Postwar 3662 Milk Car repair

Definitely rewire the car. The brittle insulation on the wire will crack and crumble, and it's a short waiting to happen.

To test the coil and mechanism, apply power to the coil wires directly and observe the operation of the mechanism. It should work smoothly.

There is no need to oil the mechanism; it works fine without it. Without power, push the coil plunger in by hand and release it. The mechanism should operate smoothly and without binding.

Larry

Hi Larry,

so I rewired the milk car....and nothing. Same thing is going on. Melted out as much old solder as I could from the trucks and put brand new wires on both wires from the coil. It’s all clean inside, lightly cleaned with steel wool, made sure the wires weren’t touching any metal and shorting anything out, and by hand it sounded as if it would work perfect. Any other suggestions? Thanks. 
James

The wiring is simple, one accessory shoe to each end of the coil. With the car off the track try operating the coil with test leads. The tricky part of the 3662 is getting the proper lubrication in the dash pot.  The dash pot is the large piston and cylinder right next to the coil.  The Service Manual requires a oil molykote mixture.  But it has to be just right. You will get real good at disassembling the car before you get the dash pot work properly. 

David,

I disassembled this thing three times today alone. I got real good at it real fast. I already soldered the new wires on. As far as the piston spring and inside the coil, I don’t have molykote, though I do have graphite dust. Would that work? Do I apply it inside the dash pot, inside the coil, on the spring or piston itself? I’ll take any help I can get right now. Thanks. 

Hello James,

I'm by no means an expert, but I will offer this much:

Unlike it's predecessors, the 3662 uses non-magnetic milk cans. They are slightly different in size also, just enough to foul up everything if you attempt to use the wrong ones.

Also differing from the earlier versions, this car's action is not quite so "snappy". When functioning properly, its movement is much smoother and slower.

Hope this helps.

C.J.

James B posted:

David,

I disassembled this thing three times today alone. I got real good at it real fast. I already soldered the new wires on. As far as the piston spring and inside the coil, I don’t have molykote, though I do have graphite dust. Would that work? Do I apply it inside the dash pot, inside the coil, on the spring or piston itself? I’ll take any help I can get right now. Thanks. 

The molykote is applied inside the dash pot cylinder where the piston contacts to try and get an air tight seal.  It has to be soft enough to allow the piston  moves freely. The reconditions I have seen are to use the molykote based grease used for break in on new cam shafts. This should be available at a good auto parts store.  I then used a synthetic oil, like Lebelle’s medium weight oil, to thin the molykote to a creamy consistency. Once I finally get it right, the car works very well.

David,

im looking up molykote and I’ve found a few things online that says white lithium grease, which I have, can be used as a substitute. Any truth to this? What about graphite dust? Trying to figure out the best way to get this thing working again! 

Hello James

Since you have said you have taken the car apart 3 x in one day then a few more times  wont hurt . I say that because there maybe a few things going on at the same time . #1, when you have cracked wires always replace them . #2 , I would have it apart in my hand or on my bench and hook up the wires directly to the mechanism by it self , no other arms attached . If the plunger/coil work fine then go to step #3. #3 is where I check the two swing arms , the one where the milkman is attached and the one where the cans drop onto . Depending on its former life , one or both swing arms may be bent just enough to bind up .  This is what was binding my milk car up . I slightly bent the arms up , slightly being the key word , or else the milkman's head will hit the upper door jam . I found this out the hard way .  Note, make sure the milkman is pushed all the way down .  I actually had to trim a 1/16 of an inch off the bottom of my guy for him to sit properly .  You may also add a LITTLE oil/grease under the swing arms , there is a small tab that is on the arm that rides along the base of the car .   One other thing to look at is the  doors ,  do they swing open freely and spring back ?  If one or both doors don't swing easy the plunger is not strong enough to force it open .  I hope some of this advise helps in getting your car running right . 

I used regular Labelle 106 PFTE grease when I rebuilt the dashpot on my 3662, and it worked fine.

I did replace the cracked wires, which I was hoping would be the fix (maybe an old stranded wire was cracked and causing a short), but I still had the same result: I can hear the mechanism buzzing but a very weak buzz, but no movement on Mr. Milkman. I’m suspecting my problem is the plunger, it didn’t seem to be greased and I didn’t know it had to be lubricated. By hand, pushing the plunger with power to the car gets the milkman moving. I acquired this car in a box of trains as an add on, and it was boxed and it’s in great shape, clean and what would probably grade as excellent. It definitely seemed like it was taken care of before I got it. I’m almost afraid to bend the arms because the car seems to want to work. I’ll definitely try putting a tiny bit of oil on that little tab; I did notice it was dragging a little bit. As far as the plunger, I’m going to try the white lithium grease/oil mixture, and hope for better results. If that doesn’t work, what’s next? I appreciate all the help and info. 
James

I do not use white lithium on anything. In just a few years it can get so hard it has to be cut or chiseled out. Graphite and molybdenum disulfide are so different I could not guess if they are interchangeable. The LaBelle 106 sounded like a good alternative. 

First, no lithium; it is too thick.  Unless it is frozen in place, I would suspect that the dashpot is not the problem.  Does the mechanism move smoothly by hand?   As Larry mentioned earlier, power the mechanism directly from your transformer.  This will remove the UCS track and other miscellaneous items from the equation.  Keep in mind that the problem could be the chassis ground.  Connect one lead of your transformer direct to the mechanism and touch to other lead to the lug from the truck shoes.

David Johnston posted:

I do not use white lithium on anything. In just a few years it can get so hard it has to be cut or chiseled out. Graphite and molybdenum disulfide are so different I could not guess if they are interchangeable. The LaBelle 106 sounded like a good alternative. 

I agree with the white lithium hardening. It certainly does. I don't use it any longer either

Power the coil directly and observe the operation of the mechanism. If the mechanism moves freely when pushing the piston by hand, but not with the coil energized, you may have a bad coil.

Larry

Larry,

I was just messing around with this again and I powered the car by hand directly from the transformer, and there was still no juice. I’m wondering if your assumption of a bad coil is correct. When it’s powered on the UCS and I push the piston by hand, it’s buzzing and moves smoothly. What could cause a bad coil? Just the fact that it’s 70 years old? Everything else on the car is clean and it’s got new wiring. 

Based upon the number of times you have disassembled and reassembled this unit and replaced the shoe wiring make sure your coil wires have not gotten broken coming from the coil to its connection point.

If you have an ohmmeter, disconnect the coil wires and check for continuity through the coil. You should get a reading.  A reading of infinity would be an open coil.

Larry

Bob Hannon’s book says the coil should have 2.1 to. 2.2 ohms of resistance. That is not much resistance. Do not know the inductance, but it will must draw a lot of current. 

I don't know who Hannon is, but that number is somewhat off.

5-7 ohms shows a good coil.

This is Bob’s book.

Try a spray on teflon dry lube for sliding mech's from milk cars to gatemen shacks. (T-9 is great though pricy if it's still around, but I'm ready for another can ($18 at Grainger about 2004)... the cheaper autostore brands aren't awful) It will dry fast to a very very thin waxy looking coating; slick as Elvis 

Wet lubes can actually be too sticky for small parts. Breaking free of it's grip to slide at all can upset the balance of spring loadings etc.

 It won't migrate, plastic safe, people safe (T-9 at least) cleans of hands. It is a lube and deicer for airplane wings and flaps but works great with small stuff too.

Do you have a meter? A test light/probe? .  Start by insuring there is no contact from frame to either wire or coil terminal to chassis BY METER or TESTER. If that reads no continuity by whatever method you use, now measure the coil ohms. Checking for no continuity to frame ensures a true reading of the coil.

There will be an inner sleeve for the slug to slide on. It may be worn or even melted. Feel as it slides for evenness and hanging; the effect of a worn one is surprising. (most solinoids like T-9 here. It would often help me with nearly dead pinball coils last until new sleeves arrived, and extended the life of new)

Your own fingers should also be able to tell if that electromagnet (coil) has a good pull or not.

Coil wire is coated with a "paint" (epoxy mostly, sometimes lacquers though). The coating may crack, burn, be washed off/thin by loose solvent drops, etc...or wear through from vibration (there is a 60hz buzz every time it works, heard or not)  Depending on where/how it shorts inside decides if the pull is slightly or greatly weakened as a short basically removes X wire turns.  (More wire turns added =more pull).