Kindernay maintenance.

[TPEHAK]

I am afraid to destroy it doing so because if another drive-train will fail Kindernay is the only option I have (besides the oil leaks it just works). Also depending on the ratchet mechanism grease actually can make it stop working or make it works worst or can cause shearing and destroying the ratchet mechanism parts due to not complete engagement (because of the ratchet mechanism parts can stick with grease, that's why you do not put grease in the regular rear wheel hub ratchet, just some oil). It would be nice to figure out how to disassemble Kindernay VII and maybe there is a way to replace the seals. Maybe it is something simple as putting a fresh O-ring. Kindernay should release gearhub disassembly manual.

 

[scrambler]

Have you tried contacting them top ask them that?

 

[TPEHAK]

I have not contacted them.

 

[Tom@WashDC]

I have not contacted them.

Pretty sure they are out of business. Went bankrupt a while back

 

[TPEHAK]

I emailed them and here is the automatically generated response

I emailed on [email protected], will see if they will respond. Meanwhile the trail.camp is not English speaking website.

 

[TPEHAK]

I received response!

thank you for your message and interest in Kindernay products and/or service.

The amount of oil to be used with the VII has been reduced to minimum, or approx. 5ml, but that's been done nearly two years ago already.

Kindernay did all service inhouse and never shared instructions or info how to exactly repair oil leakage. There are information in some Kindernay owners groups, from people which disassembled the VII hubs. Opening the hubs without causing damage is quite a challenge or requieres special tooling, therefor we do not recomment doing it, if not familiar how to. But in the actual situation without service centers, we understand that you might look into it further.
Be advised, to open the hub, you need to clamp the hub body and open the lid. Because the hub tends to set apart, the bode should be clamped with driveside down and putting force onto the lid upwards! The only points to put pressure on are the extended brake supports the lid has. It is crucial to apply this pressure eavenly across the hub (that normally requires special tooling already). The lid has a tight fit with an O-ring, therefor it snaps open, when it opens, otherwise its sealed quite well.
From the minimum information I have about the seals that could cause the leakage, these should be regular available parts, unfortunately I don't have measurements.

But before dealing with opening and replacement, due to the high oil level, even with undamaged seals, the hub could leak. Set up an oilchange and reduce the amount of oil significantly, or let it pour completely, the residue is still enough for the hub to run smooth (maby little louder).
Future oilchanges would only be pouring possible amounts of old oil and then fill with 2-3ml and run it with this amount.

the trail.camp Team

So, it needs only 5 ml of oil according to the distributor.

 

[scrambler]

Interesting info and worth a try...

 

[TPEHAK]

Welp, My Kindernay VII is finally broken. I did 30 mph in light uphill on my Bafang m620 with 3000W Innotrace controller, everything was fine and then all of a sudden quite loud inconsistent clicking sound with resistance spots. I was thinking something happened with the Bafang m620. But after inspection I realized the source of the issue is the gear hub. I was able to get home, inspected thoroughly and found the rear wheel locks when I rotate it backward. It also can lock rotating forward but if I put enough force it can overcome the resistance spot. Changing gears does not change the behavior.

Well, now I have no choice but purchase 3x3 nine hub, this is basically the only option I have for 3000W motor.

It also will be interesting to try to open the gear hub and see what is going on inside.

The gear hub did not experience excessive torque because of I used biggest chainring and smallest cog.

I also have Kindernay XIV on my other e-bike but I am not planning to pare it with 3000W motor, that thing is too nice to destroy it.

And for the record I used Red Line D4 automatic transmission fluid in this gear hub. I filled it with 40 ml about a year ago, then I filled it with 20ml recently and now the gear hub is malfunctioning.

 

[Tom@WashDC]

Sorry to hear its busted. That sucks

 

[TPEHAK]

I might be able to fix it. I opened the case and I see nothing disastrous yet.

Here is how to open the gear hub.

Clamp the brake rotor to a table and twist the shell to expose the case tabs. You might need a grip tool but it might be possible to do with bare hands.

Find some thick plywood and long M5 screws with washers. Drill 6 holes in the plywood to match the brake rotor mounting holes pattern. Cut some plywood spacers with equal width.

Assemble the gear hub on the plywood like this

Start tightening the M5 screws gradually. Eventually the lead will pop out of the case (there is a machined groove with a bump you need to overcome to pull the lead off)

The rest comes apart without special tools

The bearings feel quite rough, but they do not have free play. I opened the bearings seals and found some metal shavings inside. The grease was washed out with oil. Since the bearings do not have free play I cleaned them with high pressure water jet, dried with compressed air and packed with grease, after this the bearings feel good.

The leaks can not be fixed. The seals mating with the rotating parts made out of hard rubber material and they rubbed grooves in the mating metal parts. You can not repair leaks simply replacing the seals, you also need to replace the metal parts with the grooves those seals rubbed in those parts.

I found some metal balls felt out of the assembly and I am not sure were those supposed to be. That would be helpful if Kindernay would release assembly diagram so see where the parts go.

The gear hub is certainly serviceable, just make sure you take pictures of the process to assemble it back in correct order and keep the parts organized and clean.

 

[TPEHAK]

This is how far I was able to disassemble it and stuck. It looks like there is a plastic ring sitting deep in the bore needs to be extracted next to proceed with disassembly but I do not know how to extract it. It has some slots, maybe it needs a special tool to grab those slots, maybe rotate the part a pull it out but I was not able to move or rotate that plastic part.

I also feel like the problem is still inside because of all the extracted parts look good so far and the mechanism still binds here and there when I rotate it.

 

[TPEHAK]

By the way all the custom plastic parts in this gearbox are 3D printed parts. For instance this black part looks like FDM 3D printed part, probably nylon

This white part and other white plastic parts look like SLS 3D printed nylon

 

[TPEHAK]

Alright, I figured it out. You need to attach the cog, rest it on two pieces of plywood, put an appropriate diameter socket on top of the shaft flange (I used 11/16" hex socket, it fits perfectly) and lightly tap it with a rubber mallet or you actually can just press it with bare hand (it is slide fit interface). Make sure you hold the bottom portion to prevent the parts dropping down. After this the rest of the internals just falls apart without special tools.

 

[TPEHAK]

I already see the sun gear is busted. Some teeth are sheared. Maybe Kindernay or whoever purchased their assets after their bancrubcy can sell those gears as spare parts? A good gear hub design should be with easy to replace gears and gears should be sold as consumables. Planet gears look good though. Other parts look good too. Only sun gears and ring gears have excessive wear. The sun gears have the most wear and one is busted.

 

[TPEHAK]

I have disassembled the gear hub completely. The last tricky part was to remove this plastic ring. You have to remove the planet gears and press a plastic tab down through the opening catching the plastic ring on the opposite side at the same time with a pick tool

The rest can be disassembled without special tools.

 

[TPEHAK]

Here are the parts need to be replaced (one sun gear and 2 ring gears). These are steel gears pressed on or in the aluminum parts. The steel gears have knurled surface on the mating face crushing into the aluminum material to grip it firmly.

Other gears have nearly zero wear and look like new. The only worn gears are the gears pressed in the aluminum parts. The loose gears have almost no wear. Maybe they did not harden those pressed gears for some reason?

I am not sure if it is possible to extract those gears from the aluminum parts without destroying the aluminum parts because of they are pressed in with crush ribs and cooling or heating the parts probably will not loose the grip. The gears also have no features to grab them. I guess the only way to repair the gear hub is to replace those assemblies as whole units which is probably expensive.