RXV Brake "Dragging" & smells

davidgenes

I have an 08 EzGo RXV golf cart that I have been having issues with. It has a dragging brake sound at certain speeds, and now it has started to smell like hot brakes after riding a little while.

One night in the rain, it started going slower and then really smelling like brakes - and then smoke started rolling our from underneath. I ended up parking it in the ditch and walking home.

This has the Electric motor brake - not wheel / axel drum brakes, etc.

I got down to look at a few things and am a bit confused - there is no manual release lever on the brake assembly attached to the motor. It is just a smooth end, no place where it would even seem a handle could attach. I attached a picture. From manuals, reading, etc I believe there should be, correct??

Any suggestions on the brake drag issue? I was wondering about the solenoid, but it has never locked up on me - and it is still very drivable, coasts, etc, so it is not like the brakes are locked up (BTW, the brakes do work very well when applied).

Thanks for any help in clearing this stuff up for me!

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JohnnieB

I've never seen an RXV, nor a schematic for one either, but I have worked on electric drive systems that have electric brakes, which are also used for steering as well a stopping the 1 ton device.

Electric brakes come in two flavors, free-wheeling or Dead-man.
Without power applied, the free-wheeling type rolls and the dead-man type locks the wheels.

If the brakes on an RXV lock-up when a battery cable is disconnected, they are using the dead-man type.
Considering that lawyers ride herd on most engineering departments, I suspect the RXV's brakes are the dead-man type since all failures except having brake assembly fall off physically will cause cart to stop, never to move again until brakes are fixed.

The electric brake assembly works about like the clutch assemble in a stick shift car. Engine flywheel on one side, pressure plate on the other with a disk made of brake shoe/pad like material in the middle. The major differences being the output shaft is physically connected so it cannot rotate and the springs in the pressure plate are compressed by an electromagnet.

I suspect the brake pedal is connected to a potentiometer, rheostat or hall-effect device to proportionally apply more voltage to electromagnet in brake assembly as brake pedal is pushed further/harder.

If I am correct about the RXV having dead-man type electric brakes, the symptoms you state tell me that the brakes are not being fully released, so I would check for bad connections and or components in the Brake pedal circuit. IE: The electromagnet is not getting enough power to fully compress springs.

I'm guessing, but I think the voltage/current to the Brake electromagnet is controlled by the controller and the Brake pedal potentiometer (or whatever) is an input similar to the throttle input.

IIRC, The early RXV's had some brake issues (Came on unexpectedly) and there are some retrofits that had to be done.

Hope this helps.

davidgenes

Thanks JohnnieB for the clarification on how electronic brakes work!!

I just moments ago drove it about 6 blocks away and back. The several blocks it was going slower and slower and stinking bad like burnt brake shoes.

Once parked in the driveway, I looked and smoke was rolling out between the brake and the motor. It was almost impossible to be close enough to see because it stunk so bad.

Anyway, I attached a pic of the bottom of the brake - there seems to be some sort of fluid coming out? That is also the same spot the smoke was billowing out.

I am not sure where to start diagnosing this? Is there a voltage that can be checked at the brake connector to be sure it is getting what it should? Any specs on that?

Any help / suggestions on what to check would be greatly appreciated!

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davidgenes

More investigation = more info! :)

I had to leave the cart in the driveway last night because it stunk to much to pull it in the garage, so I just got around to looking at it this afternoon.

I went out to pull it in and it wouldn't move - brakes are locked. Well, actually, I was able to get it inside by putting the gas pedal clear to the floor - it would move, but very slowly and as soon as I let up on accelerator it would stop -- ABRUPTLY.

When I turn the key on or off, there is a click coming from the solenoid above the controller (with 2 large and 2 smaller poles), but the brakes stay locked.

If I flip the tow / run switch in Neutral (or any other key position), there is no click at all.

I guess I am suspecting the solenoid even though it is clicking (with key). Is there a way to test it? Check Voltage on some poles? Jump across a couple poles?

I do see that a couple wires going to it have been spliced, so I am guessing it has been replaced since the factory. I attached a pic for your viewing pleasure.

If you do suspect the solenoid, is that the right one (it is the only one I see)? Where do I get one? Any of the site sponsors carry these?

Please - any help would be appreciated - I am not sure what to do from here to diagnose the issue and the cart is dead in it's tracks!

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Jerj7907

I took my 09 RXV out riding our property looking for deer the other day and noticed a smell after riding at a slow speed for about 45 minutes. Shortly after the smell it shut down. I started to investigate and traced the smell to the resistor under the seat right behind the controller. I talked to my local golf cart dealer and the mechanic said it was a problem and suggested I add an electric fan on it to help cool it especially when moving slowly. He also stated to let it cool and it should be ok. Not sure what would happen if I would have forced it to keep going but it acted the same manner you describe. Would barely move when pedal was to the floor. Not sure where you can get a replacement resistor but from my experience it had a real bad smell and that could be your problem. Sorry can't offer more help but would like to know what your problem is when you do figure it out for future reference. Jeremy

davidgenes

My issue seems to be somewhat different as the smell was obviously coming from the brake itself (attached to end of motor).. There was a ton of smoke billowing out of it, so I am SURE that is where it was coming from.. That's not to say it isn't the resistor - I am not sure what that is even for - it is just that the smell and smoke was coming from the brake.

Now I am suspecting the solenoid less as I just checked voltage at the 2 pin connector that hooks directly to the brake. It has 0 volts in run with accelerator not pushed. When I push the accelerator, it jumps to 50 volts. I am guessing that is what it is supposed to do, so I am now suspecting it is something in the brake itself. Anyone agree / disagree??

Thanks!

Jerj7907

I would assume that is correct. Just an assumption though. The fact that you get power when pedal is applied and you visibly seen smoke. Never heard of your problem before. You might need to seek an authorized dealer to find the problem. The braking system is so different than the standard drum it takes more knowledge than I currently posses.

davidgenes

I pulled the brake off the back of the motor - it stinks bad and the metal is blue colored and paint "melted" off.. I figured this has probably got issues even if it isn't the problem (but I think it is) - - so I ordered a new one.

Any tips / tricks to replacing it - or just stick it up there and put the bolts in?

Do I need any sealer between it and the motor? There doesn't appear to be any on the old, but it was so hot I think it would be burned up anyway!

How about the old one? Can I take it apart safely - just to look at it? I started taking the bolts out and it seemed to have spring pressure that was going to make it fly apart if I pulled them out.

Thanks!

LuvMyTJ

What did the part cost when you replaced it? I assume it fixed your issues?

davidgenes

I got the EZGO 610065 from M&D Mower & Appliance (m-and-d.com) for $201.87 including shipping, etc.

It did fix the problem, but I still get a "rubbing" sound from that or the bearings perhaps - it is worse at low speed with partial throttle - or even coasting it seems. Haven't figured out what that is yet.

I did find that you put nothing between the brake and the motor housing - but do clean it up good.

Are you having a similiar problem?