Saved from the scrapper

[toyman01]

Boy I'm glad I found this site!!! Just aquired three JD 420s in a million peices. As soon as we finish a friends JD H the crawlers hit the hot seat. We have enough parts to build one without buying anything big. Having restored several tractors the engine, transmission and sheet metal should not be a problem. The undercarriage and finals will be another story.

One quick question. This crawler will be for play and show, probably run 20 hours a year. If the undercarriage is 80-90% worn out should we rebuild it anyway? How long does it take to use up the last 10-20%?

This is probably the first of many questions. I appreciate all the effort you guys put into keeping all the info flowing.

[Lavoy]

As a general rule, when someone says their undercarraige is 80% worn out, it really means that it is about 130% worn out. This is not an accusation of you in particular, or anyone in general. But, if you actually looked at an undercarraige inspection form, you would find that the tolerances are a lot lower than you would expect.
Worn pins and bushins will greatly accelerate sprocket wear, and may be difficult to keep the tracks on. Worn rollers will wear the pin bosses off of the rails, and there is no fix for that. If you are going to run quite worn undercarraige, do so with the knowledge that you are likely running it to destruction, and will have to replace pretty much everything. Given that replacing an undercarraige will cost as much or more than a crawler, make very sure that it what you want to do.
Lavoy

[toyman01]

I haven't put a tape on the tracks yet. They arn't on the crawlers and are rolled up. Hopefully out of eight tracks and sprokets I can come up with a set that isnt completly worn out. Of the eighteen bottom rollers i got it looks like at least one set is in good condition. Two of the front idlers appear to be servicable. I guess we will have to see how far gone they are and bite the bullet if they are junk.

[JimAnderson]

Lavoy,
This is the first time I've heard you mention pin boss wear.It seems
that everyone looks at rail or roller wear and never even gives a second
thought to this wear point.When you put in new pins how much wear do
you deem reasonable?If the roller flange has eaten into the pin is the is
the rail shot? Just wondering. Also does anyone have the dimensions for
the front idler? I am looking for OD of the running surface and the overall
width of the vertical flanges.JimAnderson

[Lavoy]

If the pin boss is worn away some, I guess it doesn't necessarily mean the rails are shot, but it does mean that the rollers are shot and need to be replaced. I have seen rails with decent height, but the sideways wear is so bad that they are not salvageable.
Lavoy

[teighs]

What is the pin boss? How do you tell if the rollers are worn?

[JimAnderson]

teighs,
The pin boss is the projection in the track chain where the track pin is
pressed in.On new tracks the pin boss is a round projection.In case of
the early John Deeres this boss is about an inch and three quarters in diameter.On used tracks this round projection takes on the appearance
of a D.This is caused by wear to the rail surface that touches the roller
and by wear of the roller itself.Wear of these two surfaces causes the
roller flanges to come into contact with the bosses .
Roller wear on machines with rock guards can be difficult to determine
because you can only see the first and last roller.If the flanges are real thin,missing chunks or missing altogether then the roller is shot.The run
ning surface is about .400 thick on a new roller.I would consider .200
or less as being worn out.I have posted rail dimensions for new tracks
in the FAQs section and new roller measurements in a previous post
if this helps.As Lavoy has pointed out heavy pin boss wear indicates
worn rollers.JimAnderson

[teighs]

OK, that makes sense. I have a straight 350 and the pin bosses are D shaped. Does that mean the ends of the pins need to be built up to prevent further wear on the pin bosses, or is there enough meat to the links to not have to worry about them?

[teighs]

Maybe I got it, sorry its Monday, if the height of the links gets too low then the chain rides too low in the roller causing pin boss wear on the sides, correct?

[JimAnderson]

teighs,
In a nut shell yes.There is more surface area on the rails than the
rollers so in most cases pin boss wear is caused by worn rollers. There
isn't a lot of clearance with even with new components so that even
with new rollers and worn rails you will see pin boss wear.JimAnderson

[digitup]

Worn out pin bosses let the outside flanged rollers bang on your chain as they come to the boss .When the tracks are that worn out on some machines this would be the first indicator On D3 and D3B cats original chain as well as the Bearco chain used on TD7&8 the bosses would literaly smash the outside flange rollers off .So the optional all inside flange roller was popular on them and did not work worth a Damnd !!!But Deere did not have this problem till later in track life although it dose exist .Now if you have roller guards park on high&dry ground while laying with your head on the ground [In the passed out position] look for clearance between the rollers and the thicker area around the pin.If you see surface contact between these two then the bosses are beating on your tracks. If you dont have roller guards it will be easyier to see just standing there . Lavoy mentioned that track wear is not quite a science and no two opinions will be the same this shows up when you have newer tracks and less wear just mention trading your Deere dozer to the Cat sales man and you will quickly get a high side % of wear.Then go to your Deere sales man and mention a number 20% better than the first opinion and he will stick with that just to make the sale .Always go for an open opinion :not a sales mans word I DIDN'T HAVE TO MENTION THAT DID I.Digitup.

[Tigerhaze]

I thought I would throw in my $0.02, based on my limited experience with my 2010 loader.

I purchased the crawler knowing that I had a significant amount of undercarriage wear- I am under some time and short-term budget constraints which made it harder to wait for the right machine to come along.

Anyhow, the majoirty of the wear has seemed to occur on the track shoes (I believe mine are the "snow" pads) for the loader. While there is a significant amount of wear on the rail surfaces (and internal pin wear as well), the rollers have yet to contact the pin bosses. I have a feeling (based on current usage and wear) that I will wear out the pads and/or start bending them before the bottom rollers cause significant wear on the pin bosses. The sprocket and P&B wear is moderate, but not as bad as the pads. My other big problem is that the hydraulic adjusters are leaking down and allowing the track to jump the bottom rollers on tight turns or uneven ground. I've usually caught it in time.

It doesn't really matter much in my situation since, like Lavoy stated, I am driving the undercarriage to destruction. The pads are too far gone to salvage. I plan on rebuilding my undercarriage with 350 rails once I get to that point.

I think you have to look at how much work you intend to out it through; I am really giving my 2010 a workout right now by borrowing soil from one spot and tracking it to another along with significant site grading and some smaller tree removal. I would expect significantly less wear in the same time period if I was using my Model 50 backhoe attachment more extensively and not doing so much grading and soil borrowing.

Again, my $0.02 based on my limited experience with the 2010 loader.

[digitup]

I have found that pins touch the bosses twice as fast as you think As the rollers wear down while the rail height is also wearing down and there is not a lot of room to begin with in there.Also the old undercarages wear out quicker any way as they aren't heat treated near as much as the new ones .I would say it is about 35%rail wear to 65% roller wear and I have seen Two year old machines that owners thought were in good shape but the roller flanges were beaten off the roller unit from side hilling the crawler .This just beats the hell out of outside flanges .if you start to hear a ringing sound it will be a flange departed from the roller [Not an angle getting her wings] .When the bosses are D shaped than you are banging the bosses watch for roller flange wear. plus watch for the roller mount bolts four bolts in all per roller can loosen off when pin bosses are pounded .Then the rear roller sets loose the sprocket will chew on it or worse than that climb it and make a big mess of your day. Digitup.