Frequently Asked Questions

Here are some of the most common questions we have recieved. We hope this helps. Be sure to let us know if you have additional questions.

  1. What is the difference in Tier-3, Teir-4 interim and Tier-4 Final machines?
  2. What is the best way to judge an Undercarriage?
  3. Why buy a used machine?

What is the difference in Tier-3, Teir-4 interim and Tier-4 Final machines?

(Answer simplified)

  • Tier-3 machines(Pre 2011 models) don’t have the same emission standards as Tier-4 machines, Tier-3 machines have a much more simplified intake and exhaust system that are easier to maintain.
  • Teir-4 Interim machines (2012-2015 models)  typically have a DPF (diesel particulate filter) that needs to be changed or cleaned after a couple thousand hours of use. Cleaning or replacing these filters depends on the use of the machine, if it has spent most of its life under a heavy load then chances are it will need to go through the regen process (Regen adds fuel to the exhaust system to burn off the particulate in the filter, this creates heat) more often and will have to be replaced more frequently.
  • Teir-4 Final machines (2016 and up models) use DEF (diesel exhaust fluid) along with a DPF filter to clean the soot out of the exhaust before it leaves the machine, this is the cleanest running type of machine, but you have the added cost of DEF and it must be kept very clean or it can cause damage to the DEF system creating unwanted repairs. With the DEF after treatment your DPF filter will have a longer life.

Year and make vary as to which Tier machine you might be looking at, hopefully these answers will help you.

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What is the best way to judge an Undercarriage?

Typically the first thing you see when you look at an Undercarriage (UC) is the track pads, these can be fairly easy to judge especially if you have seen other track pads on similar machines, but if you haven’t here is a quick run-down…

  • Grouser height: 
    This is the cleat that makes contact with the ground, in almost every situation if this grouser is roughly the same height as the track pad bolt then the grousers are worn out.
  • Track Pad: 
    In some situations the grouser may still look like it has some life left, but the leading edge of the track pad may be very sharp and the pad itself may be thin. This will allow the pad to flex or bend whenever you track over rocks or stumps and this will cause premature wear on the rest of the UC.
  • Rails/Chains/Link assemblies:
    This is the chain system that your track pads bolts to. It has a few moving parts, the link, pin and bushing. You can think of this as a bike chain with the main components being the same just on a larger scale. If you’ve ever ridden a bike you know how important this part can be. On a machine it is much more important to watch because if it gets loose or worn it can and will fall off. Then, you have a machine that will not move…
  • Links: 
    These are not usually the first part to wear out on the chain, they should typically last the life of the UC. Look for sharp edges, or the bottom of the link where it makes contact with the other moving parts of the UC, if it is not flat but wavy it probably has wear.
  • Bushings: 
    This is the part of the chain that comes in contact with the sprocket, it is usually the first part to wear out on the UC. But don’t worry, the bushings can be turned 180 degrees and you know have a fresh side of the bushing to wear.
  • Pins: 
    This is what the bushing rides on and connects the links of the chain. These are typically sealed and lubricated to help them last longer, the seals can go bad causing the pin to wear out (this is common and very hard to see) best practice when you inspect a machine is to hop on the track with one foot on each side and rock left to right, if it is worn badly you will see and feel heavy movement.
  • Sprockets: 
    Sprockets usually wear evenly with the bushings, if you see a sprocket and the pointed edge is sharp to the touch or rounded off it is most likely time to replace it.
  • Rollers: 
    On most machines you have 1 or 2 carrier rollers, these are the rollers on the top side of the roller/track frame that keep your tracks from rubbing on the track frame. These will start to roll where the link makes contact the more it rolls, the more worn it is, when they are new the will be flat. When it comes to rollers the same judgement is used for the bottom rollers, bottom rollers wear faster because they have more contact with the material you work in and they carry the weight of the machine.
  • Idlers: 
    This is the round wheel in the front of the track frame that helps keep the track in place, and also with the help of grease and the track adjuster keep the track at the correct tension to avoid premature wear, it shows wear like the carrier rollers, if it is rounded on the edges or shows to have sharp edges it probably has some pretty substantial wear.

Supporting Images:

When it comes to judgement on the UC, all machines are different… From dozers to excavators, all track machines wear differently especially depending on the material and soil conditions you work in.

When I judge a UC on a machine I try to use my best guess on a percentage, for example: If I say the machine has a 60% UC this means that the pins and bushings are very close to needing to be turned along with sprockets being replaced.

I hope this helps, I am always open to answering questions.

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Why buy a used machine?

It’s just like a recreational toy, let someone else take the hit on depreciation! If you have some history and you know the machine was cared for, then it will be as good as new for you, as long as you care for it like it makes a living for you.

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If you have a question that is not answered here, please contact us.

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Why Choose Us?

These are just a few of the reasons people choose Granite Mountain Machinery when looking for used heavy equipment.

Wide Variety

From low-hour late model tractors, to older equipment, there is a wide range to choose from.

Conveniently Located

Based just outside of Atlanta, GA, provides us the ability to service any of our customers needs.

We Do It All

Granite Mountain has its own yard, shop mechanics and lowboys.

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Granite Mountain Machinery was established based on one principle - integrity.