Determining roller and idler wear on my D3B

If the rails and sprockets are worn out the condition of the rollers doesn't really matter as you don't want to mix and match old and new wear surfaces....that is unless you want to weld build them back up to as new specifications. That's a practice that just isn't done much anymore as the labor is more than replacement costs. The only exception might be the front idler, these are still salvaged. The depth from the inner flange to where the rails run is 0.63 in. new and considered 100% worn at 0.83 in. The flange width is 1.69 in.

Weld on sprocket rims are available to renew them.

OM
I checked my idlers against the measurents you provided and they are better than 80%.
I had the parts guy at NC measure a new roller. The dimensions he provided are 175mm across the flange diameter, 10 mm flange height; so 175 mm - (2*10mm) = 155mm roller wear surface diameter. My rollers are 149mm diameter wear surfaces.

Ideally, I agree that I should replace the rollers when I replace the track chain and sprockets. I dont understand what the downside is if I run these rollers for another 1k-1500 hours more. It seams like the old and new wear surfacees will ger to know each other pretty quick. Am I missing something? Thanks, Rob

That's just the point....putting new with old will accelerate the wear until they mate.
Measurement of % worn is great for the overall undercarriage to determine life left, not to mismatch components.

Of coarse it will work but full usefull life depends on uniform contact surfaces and matching of components.

As far as running your existing rollers with worn out chain for another 1500 hrs or so, that's fine unless it gets to the point where your out of adjustment or the tracks jump off.

What is the track link number that you are running?

I will have to check on the track link #s.

I was planning on putting the new track links and sprockets on and using the rollers until they start hitting the track chain pin bosses.

Lets say that the groove in the wear surfaces was the same width as the new track chain rail; do you still think this will still cause accelerated wear?

Any mismatch in shape will result in some accelerated wear. Obviously the closer to new spec. (no worn groove) the better. Keep in mind that the countdown from new to 100% worn is the heat treated surface that runs about 0.250 in. deep for components on the small tractors.

Rob,
Putting new tracks on 20% rollers is done every day in the real world.You won't even notice any extra wear.If you have 6 roller track frames swap middle rollers for end rollers.
Good luck
Bob

Rob,
Putting new tracks on 20% rollers is done every day in the real world.You won't even notice any extra wear.If you have 6 roller track frames swap middle rollers for end rollers.
Good luck
Bob

[quote="bluox"]Rob,
Putting new tracks on 20% rollers is done every day in the real world.You won't even notice any extra wear.If you have 6 roller track frames swap middle rollers for end rollers.
Good luck
Bob[/quote]

I tend to agree. I grew up placer gold mining. We had a 14A and an early D8H and we did not neccesarily change out all undercarriage components at the same time. Usually we would change them as the wore out. The exception was sprockets and track chains were changed together, or after the pins were turned. That does not neccesarily make it right, but that is the way we did it.

To OM's point. I am sure it is ideal to change them all at the same time. The machine I have looks to have had the rollers and idlers changed more recently than the chains and sprockets.