Two days ago I had a front truck on a:crying: Kato SD70ACE start binding and causing a hop and clicking of the locomotive. Of course, Kato has no replacements anymore. Then, last night one of my Atlas 8-40C locomotive began doing the same with the front truck. I called Atlas this morning, and of course, they have no replacement parts. Sigh!! Anybody else had such luck as this. I've already replaced trucks on several other Kato units with the same problem, but was able to get replacement trucks from Kato. No such luck this time.
Sounds more like an issue with something in the gears than a defect with the trucks. And adding to that is the fact that you have it with two different manufacturers.
Maybe something in / near the track getting into the gearing. Did you recently do some form of fine work along the track? Maybe ballasting?
I agree. Two different branded engines, with the same problem so closely timed and I'd start thinking they're ingesting something into their gear trains.
One possibility is a piece of ballast embedded in a gear cog, especially since only front trucks have been affected. The ballast will be virtually impossible to see at the base of the cog without a magnifier because it will be coated with lube and the same color. I use a dental pick to remove it, but any long slender sharp point will work...carefully.
Agree with the above too and have had this happen recently with a couple locos. In both cases, the offending piece of debris was so tiny and hard to see I missed it the first several times I looked (with magnification). It's amazing that such a tiny foreign body in the gears can cause so much havoc like what you described.
I agree with all the above responses, Had a small piece of ballast crawl up into the gears on my Model Power Mike and bind the gear and bend over the pickup wipers. That was an adventure to fix!
Kato Aces are prone to this. I have had several do this. Take the truck out and even take it apart if necessary and clean each gear carefully. Sometimes the trouble is from a small piece of lint or ballast that you may not even be able to see. Put it back together and it will work like new..
When I run my equipment at my club I always find coupler trip pins clinging to the locomotives due to the magnetic fields around them. The trip pins are from accumate couplers. Some are from my cars and I have been replacing the trucks and couplers with those from Micro Trains. Others are from fellow club members who don't know they are missing. So far none have been ingested, yet.
Best way is to dismantle the trucks completely, I use an Ultrasonic cleaner to clean all the parts then. After reassembly, run a piece of Masking Tape (Tamiya is my choice) or Kapton Tape along the underside of the truck. The SD70Ace in particular has extremely fine gears and with the sprung centre wheels is very prone to this problem. If you have replaced other SD70Ace trucks for this reason, don't discard them, strip them and clean and you can bet they will be OK again (unless they have been melted).
I first started to notice the same problem with my SD-70M's because Kato switched to a different mech on the newer M's & also on the SD-70ACe's. If you remove the trucks & seperate the drive shaft & worm assembly then place a truck on a short piece of track so you can get a up close ( using a magnifying glass ) look into the gears as you slowly push the truck along the track I guarantee you will find some type of debris in a gear tooth. remove the debris reassemble & you troubles are over. Some folks have suggested placing a small piece of tape over those small openings along the bottom of the truck.
I usually run Masonite slider cars in each train on my layout and at the club to keep the track clean. I am going to make a magnetic pickup car with a Micro Trains uncoupler magnet glued to the underside to attract loose trip pins, track spikes and other metal debris before they get into the locos mechanism. It will get pushed around ahead of a loco.
I have had ground foam, ballast, etc, sucked up by the gears in my locos also. I try to keep the area between the rails as clean as possible and I also run my Atlas track cleaner with the vacuum tool atached. I wonder why all of the manufactures of N scale locos put cut-outs for the gears at the bottom of the trucks? I understand that they have to do that to make clearance for the gears, but why don't they just make the gears smaller? You don't see these cut-outs in HO scale.
This thread brings back memories of cleaning the lead truck of a Kato E8 after it struck a "pedestrian". Anyone else ever clean pieces of a Wolf spider from their mechanisms ???
Sounds like the cleaning option is better than spending money on new parts. This is more so if you can find replacements.