Discussion:
Drive Motor doesn't run

The hydraulics come on, so raise/lower/tilt work fine but when I throttle forward or reverse, I can hear (and see) the contactors pull in, but the drive motor does little more than an occasional twitch???

Any thoughts? This is an older machine, so no circuit boards, it seems to just have two contactors for fwd and reverse and a big honkin old SCR... and of course the motor. Not a lot to go wrong, I'd think!

Also, anyone know where I could find a manual for this machine? It would be nice to know if I'm putting the right oil in there
  • Posted 5 Aug 2014 15:33
  • By rob_c
  • joined 5 Aug'14 - 9 messages
  • Pennsylvania, United States
Showing items 21 - 22 of 22 results.
this truck have the cableform contactors on it?

try this trick and see if it just needs a new contactor kit
jack the drive wheel(s) off the floor
activate the drive in either direction and then wiggle the direction contactor that is pulled in and see if it takes off running. These contactors were well known for failing even though they did look ok and appeared to pull in. The armature of the contactor can get worn and hang/bind up.

I would also check the accelerator pot with a vom and make sure it has full range.
And of course double check the motor brushes, grab the leads and pull them out a bit and let them pop back in place, this will tell you if they are worn out too much or are hanging up in the brush holders. And like kevin says, look at the condition of the armature and make sure its not arc'd up and damaged. A good armature surface will have a smooth surface and be a chocolate brown color or shiny copper where the brushes ride.
  • Posted 5 Aug 2014 20:22
  • By swoop223
  • joined 23 Mar'12 - 3,696 messages
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
What condition do the motor Brush's look like worn out are they? How about the commutator that they ride on???
What is the serial number of the truck?
  • Posted 5 Aug 2014 15:56
  • By kevin_t
  • joined 2 Dec'10 - 1,301 messages
  • Pennsylvania, United States

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Fact of the week
The two internal cavities in our nose called nostrils function as separate organs. Each nostril has its own set of turbinates and olfactory receptors. The two independent organs work together through a mechanism called the nasal cycle, where one nostril is dominant for air intake while the other rests and is better at detecting scents.