Electric motor runs but wheels do not move

[VCC3782]

I have a 2003 EZGO electric, series motor. Cart was running fine for 6 holes. From a dead stop, I hit the power pedal hard and cart started forward, then came to a halt. It almost felt like something popped after moving forward a few feet. Now it will not move in forward or reverse. Reverse buzzer works ok. Voltage currently reads 38 volts with digital voltmeter. I have an analog "state of charge" gage installed, and it shows the voltage is drawing down when power pedal is pushed. Gage pops back to normal voltage when pedal is released.

Could there be a shear pin in the drive train that sheared on me? Or, is this something that would happen when the brushes go bad? Any other ideas I can pursue before having someone come to look at it?

Thanks

[dougmcp]

Does the motor still run?
If so, chances are you stripped the spline at the rear brake drum/axle connection.
Put the cart on jack stands and run the cart (NOT FAST), if the wheels turn, that's probably your trouble.
You can also do this on the ground by removing the dust cap, pressing the throttle and watch the axle spin inside the brake drum center.
If you need parts (drums and axles) be sure to get OEM parts as the Chinese knock offs have a bad reputation.
The torque setting on the castle nut when you reassemble is 90# to 140#, anything less will cause it to happen again.

[VCC3782]

Thanks for your quick response, dougmcp. I did what you suggested. The wheels do turn. I lowered the cart and when I applied power it did move forward . However, when I put the brakes on with the power still applied, the cart stopped and I heard a muffled grinding sound from the rear wheel area. Unable to determine if it is the right side or left side.
Tomorrow I'll try to localized the source. I'm not a "real mechanic" but do most of the work on my cart. Two years ago I replaced the stock motor with a 2 speed, so repairs don't scare me totally. However, I don't have a lot of special tools, or expertise working with brakes, axles and bearings. Would you suggest I tackle this, or get a pro to do the work?

Thanks,

VCC3782

[dougmcp]

That's exactly what a stripped drum spline sounds like and it's rather common on Ezgo carts.
It's a pretty simple job to do, the hardest part is removing and re-torquing the castle nut.
I think I also have a portion of the service manual for that section to help you when you're ready.

BTW welcome to the forum, you'll find it to be a good place for info on your cart.

[VCC3782]

Thanks again for the additional info. I have the appropriate portion of the service manual myself, and found much the same from an online vendor of brake drums. I will do further testing to make sure the brake assembly spline is shot, and which one is the problem. Then, I'll go down to the local EZGO dealer to get a genuine EZGO part. I'll let you know when all is complete.

[dougmcp]

Good luck with the repair!
Let us know how it all turns out.

[VCC3782]

Well, now I do not think the problem is with either wheel brake assemble spline connection to axle. I removed both rear wheels, took off the dust caps, then replaced the rear wheels and removed the jack stands. When I apply very light power the cart will move. However, when I apply more power something in the drive train starts slipping and the cart stops moving. There is a muffled light rapid thumping sound coming from the motor/axle area. This is on a level concrete floor. The motor seems to rev up OK, even with the slipping, but very little power is transferred to the wheels. I can see the nut/cotter pin on both sides, and they turn the same as the wheels. No wheel movement, no nut/cotter pin turning. The more I press on the power pedal, the more thumping/rumbling sound I hear. By the way, when power is applied gradually the rear wheels seem to run at normal speed. However, I can not get any speed, other than a crawl, with weight on the wheels.

The motor is not a stock series motor. It is a 2 speed, shunted series motor I installed in early 2008. Never had a problem with it. I'll call the motor manufacturer Monday.

There is a spine connection between the motor and the differential. Could that be the problem?

There is no excessive heat on the motor, and no electrical smell during any of the testing I have done.

Thanks in advance!

[Michael Eddie]

Well, now I do not think the problem is with either wheel brake assemble spline connection to axle.

Hello vcc,,,I did not see in your post, did you remove everything in the way and just watch it? You must take it all apart and look for metal shavings, wear, etc. Remove the whole hub and check the axle end, replace what is needed. If everything looks good, tighten it down and move further. That step will require removing the motor and having a look, though something getting loose in there is far less likely.

[dougmcp]

99.5% of the time it is a bad axle/drum spline.
It's really rare but you could have a bad input shaft in the rear axle housing.
I doubt that the motor coupling is bad, but I would talk to your motor manufacturer and get his thoughts as well.

[VCC3782]

Thanks gentlemen,

I removed the dust covers from both rear wheels, giving me a direct visual on the hub nuts. With the wheels on and no dust covers I pressed the power pedal, looking at the hubs. The cart tries to move, but with light braking it does the muffled rumble while failing to roll forward. The hub nuts do not move if the wheels don't move. In other words, the power is applied, the wheels do not move, the hub nuts do not move, but the rumble sound is present. There is no slippage at the brake hub/axle spine. I wish there was. It would be an easy fix.

It is an EMP motor, and I will call them tomorrow. I'm not optimistic they will be willing/able to tell me much. Have a cart guy coming to look at it, as I really don't feel real comfortable tearing down the rear end myself.

I will let you know what the problem is when we find it.

If it ends up being something related to batteries and/or cables I would be surprised, but not totally. We'll see.

Thanks again

[dougmcp]

I hope you meant the dust covers as on the axle nit the hubcaps (wheel cover).
The disconnect is not seeing the hub nuts but the large castle nut with the cotter pin. If it rotates and the hubs stays stationary it's the spline.

To eliminate the batteries from question, put a digital voltmeter on the pack and hit the throttle, if the voltage drops any more than 15% look for a bad cable/connection/battery.

The guys at EMP are very helpful and honest, if they have a problem with one of their motors, they will make it right.

[VCC3782]

Dougmcp, I did remove the black plastic dust covers so I could see the axle nut/cotter pin for my troubleshooting.
Everyone has been very helpful. Thanks! I did give EMP a call, and they were helpful as well. It is hard for them to do much trouble shooting over the phone.

First, let me make my excuse up front for jumping to conclusions. The cart died, like it had been shot with my 357. Therefore, after checking the battery pack at 38+ volts under no load, and checking all the cable connections, I discounted the batteries and went for something in the drivetrain. Shame on me. One of the batteries would not take a load. I should have picked up on that when my inline analog state of charge meter took a dive when I applied power.

Anyhow, the cart is running fine now. I'll give it a real test Thursday for 18 holes. If it fails, I'll come back up on this forum. If it passes, I'll leave you alone.

Thanks again to all who contributed. My next purchase is a 6/12 volt load tester.

[dougmcp]

Glad to see you found the problem and learned a bunch about your cart at the same time.
The fix is certainly a lot less hassle and expense than the one you could have had.
I use a $15 voltmeter I installed in my cart that gives me a constant readout of how it is performing.
Here's the link for the meter: http://www.fcbelectronicsusa.com/ser...all-12v/Detail

Here's what it looks like:

[VCC3782]

Thanks, I ordered the suggested voltmeter (30-70 v). In the past I have always been able to find a bad battery by using my handheld voltmeter with alligator clips on the leads. If I suspected a battery problem, I would clip the leads to the terminals of 1 battery, run the cart up a hill to load it, and record the number. Then I would check the remaining 5 batteries the same way on the same hill. The bad one would drop to 2-4 volts, while the good ones would drop to about 5+ volts. I can still do this to locate the bad one, but the continuous readout of this digital onboard voltmeter will give me an early indication of trouble.

Thanks again.

[rocco]

How do you get the hub off looks it's attached all the way motor.

[Fishingdman]

My golf cart electric motor runs but cart won’t move either. Jacked rear end up and took off one wheel. The hub moves about 1/4” when pedal is pressed but it sounds lik the axle is just spinning in the rear end and wheels don’t move. Any suggestions. I am new to this forum and know little about golf carts

[blazzj]

How do I go about replacing the spline is there and manual