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I have a 6250 I'm fixin' up and the last detail is the front electromagnetic coupler. The thing opens easy-peasy but doesn't always shut. By applying my scientifically oriented analysis skills, I held it pointing straight at the ground and the knuckle simply would not close - jammed in the full open position. Tilt it back and point it at the sky, and it closes finer than frog's hair. Conclusion?

I thought it had a broken plunger spring, so out comes the knuckle rivet, the knuckle, a worn knuckle spring (the two arms of the spring are parallel), the plunger and the plunger spring. The plunger spring looks slightly compressed but definitely not broken. Checking the knuckle, I can see witness marks where the plunger hits the rear part of the knuckle. I gently filed the rear of the knuckle silky smooth, then I chucked up the plunger in my drill and smoothed off the business ends, adding just a wee bit of rounding to the small plunger edges. I didn't have a new plunger spring so I carefully stretched the old one just a bit. Reassembled everything, adding a new knuckle spring in the process, and it now works much better, but still is a little hard to push closed in the "straight at the sky" position - no lube of any kind was applied - I'm 100% certain a small drop of oil would make things silky smooth, but oiling a coupler just doesn't seem like a good idea..... 

I did not clinch the knuckle rivet at this point, hoping to hear back from one of ya'll who may have encountered and solved this problem previously. Watcha got?

Last edited by GeoPeg
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I specifically recommend against plain oil, that will cause you move issues than it solves!  Also, as WD-40 dries, it turns into a gummy mess, so that's the last thing I'd use.  I've gotten guns that have been "preserved" using WD-40, and once it solidifies it's like glue,   several had to be soaked for days in solvent to get them apart.

Use a truly dry lubricant like graphite and you will have much better luck.

Like I said everything mentioned works. Graphite would be my first choice. 

As for WD40 glueing things together, I have never had that happen. Maybe a reaction with something already in there like some adhesive.

Here is what is in there. If you are not as chemist then contact one and see if any of these ingredients will on their own result in parts seizing together.

Material Safety Data Sheet (MSDS) for WD-40 aerosol indicates the product is primarily petroleum-based, with the main ingredient being “solvent naptha, petroleum, medium aliphatic” (also known as Stoddard Solvent):

 

 

  • solvent naphtha petroleum, medium aliphatic, > 60%

 

  • petroleum base oil as paraffinic distillate, heavy, solvent-dewaxed (severe), 15% to 25%

 

  • corrosion inhibitor unregulated, 1% to 10%

 

  • wetting agent unregulated, 1% to 10%

 

  • fragrance unregulated, 0% to 1%

 

  • carbon dioxide, 2% to 3%

Pete

 

 

Now I am worried.  I put my postwar GG-1 trucks into a vacuum of WD-40 in the late 80's.  Still run very smooth.  How long does it take for the WD-40 to go bad?

Can you elaborate on what a vacuum of WD-40 means?

I ask because I've done some reading on rejuvenating Oilite bearings. The consensus seems to be to put the bearings in an oil bath and place the container in a vacuum chamber.
I'd have to look up the type of oil and how much vacuum.

aussteve posted:

Now I am worried.  I put my postwar GG-1 trucks into a vacuum of WD-40 in the late 80's.  Still run very smooth.  How long does it take for the WD-40 to go bad?

In a thousand years they will find your engine, put power to it and it will run. WD40 may evaporate as its mostly solvents but it won't gum up of its own accord. If it contacts paint, certain plastics, or adhesives it may disolve those adhesives allow them to run into tight places but its not the solvents that are gumming it up. The tolerances in a set of post war couplers along with lack of paint to dissolve precludes this happening for the OP or your trucks.

Pete

This is from the oilite website. 

"After extensive machining, bearings should be re-impregnated with appropriate / specified oils. Vacuumed impregnation is recommended. If bearings were not lubricated prior to machining and if cutting fluids were used, that medium must be removed prior to any impregnation of the oil selected for the application. Your authorized distributor can provide oils for re-impregnation after machining."

Many bearings available for postwar trains are "new old stock".   Since these may not have been stored well over the years there has been some oil depletion. Mr Burfle please keep us posted as to what you learn. I believe that it is a vacuum pressure inpregnation process, same as used on electrical equipment. The difference being on electrical equipment the vacuum is trying to remove moisture as well as air.  I assume that with too much vacuum the oil could be boiled out of the bearings too. 

If I may side-track this discussion back to the repair task, I sanded the back of the knuckle with #400 grit, then #600 grit emery paper, to a silky smooth finish, then stuck it all back together - worked great! Then a puff of graphite and it was like stabbing warm butter - best action I've ever felt in a coupler!

Then came the clinching of the rivet - one more bent rivet on my gigantic arbor press .... I finally just used my needle nose to flatten the end of a new rivet, worked great. I guess the purist in me decided to take a back seat to the practical repair guy.

Thanks for all the comments and suggestions. I will never know about the WD40 cuz I do not use it as a lubricant. That said, it does an outstanding job of refreshing disgusting, age-whitened side frames when applied and mopped up by a Q-tip!

On to the next new problem ... my new shoe hits the frog rivet on this one switch (an 1121) every single time, and of course when it does, the coupler fires! Starting a new thread ....

This is from the oilite website. 

"After extensive machining, bearings should be re-impregnated with appropriate / specified oils. Vacuumed impregnation is recommended. If bearings were not lubricated prior to machining and if cutting fluids were used, that medium must be removed prior to any impregnation of the oil selected for the application. Your authorized distributor can provide oils for re-impregnation after machining."

As I recall, there were also warnings about using the proper tools. For example, I think filing was a no-no. Improper machining would cause the pores to be obstructed.

I am not actively pursuing the recharging of Oilite bearings having decided it was impractical for me. Aussteve's post triggered the subject for me.

Thanks for all the comments and suggestions. I will never know about the WD40 cuz I do not use it as a lubricant. That said, it does an outstanding job of refreshing disgusting, age-whitened side frames when applied and mopped up by a Q-tip!

A clean, dry toothbrush works wonders too.

Put a bit of WD-40 or CRC 2-26 on the side frame, then spread it around with the dry toothbrush.
Afterwards the toothbrush can be washed out and used again.

Last edited by C W Burfle

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