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Rebuilding an MDC Shay

Russ Norris
 

I panicked a couple of weeks ago.  While installing a decoder in my DC powered David Hoffman Shay, I managed to dislodge the rear truck.  While working on that problem I accidently popped off the piston assembly.  In my attempts to repair that problem, one of the outside universals fell apart.  It took a couple of weeks of patient study of the manual (available online) and tinkering with the mechanics, but I finally got everything back together -- except that the external pistons and gears no longer operated.  It was hard to see the problem because the connection between the wheels and the external mechanism is hidden behind the truck side frame.  I applied DC to see if I could isolate the problem, but everything moved so fast even at low power that it was hard to adjust. So I went ahead and connected the digital decoder.  What a difference!  I can make the wheels barely rotate, and it was easy to find and fix the problem.  Here is a You Tube link to a video of the Shay on its side so you can see the pistons operated.  Very quiet and smooth, except for a little wobble where the gears connect to the rear truck.  I will take care of that.  Can't wait to send pictures of it operating on the layout.

https://youtu.be/-XUWtb3KztM

--
Russ Norris, MMR
Cape Cod, Massachusetts
http://blacklogvalleyrailroad.blogspot.com/

Robert Bell
 

VERY nice!  What motor and decoder did you use?

Rob Bell
Waynesville, NC

Russ Norris
 

David Hoffman replaced the motor that came with the original MDC kit and replaced it with a more powerful can motor.  I will take another look, but I don't think there is any writing on it.  On the other hand, David sold all his stock to Kevin Weisman, who now handles replacement parts.  You might check with him.  As for the decoder, it's a small Digitrax mobile decoder.  There's not a lot of room in this little Shay for a decoder and speaker, so I decided to go with a non-sound decoder.  I can always upgrade later.

On Thu, Oct 10, 2019 at 7:15 AM Robert Bell via Groups.Io <ionhoss=yahoo.com@groups.io> wrote:
VERY nice!  What motor and decoder did you use?

Rob Bell
Waynesville, NC


--
Russ Norris, MMR
Cape Cod, Massachusetts
http://blacklogvalleyrailroad.blogspot.com/

Mark Kasprowicz
 

Do you mean Kieth Wiseman - he's the spares man? But there are some excellent six pole (yes six) motors available on Ebay at present. 15mm square the top speed at 12v is 6500 revs and they have excellent torque. Only a couple of bucks too!. Worth a look.

Mark K

Keith Wiseman
 

Looks like it has a split gear on one of the rear truck axles, hence the jump about every wheel revolution. We have replacement drive wheel axle gears available.
 
 
Thanks,

Keith Wiseman
Wiseman Model Services Inc.
898 Blacks Cross Road
Paris KY 40361
859-484-9573
kwiseman@...
www.wisemanmodelservices.com

Russ Norris
 

Thanks Keith.  You may be right about the split gear, but my first guess is the rear jack shaft universal.  It came apart when I was working on the external gear train and it was a bear to reassemble.  I noticed that it looked lopsided when I reinstalled it.   Actually I think the main problem is the worm gears that transfer motion from the drive wheels to the external drive train.  I keep fiddling with the trucks trying to get the gears to mesh.  Sometimes the external gear train works but moving the trucks stops it.  Or it works okay in forward but not in reverse.  It's just a long process of fiddling with the mechanism.

Russ

On Thu, Oct 10, 2019, 3:37 PM Keith Wiseman <kwiseman@...> wrote:
Looks like it has a split gear on one of the rear truck axles, hence the jump about every wheel revolution. We have replacement drive wheel axle gears available.
 
 
Thanks,

Keith Wiseman
Wiseman Model Services Inc.
898 Blacks Cross Road
Paris KY 40361
859-484-9573
kwiseman@...
www.wisemanmodelservices.com


--
Russ Norris, MMR
Cape Cod, Massachusetts
http://blacklogvalleyrailroad.blogspot.com/

Robert Bell
 

Mark & all:
I "offered" $3.50 per pair (I ordered 3 pair) of those 15mm square motors and they accepted.  Shipping from China was only about 2-weeks.  Great little motors for $1.75 each!

Rob Bell 
Waynesville , NC

captaindavekrembs
 

On all of the MDC Shays I built or rebuilt got new axle gears. The originals shrink with age and crack.The NWSL replacements had a better tooth angle also.

Russ Norris
 

Thanks for the tip, Dave.


On Sun, Oct 13, 2019, 1:43 PM captaindavekrembs via Groups.Io <captaindavekrembs=yahoo.com@groups.io> wrote:
On all of the MDC Shays I built or rebuilt got new axle gears. The originals shrink with age and crack.The NWSL replacements had a better tooth angle also.


--
Russ Norris, MMR
Cape Cod, Massachusetts
http://blacklogvalleyrailroad.blogspot.com/