Rebuilding an old Athearn need advice.

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Chessie1973

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Nov 22, 2003
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I have an older Athearn F-7 that was an Ebay purchase and turns out that the motor is nearly shot.

She runs ok but runs extremely hot. We are talking painful to touch the motor hot.

I have repeatedly cleaned the commutator but every time I run it again it turns it black with some pretty thick crud like what often collects on the rails after running too many old cars with plastic wheels. The Loco does not have flywheels and seems to not have any wieghts either. Just a die cast frame, Motor, U-Joints and gearboxes. All the wieght is in the frame it seems.

I need some advice on how to best handle this. Please keep in mind I am not made of money and would have a hard time even scrounging up 30 dolars to buy a rebuild kit.

Is there anything I can do using the stock parts to help keep this old girl alive and pulling frieght? Or is she destinied to be a yard ornament?
 
do you have a amp meter and if so what kinda of current (amps) is it running .if you dont have a meter do you have another athearn unit that you could swap motors with to see if it runs hot also:)
 
I have one other Athearn but it is not the same type.

It is a GP 35 with flywheels and although it gets a little warm it runs no where near as hot as this one does.

I have a New F7 Coming via an Ebay auction that I may just replace this one with if possible but I don't know.

I am hoping to be able to salvage this one though, I hate to see such a well built little machine go to waste like this but I don't want to have a fire hazard running on my track either.

I may be able to scrounge up enough to get her a new motor possibly a little at a time but I am not sure. The local shop charges 25 dollars for a Mashima motor currently and that is a bit much to remotor an Old Athearn I got for 10 dollars online.

I am hoping I can remotor her or rebuild the current one but I am not sure if I have the patience to do a total strip down and rebuild of this one currently.

I may just concentrate on getting my Benchwork started for a while and worry about this unit later on when I have more money availible to me.
 
take motor out of loco and run on bench if it still gets hot than it's the motor if not you might have a drive train problem like old dry lub or a cracked gear,
 
Originally posted by Chessie1973


She runs ok but runs extremely hot. We are talking painful to touch the motor hot.

I have repeatedly cleaned the commutator but every time I run it again it turns it black with some pretty thick crud like what often collects on the rails after running too many old cars with plastic wheels. The Loco does not have flywheels and seems to not have any wieghts either. Just a die cast frame, Motor, U-Joints and gearboxes. All the wieght is in the frame it seems.
Click to expand...

The brushes on the motor are oiled soaked. That's because some one used household oil like 3 In 1 to oil the motor and it "crept" all over the place or they over oiled it.

Disconnect the universals at the motor. Remove the metal strip that run across the motor to the trucks. Pull straight up on the motor and the rubber mount will pop out of the frame.

Now look at the top and bottom of the motor. You'll see copper clips that hold the brushes in. Snap these off...be careful that the brush springs don't go "flying". Remove the brushes. Soak the brushes in some alcohol for about an hour and then let them air dry. While you are doing this clean the motor up real good again with some alcohol. Be sure to clean out the holes that the brushes fit in. You can take the whole motor apart if you want to it just snaps together. When the brushes are good and dry reassemble the motor, brushes, springs and clips. Put one tiny drop of a good oil on each end of the motor. Give it a dry run out of the loco and then reinstall it.

Now take the trucks off the loco. Pour some alcohol in a plastic bowl and "swish" the trucks around in it until "crud" quits coming out of them. Let them air dry. Then put a tiny drop of oil in each truck bearing. Lube the gears in each truck with a gear grease for model railroads.

Reassemble the whole drive train and loco and it should be OK.

Hope this helps:)
 
Well I completely dissasembled themotor and cleaned it with Alcohol thoroughly.

Not a lot af crud but more what looked like sludge buildup came from the gearboxes.

I ran motor separately for a good 15 minutes and it does indeed run cooler without the drive train attached but still runs fairly warm. A little warmer than my new Ather does but not alarmingly so.

Re assembled everything back on the chassis and connected power to the motor off track to let it run while I used tiny drops of 3 in 1 (sorry all I have at the moment and a little bit goes a long way) to lube the gears, universals and motor bearings. She sped up nicely once lubed but still a little noisier than normal athearns. She will run hot after a long run at full throttle for more then 5 to 10 minutes but to be honest I would expect it to be hot after than much voltage for so long.

I think he main problem is very bad brushes. Even after soaking and being scrubbed in alcohol they still seem to be oil soaked, I even lightly sanded the commutator while it was spinning with my fiberglass sanding pen and as soon as I took the pen away the commutator began to turn black, I did this repeatedly and it began to lessen so I think what the problem may be is that the brushes are fouled pretty badly causing the motor to draw too much current. My Multimeter needs new batteries or I would report the current draw of the loco.


I forgot to mention the primary thing that is getting hot is the permanent magnet now. Is there supposed to be any sort of lubricant IN the motor at all, I washed everything but this magnet when I tore down the motor.


I just finished an experiment comparing my new Athearn with this old Athearn.

Conclusion. Both units will run hot ir run for prolonged periods.

Method of testing. I set my Athearn DC throttle to 60 on the dial and let each run for 20 minutes towing my Walthers Track cleaning car behind them as dead wieght. Both motors felt the same to the touch. Hot but not painfully so. So apparently either the overheating problem was fixed by the tear down or I was just being overly paranoid about the heat generated by the motor. Either way Problem solved other than excessive noise.
 
Replacement motors are available from Athearn, the new motors use the same mounting system as the older ones. I bought one of the new narrow motors to replace a wide one for a scale width hood in my t-6 kitbash, the price was $14.95 with flywheels included. If your local hobby shop doesn't stock Athearn parts, or you have no local hobby shop, I think Athearn will mail order replacement parts.
 
Well this old girl is now in service as an F7 B Unit. Yeah I know silly huh.

But hey she purrs like a kitten. I only have one little problem with her unfortunately. It seems somewhere down the line the polarity has gotten reversed on it somehow. If I mount the gearbox assemblies correctly it will not go very far. If I put them in swapped front to back and back to front it will run perfectly.

This unfortunately makes it run backwards to all the other locomotive though which kills it being used as a MU unit unless I put a Dummy A unit in front of it.

The only thing I can figure it the worm gears may be the culprit of this but I am not sure.
 
Chessie, the only way the polarity on that loco can get reversed is at the trucks.

Check to see if you have maybe installed the rear truck in the head end and vice versa.....or.....if you had the wheels out of the trucks when cleaning it you may have reversed them when you put them back in.
 
Actually I know that the trucks got reversed. For some reason it wouldn't run right with them in correctly.

I got it working good now. I guess running it backwards to normal worked out the kinks in the gears and when I switched them back this time it works perfectly.

The old girl is running stronger than ever now. So now I have a second Athearn in good working order ready to pull frieght.

I love repairing old Locomotives that would otherwise be destined for the big landfill in the sky. akes me feel good to see them running on my track knowing that I made them work good again.

I did a MU last night of my GP 38 and this unit and they seem to make a pretty good team of power for pulling my train. Niether one seems to really try ot out pul the other. I had it sprting my F7 B Unit shell which looked a little strange behind that Geep but it worked out great. Nice even running although this one actually trys to get going a little before the Geep does.

I have a couple of F7 Athearn's coming via Ebay soon that I will probably use with this one. My mother has a B&O shell that came on this unit that she got these two for and I get whichever one she doesn't keep plus both shells. One is C&O and the other is in Pennsylvainia colors. I may just team this one up with the C&O in a consist for fun sometimes.

Thanks for all the help.
 
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