A friend asked if I could look at a (non-running) brass Dash 9 that he had just acquired. I started by placing it on my test track which immediately revealed a dead short. So it looks like I’m going to have to take it apart to find what’s causing the short. But before fore I do that, there is a few things that need to be done. First things First Clear the bench top and make room for my silicone soldering mat. Having worked on a few of these I know there is going to be some Soldering /Disordering involved. These soft silicon mats available on Amazon for a few dollars really come in handy. It protects the cutting mat on my bench from accidentally getting melted when soldering/unsoldering parts, its soft enough that it won’t damage the loco, And has the added benefit of having molded in recessed pockets and raised outer edge which help keep small parts organized and tiny screws from rolling off the bench and disappearing into the “land of the Lost” Next is get the phone or a digital camera out and start taking pictures of it, top, bottom, front, back, and both sides, keep it close by and take plenty of pictures of each step as you go. Having those pictures will come in handy when it comes time to reassemble or for doing a writeup like I’m doing here. Note; Check to make sure the camera/phone is working properly, and that the pictures are coming out nice and clear each step of the way. (I just learned that I should have been doing this the hard way.) As such some of these pictures are Re-Creations Ok time to take it apart. Fortunately, the Brass Shells on these Dash-9’s were somewhat of a loose fit making it easy to separate the two. After removing the shell and setting it aside I did a visual inspection to make sure all of the clear plastic cover was there and that it was properly positioned over the chassis. (The clear plastic cover prevents the brass chassis from making contact with the brass body and shorting out). Once again placing the chassis on the test track revealed the dead short was still there. That rules out the brass shell coming in contact with the chassis as being the cause of the short. Next before removing the clear plastic shield use a sharpie and mark one corner of the chassis and the shield so you will know which end is which when you go to reassemble it. The plastic shield should lift straight up if it doesn’t don’t force it, Turn the chassis over and removed the 2 screws holding the fuel tank on, and gently wiggled the fuel tank side to side as you pulled it off the chassis. flip it back over and the plastic shield should just fall off in your hand. Get the soldering iron out and unsolder the motor wires from the chassis on each side. Look closely and you can see the plastic insulating cover on the chassis
Now gently wiggle and pull the frame halves straight apart keeping both ends even as you go. The trucks will fall free as it comes apart, Also watch for a small square of clear plastic shield to fall out from above the motor as it comers apart. Carefull don’t break the 4 spacer pins that connect and hold the chassis halves in place. Once apart gently pull the motor/flywheel/driveshaft assembly free of the frame and lower motor cradle. Once you have the motor driveshaft assembly out you can run test leads directly to the motor wires to test it. Be careful handling the motor/drive shaft assembly. Don’t drop it The slightest bend in the shafts will render the entire assembly useless. Note the square plastic shield that was above the motor The chassis halves pulled apart note the lack of bearings at the worm gear ends of the drive shafts The motor on this one is completely seized up and needs to be replaced. The roughly 24 year old Rogue Locomotive Works C40-9W commonly called the “Dash-9” had a Swiss made 0816 series 8-volt Faulhaber Motor which is no longer available, or is it? After spending some time searching the internet, I was unable to find a replacement Faulhaber motor at a reasonable price point. Fortunately, I know of another place to get a replacement motor and thanks to this years Black Friday Specials at AZL Direct they were on sale. Say what? You didn’t see them listed? Well that’s probably because you were looking for a Motor. The Buy one Get one Free Deal on the first generation of GP7’s is where you should be looking. Yup the First run of GP7’s, the 6202 - Chesapeake & Ohio, the 6203 - Nickel Plate Road, the 6204 – Pennsylvania, and the 6205 - Union Pacific, all used the same Faulhaber motor that was in the RLW Dash 9’s. The orignal Dash-9 Faulhaber Motor/Flywheel driveshaft assembly
Ok now that I have sourced new motor it needs to be removed from the GP7. Holding the fuel tank with one hand grab the top of the shell with the other and gently wiggle it side to side as you pull up on it to remove the shell. Next on the bottom side of the fuel tank between it and the truck on each end is a small tab that holds the 2 halves of the tank in place. Use a small screwdriver to pry the tab out just enough to unclip it allowing the fuel tank halves to slide apart freeing them from the chassis. Next slide the circuit board back and remove it from the chassis. Unscrew the Phillips screw on each end and gently pull the frame halves apart. The trucks will fall free as the chassis separates. Remove the motor/flywheel drive shaft assembly and set it aside. Next is an optional step. Reassemble the chassis in the opposite order putting everything back together including the circuit board fuel tank and finally the shell. The loco can now be used as a non-powered dummy loco. Here you can see the tabs on the ends of the fuel tank Placing the GP7 motor assembly next to the Dash 9 motor assembly you will quickly notice that while the motors themselves are identical, the flywheel/drive shaft /worm gear assembly on each end are not the same. So the longer dash 9 assemblies will have to be swapped onto the GP7 motor. Dash 9 Flywheel drive shaft assembly on top GP7 Flywheel assembly on bottom Having worked on a few of these older brass loco’s and haven swapped out the motors once before. I know that removing the flywheel/worm gear assemblies from both motors without damaging them can be a lot more difficult than it might seem. Drive assemblies like this are quite often put together using what’s called a “interference fit” In this case the interference fit, also known as a pressed fit is achieved by pressing the 1mm Diameter motor drive shaft into a smaller 0.99mm hole on the flywheel assembly. Additionally, some form of adhesive bonding agent like “Loctite” is often used to make sure the motor shaft does spin inside the flywheel during operation. Now before you attempt to remove the flywheel assembly from the Dash 9 motor measure the distance between the flywheel and the motor body at each end using micrometers, feeler gauges, or whatever method you have at your disposal. I Used a set of Feeler gauges for this. Write this info down so that you will know how far to press them onto the new motor. I was able to remove the flywheel/worm gear shafts from the Dash 9 motor by sliding the motor into a small Jeweler's Anvil that was clamped in my vice. After clampping a gear puller to the flywheel assembly, I held my soldering Iron against the flywheel heating it up. Then I tapped some small brass wedges in between the anvil and the gear puller forcing them apart. After giving the parts a chance to cool off I flipped the motor over and did the same to the other side. NOTE: adhesives commonly used in these types of assemblies such as CA Glues or Loctite 222 will release their hold if heated up to around 500* F. This much heat could easily destroy a motor so DO NOT do this to your GP7 motor. The Dash-9 motor was already dead so I was not worried about the heat damaging it. Removing the flywheel assembly from the GP 7 motor proved to be a bit more difficult. My first ended when I bent the push pin and broke the ears off my old puller . The smallest pin shaft on my new Walkera W010 Gear & Pinion Puller was too big to fit in the ends of the shafts. So I turned down a 3mm diameter piece of High Speed Tool Steel on my lathe to fit in the shaft ends. and used it in my new puller to push the motor shaft out of the Flywheel assembly. Take your time and make sure you are pulling/pushing the assembly straight off the motor’s shaft. Don’t use a cheap knock off gear puller. You don’t want to chance bending the motor shaft because your cheap puller gave way and broke halfway through the process. (hum I wonder how I learned this) The gear puller i used with the push pin i made sitting below the 5 that came with it and the GP7 motor with flywheel assemblies removed
Once you have both motors free you will notice that one end of the GP7 motor has a 1.5mm sleeve crimped onto one end. Depending on how the flywheel assemblies fit in the next steps this sleeve may need to be left intact, be turned down to a smaller diameter, or be completely removed. Now before you check to see if the dash-9 flywheels will fit on the GP7 motor use a -1mm (0-98mm) reamer in a pin vice to clear any residual bonding agent out of the holes in the flywheels. No power tools here simply slide the reamer in the hole and give it a couple twist by hand and pull it out, then blow any dust debris out of the hole. Rember your goal is to clean any residue from the bonding agent out of the hole. Not to enlarge it. The orignal Dash 9 Faulhaber motor on top and the one out of the GP7 with the crimped on sleeve on the bottom Try test fitting both flywheels on the smaller (1mm) side of the GP7 motor. Having already been pushed onto, then taken off the orignal motor shaft, the flywheels may just slide right on. If either one slides on easily with a loose fit and wiggles around at all you’re going to need the help of some Precision Machine tools. Using a set of Pin gauges to determine what the actual inside diameter of the loose hole is. Then turn the sleeved end of the GP7 motor down on a Lathe to 0.01 mm larger than the hole in the flywheel. If both are a nice tight fit as these were or are too tight to push on by hand you will want to completely remove the sleeve from the GP7 motor. The sleeve appears to have been crimped onto the shaft so it’s not going to just pull free. And since I still had my lathe out I decided to remove the sleeve by turning it down. After mounting the motor shaft in a 1mm collet I setup the steady rest to keep the motors from deflecting and used a micro carbide cutter to slowly turn down the sleeve. A couple pictures (recreations) of how I held the motor in my lathe to turn down the sleeve.
With the sleeve gone and the flywheel assemblies checked for proper fitment and alignment its time to press them onto the motor. First I checked my notes and got out the correct size feeler gauge I used to measure the distance between the motor and flywheel on the orignal assembly. Next I used a sewing needle to place a tiny drop of Loctite 222 inside the hole on the flywheel. Then pushed it onto the new motor using the feeler gauge between the two, to insure it was set at the proper distance. You may be tempted to just apply the Loctite to the motor shaft or to dip the end of the shaft into a drop of Loctite, Do Not Do It That Way. By placing the tiny drop inside the hole on the flywheel any excess will be forced into the hole on the flywheel as the motor shaft pushes in. Placing it on the motors shaft any excess will be pushed back along the motor shaft towards the motor where it could easily wick its way into the motor bearing effectively lockup up and destroying the motor when it sets up. With the first side on I powered up the motor at a slow speed to make sure it was spinning true then let it set 24 hours to allow the Loctite time to set up and fully cure. The next day before trying to press on the other flywheel assembly I setup my PanaVice with some alligator clip helping hands to hold the motor and the correct sized feeler gauges on each side of it so that I couldn’t push the 2nd flywheel on to far or mess-up the distance on the first side as I press it all together. Then After checking for proper alignment several times I added a tiny drop of Loctite 222 to the inside of the hole on the flywheel, cranked in the handle and pressed it all together. I really needed about 6 extra hands here, but I got it done. The Dash-9 parts with the GP7 motor before reassembly Again, I powered it up and made sure everything was in perfect alignment. Then let it set for a couple days before reassembling everything. Re assembling is fairly easy. Bend the brass contact strips on the motor out to the sides a little. Then slip the motor into the frame half so that it is resting on the lower motor mount with one contact tab sticking out the side aligning with where you unsoldered the orignal motor wire. Now put the other frame half on top aligning all 4 pins and slowly start pushing them together. once you have all 4 pins started slip the trucks in place then gently squeeze it together with the contact tabs sticking out opposite sides. While holding it together put the fuel tank on the bottom and reinstall the screws. Now slide that little square of clear plastic in between the top of the motor and the underside of the frame halves. Slide the motor assembly forward or backwards as needed so the flywheels do not come in contact on either end. Now bend the motor contact tabs in and solder them to frame halves on each side where the orignal wires were attached and cut any excess off. Place it on the track and give it a test run. first test with the GP7 motor Once your satisfied with its performance slip the clear plastic insulating cover over the top tucking the tabs down between the frame and the fuel tank. You may need to loosen the screws holding the tank on and wiggle it around a little to get the tabs in place. Re-tighten the screws and put the Shell back on. Just remember to pick it up by grabbing the sides of the fuel tank otherwise the shell might just lift off or worse the chassis could unexpectedly fall out.
Excellent job, Dave!! That's the kind of workmanship you get with the right tools and the artistry to use it. I'm glad you could get it running again.
