# Rebuild: Is it time?



## bruceme (Dec 10, 2008)

I purchased my Car used, I know it had one prior sets of lead batteries and I purchased it with a run-out set of led batteries. I think the conversion was done in ~2005. I've been driving the car as a daily commuter in deep puddles, snow and hot sun and I've put 20,000 miles on it myself (LiFePO4). The motor is a warp 9", 144v system, I commonly cruise at about 70A, and try not to go through 200A accelerating. When is it time to replace the commutators and rebuild?

-Bruce


----------



## EVfun (Mar 14, 2010)

I'd take a good look at the brushes and commutator and proceed based on what you find. New brushes and brush springs, along with a light stoning of the comm, might be more than you need at this point. I would take a look though, you don't want to wear brushes down to the rivets.


----------



## bruceme (Dec 10, 2008)

EVfun said:


> I'd take a good look at the brushes and commutator and proceed based on what you find. New brushes and brush springs, along with a light stoning of the comm, might be more than you need at this point. I would take a look though, you don't want to wear brushes down to the rivets.


I'm pretty skilled, but I've never done this before for this motor. Something I can do?


----------



## DIYguy (Sep 18, 2008)

bruceme said:


> I'm pretty skilled, but I've never done this before for this motor. Something I can do?


Absolutely. It's not difficult at all. In fact, removing the CE cover band, you can easily pull the springs back and remove the brushes. This will give you a better look at the commutator. U don't even need to pull the motor. All DC brush motors are made to allow brush service. . . as long as you can access this area of the motor! lol The appearance of the brushes can tell you a lot, if you research how to "read" what you see.

I tackled my first motor a couple years ago and although I did read up on it a bit. . it's about as straight fwd as can be. Much less complicated than ICE work. Just don't do something silly like put a puller on a cast fan and bust it. Major can address any finer details. .


----------



## Salty9 (Jul 13, 2009)

You might check the bearings. Replacement should be possible for an experienced DIYer. I would not attempt rewinding.


----------



## bruceme (Dec 10, 2008)

Salty9 said:


> You might check the bearings. Replacement should be possible for an experienced DIYer. I would not attempt rewinding.


What am I looking for? gravelly sound?


----------



## Salty9 (Jul 13, 2009)

bruceme said:


> What am I looking for? gravelly sound?


That's a good description. I have used a long screwdriver for sound transmission from the bearing housing but a cheap stethoscope from Harbor Freight would be safer.


----------



## piotrsko (Dec 9, 2007)

proper sealed bearings generally can have a life span of over 100K miles. Unless it is making bearing noises and doesn't spin freely, I wouldn't worry too much. OTOh if you like driving through deep puddles.... YMWV


----------



## bruceme (Dec 10, 2008)

Salty9 said:


> That's a good description. I have used a long screwdriver for sound transmission from the bearing housing but a cheap stethoscope from Harbor Freight would be safer.


Not sure, when I turn it over, I can hear something scraping. But that might be the brushes. It has a 6" aux pulley (for A/C compressor), if I pull that has hard as possible and let go, it does less than on revolution. I compared the force I put on the pulley to clicking my torque wrench, it's pretty low, but maybe 20"-lbs?


----------



## Salty9 (Jul 13, 2009)

Were you having problems with the vehicle or is this just preventive maintenance service?


----------



## DIYguy (Sep 18, 2008)

bruceme said:


> What am I looking for? gravelly sound?


When it comes to predicting bearing life and failure, it's pretty tough without vibration analysis and even then you need to build a history or profile to see trends in the machines characteristics. I would say, don't look for trouble. You will know a bearing problem when it actually happens. . . it's not like it's going to growl at you for 6 or 8 months. When it gets to that point, it usually gets worse real fast. 
On the other hand, if you actually disassemble the motor, just change the bearings. It's a no brainer. They cost nothing in the big picture.


----------



## piotrsko (Dec 9, 2007)

if you change bearings MAKE SURE they are the exact part number preferably by the same manufacturer, because cheap bearings with lousy grease and leaky seals are everywhere.


----------

