Atlas C630 issue - male universal borked

[645diesel]

i noticed an issue with an Atlas C630 - it has progressively started to not perform well, to the point it would barely move and then stop but the motor was audibly turning. i took it apart and discovered the issue, the male universal that slides onto the motor shaft is no longer holding under friction; the motor just spins  

i was thinking a drop of blue loc-tite might do the trick, anyone ever have this issue and if so, how did you solve it?

[peteski]

The problem is most likely cracked coupling. If you carefully check it out you will see the crack.  Gluing it on might work, but it would be the best to replace it.  I think that Atlas has these in stock as spare part (because cracking was a common problem on these). 

[645diesel]

The problem is most likely cracked coupling. If you carefully check it out you will see the crack.  Gluing it on might work, but it would be the best to replace it.  I think that Atlas has these in stock as spare part (because cracking was a common problem on these).

looked all over for #540104 per the parts diagram, coming up empty handed.  i'll give the loc-tite a try and report back.

[C855B]

I had this exact issue two or three years ago, and, yes, it is cracked. Sadly, this is a characteristic of this design, and it's not just the C628/C630. I was able to purchase replacements at the time. FWIW, I also just looked for replacements at the Atlas site and one other parts vendor, and ran into the same dead-end as you did. Since there really is no substitute, you might drop them an e-mail and ask about status. My experience is they are good about answering e-mails.

I would be surprised if the Loctite idea worked, but ya' never know. Certainly no harm in trying.

[rrjim1]

I use loctite 620 it is a retaining compound and works great. HO slot car guys use loctite 620 and 680 to hold plastic pinion gears onto motor shafts.

[peteski]

I agree with Mike: email, or even call Atlas. They have excellent customer support. Maybe they'll scrounge a replacement "donut" for you.

[645diesel]

I agree with Mike: email, or even call Atlas. They have excellent customer support. Maybe they'll scrounge a replacement "donut" for you.

excellent, i like donuts...

mmm, donuts.

thank you for the suggestions, hope to get this out of the back shop and back on the road soon.

[randgust]

I ended up replacing both driveshafts with NWSL universals, steel shafting and couplings.  That works too.

On mine, both the male and female split on both ends.   The first time it blew was at Altoona pulling a train on the mammoth T-trak layout, where I found it just sitting there, dejectedly spinning away in about Run 6 with no movement.

NWSL parts require that you grind the male end into a "D" shape on the steel motor or driveshaft, so friction alone isn't what keeps it from slipping.  I just touch the edge of a dremel disk to do that.

[Steveruger45]

I did fix an IM sd40-2w that uses these donuts.  I changed the motor with flywheels for one from another loco with the more traditional hex holed flywheels and used sd50/60 drive universals.  Had to trim the hex end on the universal shafts a little.

[BCR 570]

NWSL also makes a replacement; I can look for the package and get you the part number tonight if needed.

Tim

[djconway]

Good to know on the NWSL replacements.  I have 5 of the big Alcos and have seen the same problem on Atlas' Fairbanks Morris locos.

[rdg5308]

Briggs Models also makes a replacement Universal set for the C630's.

[645diesel]

NWSL also makes a replacement; I can look for the package and get you the part number tonight if needed.

Tim

given i have two of these, i might as well "step up my game" as it appears to be a "when" not "if" situation on these... can you rustle up the part number, i looked at NWSL but it would be easy to get the incorrect one.  my eyes are going thru "the change" and these small parts are a slap in the face to my mortality 

[randgust]

I'm pretty sure the ones I used are NWSL 493-6:  https://nwsl.com/collections/shaft-couplings-driveline-universals/products/driveline-universal-connector-2-0mm-shaft-2-sockets-1-5mm-shaft-2-sockets

Steel shafting is 1.5mm:  https://nwsl.com/collections/shafting/products/shafting-1-5mm-od-x-6-l-2

I'm doing this without the benefit of the parts in front of me to doublecheck what I used, but those kits include the male, female, short ball, and the ball that has to be ground onto a shaft.  Critical check is the diameter of the motor shaft against the female 'cup' before you pull the trigger.   At least with this design you won't find the ball slipping on the shaft and you don't have to force it on to get sufficient friction.

If you look on my PRR D16 thread I'm using these for the tender drive as well, same material.   I had to order some more back in September as this project and the 630 repair pretty much tapped my supply out.

[Steveruger45]

Here is the link to the other thread discussing the various fixes with some nice details.
https://www.therailwire.net/forum/index.php?topic=50376.msg678643#msg678643