# 302 brush bracket too tight?



## Old feller (Mar 30, 2012)

I know I was encouraged to sell these 302's as is, but I just can't do it w/o seeing what's wrong with them. Next thing I know is I have spent hours on a $15 to $25 loco getting it to as good a shape as possible.

This 1952 302's motor binds up.
Not the side rods, not hardened grease, not the smoke piston, not the side ways movement of the axle gear or smoke gear alignment with the motor shaft, not any arrangement of various numbers of thrust washers front or back, ( book shows 1 in front), not the oil slinger hitting the back bushing, and no scuffing evidence of the armature assembly rubbing on the field metal, or stuck brushes.

Runs fine f & r with the brush bracket screws slightly loosened. I seems that if I just release the compressing pressure between the bracket and the field the motor speeds up and runs fine. 
Also the armature never completely lines up with the field, when it runs fine f or r.

My next move is to shim the bracket out from the field.

I should have sold it as is or parted it out and actually make some $. But it's the challenge right?

Any thoughts about this problem greatly appreciated as usual.


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## flyernut (Oct 31, 2010)

Could be someone switched out the brush bracket assembly with another. I've had this problem before. Do you know if this is the original brush bracket assembly, and did it run before when the assembly was tight? Measure the length of the armature shaft against a armature that you know runs when assembled.Like I said, I've run into this problem before, and I changed out bracket assemblies until I found one that works.. This is straight from the American Flyer repair manual......"XA11077 armature assembly with 1/16 oil slinger can not be used XA9565-A brush bracket assembly manufactored before Oct.1949 unless you grind off 1/16" off the boss which the bearing sets into on the brush bracket assembly"...."XA9569 armature assembly can be used with XA-9565-A brush bracket assembly manufactured after Oct. 1949 providing you use 1/16" washer to take up end play".


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## mopac (Feb 24, 2011)

How many thrust washers are on each end of the armature? You need at least one on
each end. I have put too many on armature and it would bind. If you have more than one, remove excess and that would give you the clearance you need. This will only work
if you have more than one washer on each end. Otherwise refer to what flyernut says.

Let us know the outcome.

Someone may have lost an original washer and used one from around the house and it is too thick. That will cause the 
problem you describe.


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## T-Man (May 16, 2008)

The thrust washers are sold in different thicknesses 20 thousandth is average.

These engines will give you some experience. The price is attractive too!


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## Old feller (Mar 30, 2012)

Thanks y'all,
This is the first time I ever tested this loco, so I don't know if it ran right when I purchased it.
Thrust washers, it had two on the front, none in the back. Both were .020. I have tried many combos. The manual shows only one if front, didn't work either.
Re: being the wrong bracket, I read the same in the service manual. It is here that I may not understand what the problem is with the mismatched bracket and armature. It seems to me that the problem with the oil slinger on the armature would be that when the armature pressures back when the loco is in forward that the slinger would hit the rear bushing. There is always a gap when running forward or in reverse between the oil slinger and bushing, unless I fill it with washers.
I can manually back the armature up to where the bushing and oil slinger touch, so that tells me the armature shaft is not binding up in the bushing. 
I don't have alot of extra parts, (including brackets, unless I take other engines apart), to try, so trying to fix stuff makes it difficult. 
Funny, things keep telling me to sell as is.
Will try to work on it tonight, and will post any new info.
Thanks again.


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## dooper (Nov 9, 2015)

I have experienced the same problem, and have loosened the screws to make it run. I agree with Flyernut. I think you have an incorrect armature. Good luck.
Al


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## Old feller (Mar 30, 2012)

Spent a few hours tonight and: Because the problem goes away when the brush bracket is loosened and can move away from the field I tried shimming between the bracket and the field. Same problem. 
Found another brush bracket, same problem, took the armature out of the next 302 to be sold and put it in and same problem.
I saw a diagram that matched armatures and the locos that used them. But I have yet to see any info on brush bracket identification or describing any differences that might have helped.
So I put it all back together and will sell it as is, and move on the next 302 to be sold.

Thanks for the help.


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## mopac (Feb 24, 2011)

Strange problem for sure. Sounds like you can slide armature up and down some
when motor is assembled. How can it become bound when brush cap is tightened.
Shimming cap did not help. It all makes no sense to me. I understand flyernut and dooper have experienced this problem. Thank goodness I have not. So, does motor just not run with cap tight or does armature actually bind and you can not turn it with your fingers? You did what I would have done with swapping parts with another motor.
How could both 302 motors have the wrong armature and or wrong brush cap? Not likely.


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## T-Man (May 16, 2008)

I was recently working on a Lionel 50 gang car which may help. Both have worm gears butt his car only worked in the clockwise direction. Counter clockwise the motor rose and jammed with the gear. How did I notice this? I placed pressure on one side of the axle and it worked smooth. I placed a C clip on the axle between the gear and frame. The gear did not show signs of wear but it was the only way to limit side to side play without moving wheels on the axles.

If that does not work add a spacer on the bottom of the armature. The stress may be forcing the fields to touch the frame and prevent rotation. When you loosen the stress is gone.


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## Old feller (Mar 30, 2012)

Mopac, I think you got it, why this is frustrating.
The motor doesn't have to be running to feel the bind increase as the brush cap screws are tightened slowly and equally. Just by using finger pressure you can feel the binding increase. When the screws are firmed up to what I consider to be a normal tightness the armature is pretty hard to turn. This is with bare chassis, only smoke gear and drive axle and wheels.
T-man, I think I see what you are saying. I did try moving the drive axle left and right when running, to see if the alignment of the axle gear and armature made any difference. Made no difference.
I buttoned it up last night and was thinking to sell as is. With the caveat to say to the purchaser to run it with the cap screws kinda loose. Didn't really want to do that.
So, I came up with this idea:
If one of you "masters" would like to try your hand at diagnosing this problem child, I will be glad to send it to you. the problem can be experienced as I said with just the bare chassis and motor.
I just don't have a lot of parts to keep trying different combinations.
It probably is something that has been suggested already, but I missed the proper application of the solution. 
I could do what the fellow on eBay does, disassemble locos and sell the parts and make 3x the $. I really don't want to start going that way. I really like to keep these things together and running. Obviously most of us aren't in this hobby for the $.
Again if any of you want to see what you can do with this problem child let me know and I will send it to you.


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## flyernut (Oct 31, 2010)

oldfeller said:


> Mopac, I think you got it, why this is frustrating.
> The motor doesn't have to be running to feel the bind increase as the brush cap screws are tightened slowly and equally. Just by using finger pressure you can feel the binding increase. When the screws are firmed up to what I consider to be a normal tightness the armature is pretty hard to turn. This is with bare chassis, only smoke gear and drive axle and wheels.
> T-man, I think I see what you are saying. I did try moving the drive axle left and right when running, to see if the alignment of the axle gear and armature made any difference. Made no difference.
> I buttoned it up last night and was thinking to sell as is. With the caveat to say to the purchaser to run it with the cap screws kinda loose. Didn't really want to do that.
> ...


I'll give it a try..PM me and I'll send you my address. Just pay shipping both ways.


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## dooper (Nov 9, 2015)

Good for you flyernut! Please update us as to what you find, it will be a learning experience for all.


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## cramden (Oct 13, 2015)

As others have stated it sounds like there are miss-matched parts, the armature or the brush bracket, or both. A 1952 302 should have a Pre-Pullmor armature vs. a Pullmor armature. An easy way to distinguish the 2 is a Pullmore armature has a narrow gap between the armature poles, whereas the Pre-Pullmor armature has a much wider gap between poles. They both fit but the Pullmor one doesn't work well in the earlier non Pullmor engines. I'm sure flyernut will get it fixed if you choose to send it to him.


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## Old feller (Mar 30, 2012)

Cramdon,
Interesting. I just looked at the problem 302 and two others looked about the same. I tried using a micrometer while the motor was in the loco. Measured a little less than 0.12, a 21160 with pullmore tires looked to be about 0.09". Anyhow not sure I know what I am looking for.
Regarding the problem 302, while I was deciding to send it to Flyernut I decided to go through the E unit and get that cleaned up. I put it all together with the two brush bracket screws just ever so slightly loosened it ran like new. So I locktighted them in place and may just sell it "as is". Still would like to know what the problem is, if not wrong armature, then my best guess is something is slightly warped.
Thanks to all of you.


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## cramden (Oct 13, 2015)

oldfeller said:


> Cramdon,
> Interesting. I just looked at the problem 302 and two others looked about the same. I tried using a micrometer while the motor was in the loco. Measured a little less than 0.12, a 21160 with pullmore tires looked to be about 0.09". Anyhow not sure I know what I am looking for.
> Regarding the problem 302, while I was deciding to send it to Flyernut I decided to go through the E unit and get that cleaned up. I put it all together with the two brush bracket screws just ever so slightly loosened it ran like new. So I locktighted them in place and may just sell it "as is". Still would like to know what the problem is, if not wrong armature, then my best guess is something is slightly warped.
> Thanks to all of you.


Here is a picture showing the difference between the two armatures. Notice the wide gap between the poles on the non- pullmor vs. the narrow gap on the pullmor on the right.


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