Lionel 6-38025 TMCC K4 Help

Per the parts breakdown for this engine, the front pilot truck is controlled by the short arm and a frame mounted screw.

If the pilot is free floating and only held by the larger washer and the square tab/ring/hole at the back, then that is wrong.

https://www.lionelsupport.com/...LOCO-ONLY-6308025001

Ensure that screw #68 is holding that short arm to the long rivet and spring to the frame of the loco.

The pin with the spring on it seems extremely loose and I don’t believe it can be tightened since it has a lock ring on the bottom.

This model was sold as an O72 model.  The front truck may have been (loosen-ed) a bit, to achieve O72.   Most noted feature, at the time, was the Optical tether, no wires between the locomotive and tender.  It also had one of the first speed controls.

@Mike CT posted:

This model was sold as an O72 model.  The front truck may have been (loosen-ed) a bit, to achieve O72.   Most noted feature, at the time, was the Optical tether, no wires between the locomotive and tender.  It also had one of the first speed controls.

O72?…….the box says O54 as a minimum…

Pat

@Casper posted:

The pin with the spring on it seems extremely loose and I don’t believe it can be tightened since it has a lock ring on the bottom.

Can you post up a picture, or a even a short video of what’s going on?…..that would be a better starting point than trying to speculate what’s going on, …..Also, flip the engine upside down, and scoot the pilot truck to one side and take a pic, so we can see what parts are or are not there,…..

Pat

I've run it around my O54 layout, i.e IMO. O72 works much better.  Good luck. 

here are some photos, hopefully it helps

Here is a video as well

That looks like someone did a modification to the pilot truck, ……I don’t think there’s supposed to be that much slop, ……I bet somebody tried to get that thing to go around radius it wasn’t designed for, and their attempt was to waller out the hole the pin goes through on that pilot truck,…….the pivot bar & pin are what keep the truck aligned on center with the cylinders…..somebody’s drilled out that pilot truck ….IMO, …..quick fix if you can find a bushing that fits the wallered out hole……or replace the whole front truck, which kinda sucks, …..I’d be looking for a way to fix what’s there,…….

Pat

Shouldn’t the spring be tight, if you lift it up there is no tension on it.

@Casper posted:

Shouldn’t the spring be tight, if you lift it up there is no tension on it.

@Casper posted:

Shouldn’t the spring be tight, if you lift it up there is no tension on it.

Yep, ….but the spring ain’t gonna stop all that slop,….

Pat

@Casper posted:

Shouldn’t the spring be tight, if you lift it up there is no tension on it.

For a quick test, pop the e-clip off, ( watch!..it can go flying! ) and stretch that spring out to see if it at least improves your situation, …..I doubt it will, but nothing beats a try but a fail, ….and you got nothing to lose…..

*but the e-clip,….😉

Pat

I might try finding a shorter pin and clip

@Casper posted:

I might try finding a shorter pin and clip

That’s a backwards approach, …..no need to go hunting for a shorter pin, it appears to be the stock pin & e clip, ….here’s another simple test if you are not comfortable removing the pin, ….cut some little pieces of cardboard, and slit a notch in the pieces,…..shove them under the spring to build the tension back up, and then see if that cures your woes……again, a simpler method would be to simply remove the e clip, stretch that spring out a wee bit, & reassemble, ……if it’s still sloppy, then the hole the pin goes through is wallered out or has been drilled out, ….either bush it, or replace the truck,…

Pat

It looks to me the front centering arm is missing. That is the reason there is so much back and forth movement. It was probably removed so the engine could negotiate tighter curves.

@Chuck Sartor posted:

It looks to me the front centering arm is missing. That is the reason there is so much back and forth movement.

You have to look closely Chuck, it’s there, …..it ain’t missing,……this engine looks like somebody did some mod work to make this engine go through curves it wasn’t designed to do,…..look at every flange, and how slightly ground up they look,…….I’m betting somebody’s done some tinkering on this thing to make it do what it wasn’t supposed to,…

Pat

OK, so the only other explanation is either the pin had enlarged the hole or a round file was used. Replace the truck.

here is the front truck. Is the pin suppose to have wiggle room like that or be pretty tight? I also stretched the spring a little

@Casper posted:

here is the front truck. Is the pin suppose to have wiggle room like that or be pretty tight? I also stretched the spring a little

We didn’t get any pics or video,……we’re we supposed to?..

Pat

@harmonyards posted:

We didn’t get any pics or video,……we’re we supposed to?..

Pat

Sorry

@Casper posted:

Sorry

No worries, …..we’re trying to help you out, …..either that locomotive has a billion miles on it, or somebody wallered out the hole, as Chuck said, with a round file, or an angry drill bit, ……that truck is pretty much ruined, ….you either need to police up the oblong looking hole with a bushing if you’re handy, or again as Chuck recommended, replace the truck with a new one from Lionel,……Legacy K4 Pacific same as,……so you should be able to get one …..in any case, this is how it should look,….slip fit, with minimal clearance …..

Pat

@harmonyards posted:

again as Chuck recommended, replace the truck with a new one from Lionel,……Legacy K4 Pacific same as,……so you should be able to get one …..i

Pat

Vernon has a link above to the parts  for this exact loco.  The old early 2000's Tmcc k4&1/2 if the truck is available.

I'm not sure if the Legacy k4 pilot truck is the same being of K Line origin.

@RickO posted:

Vernon has a link above to the parts  for this exact loco.  The old early 2000's Tmcc k4&1/2 if the truck is available.

I'm not sure if the Legacy k4 pilot truck is the same being of K Line origin.

Quite right Rick, …..I keep forgetting about that TMCC model being different ……I believe that engine even has a rear facing large Pittman, …..no??…..

Pat

@harmonyards posted:

…I believe that engine even has a rear facing large Pittman, …..no??…..

Pat

Yes, the extra longgg bel paire firebox accommodates it quite nicely. 😉

@harmonyards posted:

Quite right Rick, …..I keep forgetting about that TMCC model being different ……I believe that engine even has a rear facing large Pittman, …..no??…..

Pat

Is it ok to oil any of this area, has a slight squeak to it, sounds like it’s coming from the motor. I also want to thank everyone for all there feedback!

@Casper posted:

Is it ok to oil any of this area, has a slight squeak to it, sounds like it’s coming from the motor. I also want to thank everyone for all there feedback!

Absolutely you want to oil that!…..get a good dose of oil on those shaft bushings!….you should be able to slightly rock that motor shaft back and forth very gently by pushing and pulling on the flywheel,…you need to oil both ends,….apply with a pin oiler, syringe, or on the end of a toothpick to get to the nose bearing behind the flywheel,….rock the shaft gently back & forth so the lubricant works it’s way into the bearing, & you’ll be fine……regular motor oil works best here,,……whatever weight you happen to have in the garage would be fine, ….5W-20, 30, or 10W- whatever …..

Pat

@harmonyards, do you know what this switch is for under the k4 tender?

@Casper posted:

@harmonyards, do you know what this switch is for under the k4 tender?

No picture buddy, ….

Pat

@harmonyards posted:

No picture buddy, ….

Pat

Don't tinker with it, that's the AD-20 that receives the IR serial data signal from the wireless drawbar, it also controls the backup light and coupler.

@gunrunnerjohn posted:

Don't tinker with it, that's the AD-20 that receives the IR serial data signal from the wireless drawbar, it also controls the backup light and coupler.

What John says, ……leave it be,….

Pat

Thank you guys!

It looks to me that the TMCC K4.5s has a different pilot truck design than the Legacy K4s.  On the TMCC one, the pin for the locating arm is only held upright by spring tension placed between the top of the truck frame and the bottom of the locating arm.

Pat, I think you we’re right from the start, the spring needs stretched, or replaced.

If the hole is truly wallered out, which it seems hard to tell from this view…

Then since there is room on top of the truck, seems to me a thin piece of plate metal could be affixed with a narrower hole to limit the fore and aft movement. Of course a bushing is more elegant.

Something like this comes to mind for the bushing route (in the right diameter of course). https://www.amazon.com/Ruikarh...rtment/dp/B07XSJZVFP