Ancient LETRO three wheel pressure robot

Automatic pool cleaners, vacuum heads, pool covers,
decks, fencing, pool alarms and security ....
mknmike
Swimming Pool Superstar
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Posts: 221
Joined: Fri 02 Jul, 2021 21:00

Ancient LETRO three wheel pressure robot

Postby mknmike » Sat 28 May, 2022 09:47

In a few days I hope to add some pictures. Sorry I don’t have any good ones right now.

I replaced the spring with membrane in the piece that screws into the wall. It was about $17, and had been shooting lots of water bc the membrane had torn. I don’t know how this spring works, but I replaced it and have much less water loss there. Not much difference though.

The reason for posting is that the robot has been getting stuck in corners this year. I discovered that even after the above change, the side with one wheel still seems to move, but the side with multiple wheels does not. Then I saw that there is a metal geared shaft that runs from the one moving wheel to the side with multiple wheels. The front wheel that the metal shaft drives had its gears all stripped off the inside of the plastic wheel.

To resolve the problem I swapped the front stripped wheel with the rear wheel that appears to have never been used for its gears. Apparently the spring-loaded small center wheel that doesn’t touch the ground drives the rear wheel. The fix appears successful.

The only bummer is that I broke one of the three plastic screws that hold the wheels on. Since the spring loaded wheel seems to snap on pretty tightly, I left that one wheel with no plastic screw.

The robot seems so old that I don’t expect replacement parts to still be available, but I can probably find myself an acceptable replacement. The superglue attempt on the screw failed as soon as I tried to screw it in.

Oh… I noticed that the tail hose has a hole in the side near the end. Apparently it’s been whipping against the bottom of the pool for too long and the bulbs on the whip tail are worn down. So I will need to replace the tail soon. Maybe I can just cut it a little shorter.

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[img]https://uploads.tapatalk-cdn.com/20220528/3959f87d8c731f739dc75972f83ea82f.jpg[/img]
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mknmike
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 221
Joined: Fri 02 Jul, 2021 21:00

Ancient LETRO three wheel pressure robot

Postby mknmike » Sat 28 May, 2022 09:58

https://uploads.tapatalk-cdn.com/202205 ... 30ff2f.jpg

https://uploads.tapatalk-cdn.com/202205 ... 361acc.jpg

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[img]https://uploads.tapatalk-cdn.com/20220528/66ddda873111fe6346ddac36a330ff2f.jpg[/img]
[img]https://uploads.tapatalk-cdn.com/20220528/6b30944828163f01e650d9df3d361acc.jpg[/img]
[img]https://uploads.tapatalk-cdn.com/20220528/63c737fdd0bfa173de56faa4f26e50ed.jpg[/img]


This wheel looks like it could the the part I might need if I wear out the gears on the inside of my wheel I moved from the rear to the front. I guess if I wasn’t removing multiple screws to swap wheels I might not have broken a screw. https://www.walmart.com/ip/Pentair-Letr ... L/36739784


https://www.ebay.com/itm/202181043372


Edit: FOUND THEM! Wheels screws…

https://voomisupply.com/products/pentai ... %20Cooling
mknmike
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 221
Joined: Fri 02 Jul, 2021 21:00

Ancient LETRO three wheel pressure robot

Postby mknmike » Sat 10 Sep, 2022 15:02

Ok. Broke again. This time it is the turbine freezing up due to a bad bearing. Now I see the bad bearing was probably why the wheel gears got stripped.

Now it’s looking like I should replace all the wheels, turbine gear and certainly the turbine bearings. Sounding like a rebuild kit will make sense.

Will the MAKHOON kit on Amazon work? It says it’s for Polaris and the parts work for other setups but not the bag. It looks like they could all work for mine. Prime with free returns. Tempting for $120. I already ordered some bearings though. Prime and free returns on that $13 purchase too though.

MAKHOON Rebuild Repair Kit Replacement for Zodiac Polaris Automatic Pool Cleaner 280 (Not Compatible with Polaris 360 380) https://a.co/9lFHZAQ
mknmike
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 221
Joined: Fri 02 Jul, 2021 21:00

Re: Ancient LETRO three wheel pressure robot

Postby mknmike » Sun 11 Sep, 2022 08:10

Since the bad bearing is actively causing the wheels to bind up, grind gears on the wheels, and basically end up with a dirty pool floor, I called my local pool supply store to see if they had parts in stock (and for the current bromine cost). No beatings for a Letro in stock (and bromine is $449/50-lbs). So ordering what can arrive fastest from Amazon is worth a shot.

I’m starting to think that maybe I should have ordered what looks like a perfect match instead of what can arrive first though.

I ordered these: AOIT Turbine Bearing Replacement for Polaris Cleaner 180/280 C80 C-80 Pentair LL505G/ LX 5000G EC80(2) https://a.co/i9bKtYc

But the hole for the turbine shaft looks small on those, and these too…

Guardian Filtration Products G-TURBB-02 Turbine Bearing Replacement for lc80; llc8, EC80 https://a.co/jaT60u3

But those are also prime and free returns. I wonder if I should order a pair of those too.

These are the ones that look right though.

Swimables EC80 and C80 Bearing Replacement for Pentair and Polaris Pool Cleaners - Compatible with LL505G Replacement Parts, Letro Legend Pool Cleaner Parts, Polaris Cleaner - 100% Made in USA 2 Pack https://a.co/aqoMNEx

Notice the Letro on the description there too.
mknmike
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 221
Joined: Fri 02 Jul, 2021 21:00

Re: Ancient LETRO three wheel pressure robot

Postby mknmike » Sun 11 Sep, 2022 08:28

While covering my Letro pool robot, I should also mention this repair I also had to do this year. The housing is now spraying out some water, but the timer is still functional after simply adding some plastic bag material to the inside of the stripped gear to make it fit more tightly. https://www.poolhelpforum.com/viewtopic.php?t=47281
The circlip has since popped off and jammed the gears. So I should have probably thrown away the circlip that caused that problem, but I didn’t, and somehow it’s still hanging in there.

I just wanted to join in that thread.

I see there are far less expensive “back-up valve” options that look more like a cone. With such low prices on them, perhaps I should switch to one of them. The backup timer balance has become a very important part of the setup when the wheels are jammed. The tail hose on the robot can blow the junk off the bottom in each location and then the back up valve will move the robot somewhere else and repeat.
mknmike
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 221
Joined: Fri 02 Jul, 2021 21:00

Ancient LETRO three wheel pressure robot

Postby mknmike » Mon 12 Sep, 2022 17:24

The blue bearings fit, but we’re REALLY tight on the turbine shaft. I had to use an old bearing to press the new bearing down past the wheel portion. I don’t know if there was buildup there or if the turbine shaft is so old that the stainless shaft is worn where it easily slipped over the part that contacts the gears inside the wheel.

In any case, with my nice blue bearings. The turbine spins smoothly, and I put the two best wheels on the drive Wheels. (My temporary solution was actually holding up and the robot was working, but I was glad to get these new bearings in.)

Now I know that every once in a while the bearings need to be changed. Also, if your turbine is grinding wheel gears, there’s a good chance you’ve got bad bearings. Live and learn.

Next parts to replace:
- backup valve
- wheels
- bag
- rubber flap under bag
- tail hose

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