pc75uu-2 steel tracks coming off

[wedigskook]

I have a 2000 pc75uu-2 and every time I turn or twist the tracks are coming over or behind the bottom rollers. Especially when I'm on any kind of slopes with weight over the side. I picked each side of the machine up and checked the track tension and both are tight. The rollers seem to have a small lip on them that don't do much for keeping the track on. Is there something I could do to solve this. Also wondering if rubber tracks can b installed without any modification?

 

[rsaint]

How bad are the rails and rollers wore they may be bad enough that there is not enough meat on rails and rollers and play in chains to keep coming off. If that is the case they may have to be fiddle string tight and use bucket to help turn.

 

[Randy88]

Wedigskook, how long have you had the excavator, and how many hours have you run excavators before? As for fitting rubber tracks on your machine, it could be done, but before I'd spend that kind of money, I'd start to replace some of your worn out undercarriage parts a little at a time, how many hours on are the machine, and what was it used for, constantly moving or just sitting and digging somewhere? How tight are your tracks and do you have picutures of the undercarriage parts so we can see what they look like.

 

[mike69440]

Have fun, It took a lot to throw a track on mine.

Wedigskook, how long have you had the excavator, and how many hours have you run excavators before? As for fitting rubber tracks on your machine, it could be done, but before I'd spend that kind of money, I'd start to replace some of your worn out undercarriage parts a little at a time, how many hours on are the machine, and what was it used for, constantly moving or just sitting and digging somewhere? How tight are your tracks and do you have picutures of the undercarriage parts so we can see what they look like.

Agree that you need to find out what up with the UC. I have a 6000 hr Worn UC and it still takes a lot to toss a track.

 

[lumberjack]

Mike, I'd say you have a blown grease seal or something! It looks like you could remove 5 links and still have plenty left.

 

[rsaint]

Would say u have a problem with your tentioner if only 1 side is like that if both your chains are streached.

 

[mike69440]

That's the victory photo of just getting the track back on the idler.

Mike, I'd say you have a blown grease seal or something! It looks like you could remove 5 links and still have plenty left.

Have you ever tried to get the track back on without dumping the grease out of the tensioner? I lost the track messing in the woods and limped it out to a spot I could work on it. Used the machine to pick itself up. First time in five years that i lst a track. My UC is worn but I can still run reasonably tight tracks.

I'd hate to mess with a track on a real excavator.

 

[lumberjack]

Oh, I thought you were implying that picture was an indication of how worn your undercarriage was!

 

[wedigskook]

The machine has 3600 hours. The tensioners on both sides are good. I know the manual calls for 4 inches off the bottom roller but I've even tightened so they were within two inches. I made a set of rock guards for each side and they seem to b helping but if I'm sitting in muddy or loose dirt and spin tracks opposite ways to turn 360 the tracks still wanna ride off the bottom rollers. I went to komatsu dealer Friday and talked to them and I was gonna buy a new roller to bring back and compare it. Because they look alright to me but instead komatsu will send a guy out to measure everything before I go buying things. I kinda have a feeling the bottom rollers edges are worn on an angle and the tracks are riding right up one over. I will try and post pics tomorrow to see what you guys think

 

[Profit]

I would believe that you are filling the chains with loose material when you counter rotate and then drive out of the track. Never hard steer or counter rotate in loose material especially with a worn rig as this is the result. Happens all the time in the tunnels of NYC don't care how big or how small, whether it's an excavator, bobcat, man lift, whatever. If it has tracks my guys will fill em and drive out. Had one guy with a TB175 lost the track 4 times in one day but I cured him. Last time I went down the shaft I threw an 1 1/2"combination wrench directly at his windshield while he was sitting in the cab waiting. Woke him up pretty good and when he asked why the hell I did that told him it was a demonstration of what I was gonna do to him next time I had to come down for a track. Musta worked, he never spit another over the course of another year and a half. BTW didn't throw it hard enough to break the glass, just enough to get his attention. YOU CAN hard steer and counter rotate just gotta clear the track before you move any distance above all, pay attention. :yup

The machine has 3600 hours. The tensioners on both sides are good. I know the manual calls for 4 inches off the bottom roller but I've even tightened so they were within two inches. I made a set of rock guards for each side and they seem to b helping but if I'm sitting in muddy or loose dirt and spin tracks opposite ways to turn 360 the tracks still wanna ride off the bottom rollers. I went to komatsu dealer Friday and talked to them and I was gonna buy a new roller to bring back and compare it. Because they look alright to me but instead komatsu will send a guy out to measure everything before I go buying things. I kinda have a feeling the bottom rollers edges are worn on an angle and the tracks are riding right up one over. I will try and post pics tomorrow to see what you guys think

 

[Randy88]

Wedigskook, when you spin 360 instead of doing it with the tracks, try lifting yoursef up with the bucket and spinning it around instead of tracking it around, saves having to put tracks back on, also in the manual it states to track with the drive sprockets towards the front of the tracks, not the rear, that helps quite a bit too, it helps to keep the drive sprockets tight, so the idlers can take the slack up on the rear. Next question is, what end does the track keep coming off of, drive sprocket end or idler end, if the idler end, is the idler worn in the wear guides, so when its under tension, it actually angles the idler to one side somewhat, one of my excavators had excess wear, and we kept spitting tracks off, once we fixed that problem it pretty much cured the problem. Just a few suggestions to try.

 

[lennyg100]

I would look at fitting central track guides, should fit on with longer lower roller bolts, should help lots.

 

[wedigskook]

I made rock guards for both sides inside and out and as long as I don't twist in soft material everything is good. Komatsu never showed up to measure undercarriage so I never pin pointed the problem yet but it always seems that the track started coming off near the middle bottom rollers

 

[Randy88]

Wedigskook, post some pictures of your rock guards and explain how you did it, some of the rest of us are needing the same thing on our machines, just haven't had time to fabricate any yet.

 

[wedigskook]

bought some angle iron and notched around idler then used aluminum as wearing bar on bottom and drilled and counter sank alan head bolts to hold them on

 

[wedigskook]

tried to post pic of them welded on but wont let me im sure you got the idea

 

[Randy88]

Did you drill and tap holes in the bottom where the rollers fit onto to hold the guards on then or how did you mount them to the machine, great job, nice photo's, thanks for the update