How does one remove the flywheels off the motor of the athearn AC4400AC , (the big gold things?) , they look like they may unscrew but before I put the pliers to work I want to make sure!
They are press fit.
–Randy
With older BB Athearn’s, I could hold a flywheel in each hand, and twist and turn until it gave up.
Better to invest in a puller.
Mike.
So if I can’t get the flywheels off without a puller, what can I do to shim or put washers (plastic ot non conductive) on the main shaft to keep the motor from moving forward as it gains speed. The motor has about a 1/4" of free play and when the speed ramps up the complete shaft , flywheels and armature move forward, which in turn make a heck of a noise, if I hold the flywheels back its quiet… I current just stuffed a little cotton from a Qtip in the front flywheel to make the front driveshaft push the shaft toward the back. (just a temp fix).
Where is it moving, is it pushing the whole drive shaft including the worm on top of the truck? It’s fairly common to install thrust washers on either side of the worm in each truck tower to keep the loco from bucking on grades.
–Randy
No, the worms on top of the truck are solid both front and back! As speed ramps up the complete flywheels, shaft and armature move foward … The worm gears and driveshafts stay in place, hence my temp fix of stuffing cotton at the end of the driveshaft on inside of the flywheel end ,where the driveshaft enters the flywheel.
If the motor shaft moves back and fourth more than 1/64” the motor is bad. Is it under warranty?
Mel
My Model Railroad
http://melvineperry.blogspot.com/
Bakersfield, California
I’m beginning to realize that aging is not for wimps.
CPBuff,
Do not try to remove flywheels by twisting them in any way. There is a very good chance that doing that you will completely destroy the motor. If your locomotive has motor used by Athearn for years, than this motor is made by Roco. With this motor, commutator (I do not know if you know which part is that – see one picture here, it is part A) is sitting very tight on motor shaft, as flywheels also, but iron core of motor rotor is not so tight on motor shaft.
#/media/File:Universal_motor_commutator.jpg){kind=link}
So, if you try in any way to twist the flywheels (especially by holding motor rotor with one hand), you will rotate also the collector, but not the iron core - all wires coming from rotor to collector will break, and motor is practically destroyed. I have done this with one of my motors, but damage was not important because I anyway replaced all Roco motors with coreless motors in my Roco locomotives.
If motor is under warranty, then return the whole locomotive for repair/replacement, because as Mel wrote, this is too much play of motor rotor. If not, then try to find someone more skilled, because first flywheels must be removed, and then motor completely dismantled and appropriate thrust washers (e.g. NWSL) installed – and that is not an easy task.
I don’t have any newer Athearn locomotives than the BB series and it is very easy to use a Mabuchi motor as a replacement.
The Athearn motor (bottom↑) has a 3.2mm shaft and the Mabuchi (and most can motors) have a 2mm shaft.
To me the Athearn motors are worthless so I just twist the flywheels off the shaft and replace them on the Mabuchi FK-280SA 14200 motor.
The flywheel fits a 3.2mm motor shaft and needs an adapter to mate the 2mm Mabuchi motor shaft. Evergreen #224 ⅛” OD tubing fits perfect in the flywheel and the ID fits the 2mm Mabuchi shaft perfect.
I’ve done this conversion to 8 Athearn diesels and everyone worked out perfect.
I haven’t dinged any motor by twisting off the flywheels. When the first flywheel comes off I grab the shaft with vicegrip pliers and remove the second flywheel.
Mel
My Model Railroad
http://melvin
Mel,
BB motors are different from Roco motors used in Athearn Genesis locomotives, they are pressfit, but very tightly, metal on metal. It is very hard to remove them. It can be done, but not by twisting them. At least that is my experience.
And yes, one of soultions is to replace the motor, as you explained.
Hrvoje
If they are moving back and forth that much, then the motor was perhaps built missing a thrust washer or two. Can’t add those without removing the flywheels, and if removing the flywheels will damage the motor - well, replacement is likely the only course of action.
One way to get press fit anything off is to heat it. If you don’t care about the motor but want to reuse the flywheels, a regular propane plumber’s torch will work, otherwise you need something smaller. And of course the universal couplings in the end are plastic and unless you can pull those out first, they will melt.
–Randy
Our two roundhouse level Athearn AC 4400 do not exhibit this defect.
Unless the warranty has expired then return for repair or replacement.
They do not unscrew. They are press fit onto the motor shaft.
I have a small bearing splitter and a modified C-clamp I use to remove them, but I am sure there are simpler ways to do it.
-Kevin
There is a simpler way to do it, although it may seem a bit brutal J. On following pictures a principle is shown. I have done it this way with many Roco motors, and did not damage any motor yet. For these pictures I used two motors, one without flywheels, and the other with flywheels.
To remove flywheels, I used a vise, two steel rods, a pin of slightly smaller diameter than motor shaft (shaft is 2 mm) and a hammer. Two steel rods should be tied together on both sides in some way. A bigger vise should be used than as shown on picture:
!https://up.picr.de/39879921wx.jpg?rand=1605542640
Before the above step, a brushes holders (two pieces) should be removed, because they can be damaged during flywheel removal.
Original motor, intact (flywheels are already removed).
!https://up.picr.de/39879917dk.jpg?rand=1605542640
Brushes holders partially removed:
!https://up.picr.de/39879918eb.jpg?rand=1605542640
Brushes holders removed:
!https://up.picr.de/39879919sk.jpg?rand=1605542640
Motor without brushes holder. Observe a tab on the left, which fixes the upper part of motor casing to the other part of motor casing. There are two tabs, one on each side. They have to be bent slightly, to be able to remove the upper part of motor casing.
That’s using a small diameter drift. If you also use a soft faced hammer, like a hard plastic or a dead blow mallet to cushion the low speed impacts you essentially duplicate use of a puller. Use of a drift is a long standing technique for achieving this result.
An alternative might be to use a spreader device on the inside faces of both flywheels. Push the one flywheel off against the other. No stress on the motor then.
Might only push one off but it also might just move both by enough to allow removal of each.
I concur with using Hrvoje’s method, using the correct diameter drift punch (like a nailset but with precise flat end and cylindrically-ground diameter) and either a small brass hammer or the deadblow type lastspikemike mentioned. But be sure you have careful padding everywhere below the area of work – two things will happen when the shaft comes out of the flywheel bore: the motor will drop suddenly and the flywheel will try to pull the drift sideways and roll with the rods off the vise. Trying to grab for one will accelerate the other… have soft padding all the way down, and predict strange ricochets… [;)]
I recommend that you measure the space from the flywheel face to the end of the shaft on each end – a plunge gage as previously described in the tapping thread would be just the tool for this, as (likely) would the drift you used for removal. You can lightly mark the shaft if you like.
As a suggestion for REinstallation, a subject not broached so far: I do not know if the flywheels are chamfered either side of the bore. You’ll want to use the same care reinstalling the flywheels straight on the shaft as you do taking them off, especially if you have to reinstall delicate parts of the motor before you seat the flywheels down all the way.
I’m tempted to have you clean up the very ends of the shaft so there are no burrs or mushrooming, and then ensure an entry chamfer on both flywheel bores. Gently “press-fit” the flywheels onto the shaft ends as far as you can go with hand pressure, then rest the ‘bottom’ flywheel on something like a leather pad on nearly-closed vise jaws (or the two rods), with a similar pad on top and a hex socket of nearly the OD of the flywheel. Tap on top of the socket with the brass/deadblow hammer until the flywheels are nearly to depth. Work very gently and very slowly, using an elastic ‘strike’ but little swinging force, just what’s necessary to get the flywheel to m
I wonder if these flywheels are installed by heat differential interference fit rather than pressed on. Brass and steel have radically different thermal coefficients of expansion (think hot water on a sealer jar).
A paint stripper type heat gun can be very useful for this type of situation because they use hot air and are frankly not very hot.
Heating the brass flywheels a bit might make extraction from the steel shaft easier.
For a drift I should think brass rod of correct diameter should work. Be careful not to over strike or you may bell the end of your drift and jam it into the hole.
For machining a slight chamfer into the entry side of the shaft hole in the flywheel try an ordinary countersink bit applied very briefly.
Here is a picture of the other side of a flywheel (from Athearn Genesis locomotive):
!https://up.picr.de/39884756pp.jpg
To install it back, I use a big vise and press gradually, but release after each small press and rotate a flywheel a bit, and repeat this procedure until finished.
Yes, a flywheel could be much easily removed if heat is applied. But heat source must be very precise, to avoid damage of plastic motor parts. I found very interesting discussion on German forum, you can read it here, use Google translator for english version. I do not have a torch, and frankly, I would hesitate to use this method for mentioned reason. But if I had a torch, I could try with one motor, I have them a lot, so destroying one is not an issue. So I would know, if this method would work without motor destruction.
But at least for install it back on the motor shaft, a “heat” method can be used. Then an ordinary oven can be used, if someone does not have a small torch at hand. Care is then required only not to burn your fingers [:D]
Hrvoje
I see no way the benefits of heat, which would be minimal, would ever overcome the unnecessary risk that would be added.
No heat! That is a bad idea.
-Kevin
I found NWSL instructions related to flywheel install:
!https://up.picr.de/34498143xc.jpg?rand=1605594703
!https://up.picr.de/34498145dx.jpg?rand=1605594703
I followed it each time and result was always satisfactory.
Hrvoje