Maytronics drive motor 5521259-1 disassembly and repair

[wilkins]

Hi everyone, I have a Prowler 920, which uses the Maytronics drive motor 5521259-1. It is not working, and I've narrowed it down to the drive motor; it spins freely, gets stuck and becomes very hard to turn. I've seen a helpful video on how to get to the impeller bearings, but how on earth do you get the black plastic ring off the drive motor? As you can see in the picture, what appears to be the bearing is corroded, and you can see rust on the shaft. As you can see, I've tried to spin off what looks like a plastic nut but it won't budge. Does anyone know how to get this black plastic piece off?? TIA

 

[guinness]

Paging @JoyfulNoise, @Flying Tivo and @Apsuhead

Time for Maintenance of "Robotina" Maytronics S200

A little history, Robotina was bought 3 years ago from a seller on Ebay. He listed it as a Refurbished unit and got about 200 bucks savings from a new one. At first few months Robotina would live 1-3 days underwater. I got lazy and let her live 24/7/365 except for few minutes while wash down and...

www.troublefreepool.com

 

[JoyfulNoise]

You don’t. It’s a one shot deal. Designed that way so that the motor can’t unscrew itself when it turns CCW.

You can’t get replacements. Maytronics doesn’t allow it.

 

[wilkins]

Darn so there is no way to replace this bearing? It’s such an easy fix stopped by a bit of plastic.

 

[Flying Tivo]

Heat gun can be used to unglue the black part from the motor, but like Matt said, no use since there is no available part to replace it with. You can do it as an experiment and leave a trail in this post so future users can see available options.
Good luck!

 

[wireform]

If the motor turns ccw when looking at from the shaft end then that part will be a left hand thread if there's a thread under the plastic molded parts. The hex part in the picture looks to be molded together with the portion below it and will remove in one piece if there's thread which I think there should be.

 

[Jimrahbe]

WF,

I suspect that motor turns both CW and CCW depending on the direction the robot is going.

Jim R.

 

[JoyfulNoise]

The brass adapter on the end of the electric motor had two flats machined into it. The internal part of the black plastic union has a slot cut into it that is the same width as the space between its two flats. You screw the brass adapter with the motor into the plastic union and, when it bottoms out it “snaps” into a fixed positions. The plastic union “locks” onto the brass adapter. This enables the motor to spin CW or CCW and not unscrew itself if the treads get hung up on something.

You need to look at pictures of the motor without the plastic on it to see the flats in the brass and then look at the inside of the plastic union (it’s hard to do without bright lights) and then it will become clear at how it is assembled.

It’s a one-shot deal. No going back once the motor is screwed onto the plastic.

 

[JoyfulNoise]

The brass adaptor looks like this -



There are two flats machined into it. When you screw the brass adaptor into the black plastic coupler there’s a shallow “trench” that’s as wide as the Distance between those flats molded into the bottom of the plastic coupling. You can’t see it easily unless you shine a bright light into the gap between the motor and the plastic coupling. When you screw the motor into place it eventually bottoms out against the plastic and, as you turn it through one last thread pitch, the brass snaps into place in the plastic. It also forces that black o-ring into intimate contact with the plastic which seals the drive motor against water pressure. The whole thing is not meant to be taken apart.

In theory, one would replace the entire wheel drive motor assembly with a new one that contains both the electric motor and the black plastic hub. Maytronics repair shops will often show it listed as $100 but the item is always “Out of Stock”. After speaking to a few shops about it, I was discretely told that the item is NEVER for sale and that the manufacturer expects the entire motor assembly to be replaced, not individual components that make up the motor. And, for the most part, pool stores prefer that as it means simple repairs that don’t need anything more specialized than a #2 Phillips head screwdriver.

 

[wilkins]

Thanks for all the help guys! What a bummer. Was hoping this would be an easier fix. Apparently, it doesn't seal as good as they say it does, as this thing is only just over 2 years old. Only used for 7 months.

 

[JoyfulNoise]

Thanks for all the help guys! What a bummer. Was hoping this would be an easier fix. Apparently, it doesn't seal as good as they say it does, as this thing is only just over 2 years old. Only used for 7 months.

Wow! That's garbage. I got 5 years out of mine. But, like you, I took it apart when it failed and it was completely obvious to me how poorly designed the motor assembly is. Just the fact that they choose to use cheap, brushed DC motors instead of brushless motors is clue #1 that they could care less about longevity. Even the control board is left without being properly sealed against moisture. It costs less than pennies per board to do a conformal hydrophobic coating and they don't even do that. They are engineered for failure, not longevity.

It's the reason I switched back to a suction cleaner. I get basically the same cleaning performance from a cleaner that I can rebuild for less than $100 and one that I know will last 4 to 5 seasons before needing anything kind of intervention ... and it's half the price of the robots.

If you have to use a robotic cleaner, you can always look into AquaBot or Aiper to see if those are any better. Or, if your choice is a Dolphin, then I humbly suggest never leaving it in the pool for long periods of time but only using it as-needed. Water is what ultimately destroys them and their design is very poor against water.

 

[DogtownTX]

I'm having trouble with my Dolphin S300 and suspect a bad drive motor. Just curious how hard it is to turn when it's good/bad? Mine takes a pretty firm twist to rotate via the motor shaft, I certainly wouldn't say it spins freely. It doesn't require straining to turn, but definitely what I would call a firm twist. Thanks!

 

[JoyfulNoise]

I'm having trouble with my Dolphin S300 and suspect a bad drive motor. Just curious how hard it is to turn when it's good/bad? Mine takes a pretty firm twist to rotate via the motor shaft, I certainly wouldn't say it spins freely. It doesn't require straining to turn, but definitely what I would call a firm twist. Thanks!

It should turn smoothly and not require a “firm twist”.

When out of the water and up on blocks, can you run the unit? Does the impellar motor cycle through 3 different speeds and do the drive treads go forwards and backwards?

 

[DogtownTX]

I have it all broken down at the moment with a new (used) drive motor on the way. Once I get it all back together I'll see what it does. I'm hoping it goes back to at least working when turned on. What it did prior to the motor seemingly going bad is that it wouldn't respond to the power supply. If I turned off the power supply with the button, the robot would keep running. If I tried to start another cycle with the PS, it wouldn't start when 'powered on' unless I disconnected/reconnected the blue cable.

 

[DogtownTX]

Drive motor replaced and now robot is working normally again, or at least as normally as it was before.

I still have a problem with my power supply (I think) where the robot doesn't respond to it. I have to unplug the robot from the power supply then plug it back in to restart a cycle. If I hit the power button to kill a cycle, the PS turns off as expected but the robot continues the cycle.

 

[poolPROfoss]

For those with this model make sure you only do this or attempt it if your cleaner is no longer under warranty because if you do open the motor unit and remove anything, Actually just opening it does indeed void your warranty so I would recommend if you have a warranty on your unit do not open this motor unit , Contact mayotronics and go from there.

 

[Dcarlso1]

Thanks for all the help guys! What a bummer. Was hoping this would be an easier fix. Apparently, it doesn't seal as good as they say it does, as this thing is only just over 2 years old. Only used for 7 months.

Using the info in this thread, I pulled mine apart pretty easily with heat. The motor is in perfect shape, but the outer planetary gear carrier that is pressed on the output shaft is badly worn. The motor stops when it changes direction because the gears bind badly.

I’ve already replaced the other motor with one I ordered used from Israel, of all places. If I can’t find a way to repair the driver motor planetary gear, that’s it for me and Maytronics. I bought the unit new from Maytronics direct in early 2020.

 

[Dcarlso1]

BTW, water intrusion comes from a crushed o-ring under the plastic part of the assembly.

 

[JoyfulNoise]

Using the info in this thread, I pulled mine apart pretty easily with heat. The motor is in perfect shape, but the outer planetary gear carrier that is pressed on the output shaft is badly worn. The motor stops when it changes direction because the gears bind badly.

I’ve already replaced the other motor with one I ordered used from Israel, of all places. If I can’t find a way to repair the driver motor planetary gear, that’s it for me and Maytronics. I bought the unit new from Maytronics direct in early 2020.

BTW, water intrusion comes from a crushed o-ring under the plastic part of the assembly.

Any pictures worth posting?

 

[Dcarlso1]

I can think of a few interesting pictures to post -- the o-ring that's a flat as a pancake. I can take a picture of where that sits. Also, the planetary gear assembly -- it's very curious how the carrier wear pattern turns the circular profile of the lugs on the carrier into more of a football shape. I'll try to remember to snap a couple of pictures tomorrow.