# 302 pump gear



## ennisdavis (Dec 9, 2018)

I have two 302 ac engines with the same problem. the smoke pump gear is loose and it gauses the pump arm to hit the gear shaft and bind. Do they sell a tighter fitting gear or is the engine just worn out?


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## mopac (Feb 24, 2011)

I doubt your engine is just too worn out. One of our master builders will have an answer for you. Welcome to the forum. I have not experienced your problem so I do not have an
answer for you. Weird you have the problem on both locomotives.


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## mopac (Feb 24, 2011)

They do sell a new stud for the gear.
That might tighten it up enough to keep it from wobbling
enough to bind. Here is a link to an exploded diagram of your locos and part number for the stud. Maybe get a new gear also. Would be like new then. Either center hole in gear or the stud is too worn or both. Get both, can't cost much.


http://www.hobbysurplus.com/xviews/300s1pcHSS.asp

I think these locos will run forever. Maybe a parts change once in awhile. They will be running long after we are gone, LOL.


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## mopac (Feb 24, 2011)

Here is another thought. That shaft to the piston, Its called a piston lever, seems mine have an offset where it attaches to gear to keep it from hitting gear stud. Maybe try a little bending there so it doesn't hit gear stud.


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## flyernut (Oct 31, 2010)

Never seen this before. I have many engines that the smoke gear has a definite wobble, but it causes no problems..Make sure the smoke piston lever is on correctly. As MOPAC says, you might need a new smoke gear stud, it's called a "worm gear stud", part #PA10162, and the smoke gear is called a "worm gear", part #PA10671.


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## mopac (Feb 24, 2011)

Make sure the gear stud has not backed out any. Piston lever should not be binding
on the gear stud. Seems I remember the gear has a recessed area for the stud head.


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## cramden (Oct 13, 2015)

I haven't seen this problem either. One other thing to check is the shoulder stud that holds the piston arm to the gear. It's possible that it has become loose and needs to be tightened. It is the same as a threaded side rod stud with a small hex head. It might have backed out over time allowing too much play. The # is PA7421. Don't over tighten these, just snug them. They bottom out when tight.


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## race944t (Jan 5, 2016)

The screw holding the rod to the gear is shouldered. Tighten it up. The stud holding the smoke gear to the chassis is pressed in. Make sure it has not backed out some. The stud is a very tight fit with straight ribs. Support the back side and tap the stud firmly into the chassis. I've never seen the stud or inside of the gear wear out, but I suppose it is possible. Both are steel.


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