Questionable wizard
Well-Known Member
From a mechanic point of view (same for Cat or Terex equipment), I would have the air tanks cleaned (i.e, take a pic of how your lines connect to the tank, remove tank, wash out, pour in one pound of 1/4" steel ball bearings (source from McMaster Carr) and a gallon of muratic or proprionic acid (Lowe's, Home Depot), plug all holes with steel plugs, place on a one yard cement mixer and inflate a tire inner tube against it to hold it in place. Run mixer for 2-4 hours. Remove plugs carefully pointed away from you wearing PPE. Pour out contents and thoroughly rinse. Dry quickly with a torpedo heater. Pressure test. Take tank to a radiator shop that coats tanks and have the interior coated). Reinstall. Sourcing a tank to match and have all the ports in the right direction will be a challenge.
Then I would purchase a AD-9 air drier from a truck parts shop and plumb in. Air line schematics are available. Also install a Stemco automatic drain valve in your wet tank (the first tank after the compressor or air drier). The Stemco valves really work. Alcohol inducers are a Band Aid. There is a reason you don't see OEMs using them. Sure you can get by, but solving the moisture problem is the right way for a solution. You may have a compressor that is generating oil. Air drier and drain valve will get rid of it.
Replace your pressure protection valves with new (this is the first valve at a tank port feeding components like air shifter, seat, etc.- it shuts the accessories off if tank pressure drops too low to ensure pressure for brakes). They will have garbage in them. The Sealco ones for truck applications are inexpensive.
I usually replace the Rotomax brake chambers on the construction equipment with 36-36 truck maxis. They handle misalignment of the operating rod without binding much better than the Rotomax, and are 25% of the price. Parking brake spring force is similar.
If your often top loading the scrapers, switch your spill rack around so it act like a funnel so the excavator has a bigger target. Most are modified this way in NZ as they don't have as many haul trucks. The scrapers do double duty as haul trucks, plus they can spread their loads. If you want more capacity from a Terex top loading, put 12" sideboards on. Just be smart about it.
I question whether Cat 621s being single axle drive will motivate adequately when ground conditions get soft or smeary. Here in Ohio, the JD 862s we had many years ago had to be pushed everywhere with a dozer when conditions were soft.
Then I would purchase a AD-9 air drier from a truck parts shop and plumb in. Air line schematics are available. Also install a Stemco automatic drain valve in your wet tank (the first tank after the compressor or air drier). The Stemco valves really work. Alcohol inducers are a Band Aid. There is a reason you don't see OEMs using them. Sure you can get by, but solving the moisture problem is the right way for a solution. You may have a compressor that is generating oil. Air drier and drain valve will get rid of it.
Replace your pressure protection valves with new (this is the first valve at a tank port feeding components like air shifter, seat, etc.- it shuts the accessories off if tank pressure drops too low to ensure pressure for brakes). They will have garbage in them. The Sealco ones for truck applications are inexpensive.
I usually replace the Rotomax brake chambers on the construction equipment with 36-36 truck maxis. They handle misalignment of the operating rod without binding much better than the Rotomax, and are 25% of the price. Parking brake spring force is similar.
If your often top loading the scrapers, switch your spill rack around so it act like a funnel so the excavator has a bigger target. Most are modified this way in NZ as they don't have as many haul trucks. The scrapers do double duty as haul trucks, plus they can spread their loads. If you want more capacity from a Terex top loading, put 12" sideboards on. Just be smart about it.
I question whether Cat 621s being single axle drive will motivate adequately when ground conditions get soft or smeary. Here in Ohio, the JD 862s we had many years ago had to be pushed everywhere with a dozer when conditions were soft.
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