost roller flange was the warmest. Inside flanges cool. Left side rollers and rails cool.

I tracked forward (low draft, high speed)to the other end of the field in 2nd gear and checked again. The situation was the same but the temps were higher.

So after all that, what would cause the machine to polish one side of one rail.
The other rail sides are not polished bright.

Thx

 

[Delmer]

For the experience cat undercarriage guys...

That's NOT me.

Did you check the alignment though? toe in, caster, camber? One of those doesn't apply, but it's too late to remember which is which...

 

[Cmark]

A couple of things to check;

Idler bearing wear.
Cannon guide wear.
Equaliser bar bearing wear.

 

[Nige]

Agreed. Something's not straight somewhere on the RH side, just a question of finding it.

 

[watglen]

Next time I'm on site I will check the idler bearings, hard bar flex points, and the main pivot shaft for signs of slop or movement.

I suppose if I hoist the machine off the ground with the blade and ripper, I can use a small ex to poke and prod the heavy parts for signs of looseness.

 

[Scrub Puller]

Yair . . . .

watglen

I can use a small ex to poke and prod the heavy parts for signs of looseness.

Yeh, that or you could use a crowbar. (grins)

Cheers.

 

[Junkyard]

Our D5G, smaller I know and not elevated, had strange wear like that too. Front idlers were running crooked, mainly due to the mount being wore so bad they would rock to one side 3/4"-1". Track frame was ok, rollers ok, segments ok. Rails measured ok externally but they had a lot of internal wear and we could push the track from the side towards the machine and see considerable movement. The combination of the two would allow the machine to spit a track on a slope and also was chewing up one side of the rail and front idle similar to what you're describing.

Junkyard

 

[Cmark]

Next time I'm on site I will check the idler bearings, hard bar flex points, and the main pivot shaft for signs of slop or movement.

I suppose if I hoist the machine off the ground with the blade and ripper, I can use a small ex to poke and prod the heavy parts for signs of looseness.

To check the idler and cannon guides, lift the front, put a block of timber under the edge of a track pad and let it down to preload the undercarriage. Make a note of where everything is, lift the machine again and then put the timber under the other edge and watch for movement.

To check the equaliser bar, measure the distance between the edge of a track pad and the machine frame near the front. Steer the machine hard and see if the distance changes. Also look for movement as you lift the front up and down with the blade.

 

[John C.]

To check the hard bar just push down the blade and lift the front of the machine while watching the end of the bar. If the bearing is bad the bar will move before the track frame does.

 

[watglen]

To check the idler and cannon guides, lift the front, put a block of timber under the edge of a track pad and let it down to preload the undercarriage. Make a note of where everything is, lift the machine again and then put the timber under the other edge and watch for movement.

Im not following you here Cmark. Can you elaborate? "under the edge of a track pad to preload the undercarriage"?

 

[Cmark]

The "cannon" is the large chrome cylinder that slides in and out of the rear track frame. It is kept from rotating by two guides. Wear can occur in theses guides and also in the slots in the cannon that the guides engage with.

If you put a block under the outside edge of a track pad near the front idler and let the weight of the machine bear down on it, it will rotate the cannon to its furthest point, either CW or CCW. Make a note of where the cannon is in relation to the rear frame, put a sharpie mark on there or something. Then lift the machine and move the block to the other edge of the track pad. This will rotate the cannon as far as it will go in the other direction and tell you how much wear is in the guides.

You can use the same technique to see how much play is in the front idler bearing.

 

[watglen]

I've got the dozer in the shop now. Visual inspection shows the bottom rollers wearing the outer flanges quite a bit more than the inner flanges. Chains want to run to the outside of the dozer on both idlers, and the sprocket. The carrier roller is also worn heavily to the outside.

The problem is with the right track. The left track shows a little of the same, but not nearly as bad.

Not finding any movement at the hardbar pivots. The pivot shaft seal is dry. There is some in/out movement on the pivot shaft (1/4"), both sides are the same.

Roller bearings are all tight.

This is system one machine. Clock hours around 8500, with new segments, chains, pads, and idler bearings at 6500 hrs.

I will lift the machine off the ground and lower it onto blocks to check for idler bearing movement, cannon movement. There hasn't been much stretch so far on the chains, so there isn't much barrel chrome exposed. Chrome is dry.

I figure I can use a string to check some simple alignments.

I can use blocks to check for movement at the pivot shaft. I am thinking about the pivot shaft bushings here. I might pull the cover off the end of the pivot shaft to look for movement on the inside.

I also wonder how much of this might be caused by previous roller wear. They put new chains on old rollers. Maybe the rollers were worn to one side for some reason to start with, and the new chains are running in the old path.

Next post I'll have some more info

 

[watglen]

Here are some pics. Working on posting descriptions with them

 

[watglen]

More pics. Wish I could insert them inline

 

[watglen]

OK, here we go.

Did a thorough examination.

Started by lifting machine and setting it on one side, then the other, under the rear idler. Slight movement but nothing extreme.

Same procedure under the pivot pin. No movement noted.

Same under front idler. No movement in idler bearing, or cannon. I was hoping to see some rotation of the cannon, but nothing there either. I thought there should be at least a tiny bit. I marked it with marker. It is rock solid. Note that I used a block big enough so that the track pad was entirely suspended perched on the block. The free end of the pad was dangling, with the blade lifted. If that cannon was going to rotate, it would have rotated.

Under the machine, I checked for movement in the 3 equalizer bar pins. Slight movement in one.

Performed the same inspections on the good side of the tractor. Identical results found.

Ran the tracks forward and back, slow and fast. Two of us spent a good amount of time climbing in, under, and around, the track frame. Off the ground, the only thing contacting the chain is the idlers, sprocket, and carrier. Chain hugs all these to the outside. Inside flanges on the bottom rollers are heavily corroded. They haven't been touched in a while. Meanwhile, the outer flanges are worn to the point they are disappearing.

Carrier roller is wearing heavily to the outside.

Scoured the track frame for cracked welds etc. None found. Visually Inspected for bent track frame. Looks fine.

Pulled the cover off the pivot shaft, removed seal plug. Initially it appeared the pivot shaft was not centered in the hole, but cycling the tractor up and down showed no movement at all.

I measured between the track pad and tractor frame at front and rear of tractor. 1/16" difference.

I haven't tried a string line on anything.

How do you check the idler alignment? How do you change it?

 

[turbo8781]

my vote is on worn rollers. Try removing the carrier roller then run the tracks With the machine suspended and see what happens. I know around here the do alot of plowing right down the edge of the road in the bar ditch which is hell on UC as far as twisting the rails goes and making them want to ride to one side. Maybe thats what started the wear on the old rollers and its just tranfering it to the new rails.
just my 2

 

[watglen]

Hello again,

I went back out and checked the toe. It's exactly the same distance front to rear.

Some of the reading I did this aft had me wondering about the track tension. Checked it, it was pretty pretty tight. I may have been running it too tight for a long time. Slackened that off to spec. With the grouse cleats on there its tough to say whether the specs and measurements apply the same way, but I set it at 1.8" anyway. I think it runs a little quieter now.

 

[John C.]

I seem to remember there should be some alignment shims between the pivot shaft and the end cab to line things up with the sprocket teeth. I don't know on System 1 machines if that is true.

When I used to do undercarriages I would string line the center of the sprocket teeth all the way down to the center of the front idler. I would line up the cent of the carrier roller on the string and would know I was close enough to not have problems on the top end. I haven't done high drives so I'm not sure of how to align the sprocket teeth to the rear idler for a check. I suppose you could use a straight edge off the sides of the teeth and run it down to the sides of the rear idler. On smaller machines, D3 Cat and Deere 450 I've seen bent track frames. I've not heard of a D6N or M ever doing that but I suppose it might not be impossible to happen.

I've also seen plenty of machines working side hills do what you are showing.

 

[watglen]

I seem to remember there should be some alignment shims between the pivot shaft and the end cab to line things up with the sprocket teeth. I don't know on System 1 machines if that is true.

When I used to do undercarriages I would string line the center of the sprocket teeth all the way down to the center of the front idler. I would line up the cent of the carrier roller on the string and would know I was close enough to not have problems on the top end. I haven't done high drives so I'm not sure of how to align the sprocket teeth to the rear idler for a check. I suppose you could use a straight edge off the sides of the teeth and run it down to the sides of the rear idler. On smaller machines, D3 Cat and Deere 450 I've seen bent track frames. I've not heard of a D6N or M ever doing that but I suppose it might not be impossible to happen.

I've also seen plenty of machines working side hills do what you are showing.

I gathered up some straight edges and string tonight. Will have another go tomorrow morning.

I checked the parts manual and it doesn't show any shims or spacers, which is weird in my mind.

 

[Dickjr.]

I'm no expert by no means but have been thinking about this ( which is dangerous ). Anyway , I would think the sprocket drive or drive hub with segments would set a beginning point for the alignment of the roller frame. I wonder if you took a small jack and put some pressure on the e q bar , check that , then put some pressure on the pivot shaft to see if it moves outwards at all. I'm not talking about a lot of pressure just enough to see if it moves easily. The only other explanation , is the wear on that side , is the tractor running on a slope to ride on that side , does the operator favor a certain side to push with? Is the operator right or left handed? I am right handed and wear the right hand end bits more which would push the tractor to the left I think. Just thinking out loud here.