Lift / FR motor water tightness

Had a look at a Lift motor that took water in last week. The shaft seal on the motor is a radial seal, one lip. It is not a classic seal, David told me it is custom made. I have seen some Parker seal similar to this. They were made from PTFE filled with graphite with the o-ring. If I remember correctly they are made for high shaft speed application to prevent wear on shaft. The o-ring prevent the seal to rotate in the bore.

On the Lift there is also the exact same seal fitted in the prop guard and an o’ring between the matting surface of the motor and prop guard.

If you remove the prop guard you will increase drasticly the chance of water intrusion. The tail cone Lift sell has the same seal. Any custom designed tail cone should integrate a radial seal otherwise you only rely on a single lip seal to do the job.

Managed to save this motor before it was too late, lucky…


What was the reason this lift motor had been leakin letting in water? Are the single lip seals inadequate, or had the prop guard been removed?

I’d like to improve the waterproofness of my 65161.

The O-ring sealing the front cap was worn.

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Any chance of a photo of where the o-ring sits? It didn’t look like there is a lip/recess for an o-ring on the propellor guard.

this is a lip seal

Thanks, I was also wondering about an o-ring that you mentioned…

“an o’ring between the matting surface of the motor and prop guard”

The o ring is on the motor

I found a picture of the o-ring.

Is it normal for oil to leak out a little bit? My FR motor had a small amount of oil leak out around the seal after setting up my VESC before it was ever used. After each use there is always a small about of oil residue. Does this mean water is getting into my motor?

Also, is the large screw in the housing a fill hole? Should I dump the oil out to see if water is in it?

Check with David but I don’t think it should leak mate. I know for a fact they are pressure tested at 9psi at the Lift factory.

Are you using it with the cone or prop guard? Super important to always use this motor with either of them as there is an additional lip seal in there plus this is what hold the primary lip seal in place.

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Yes, I used the guard at first then switched to the cone. When I removed the guard to install the cone it was obvious the first seal was leaking because there was oil within the circumference of the O-ring. The second seal also leaks a little on both the cone and the guard. Perhaps the first seal is leaking more than normal such that the second seal can’t contain it.

It’s a pressure release screw. When the units are assembled there needs to be a vent to let out the air trapped inside otherwise the rear seal will try push back out. Once the rear section is on the small screw is sealed in to waterproof the unit.

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David said a small amount of mineral oil leaking out is normal and it should be refilled once per year through that small screw.

It is. Actually the oil is in the pod partially for this reason.

Oil comes out because the inside of the motor gets hot while the outside stays cool (assuming the motor is running in water). As the oil and inside components are getting warm, they tend to push against the lipseal and eject some oil outside.
The dangerous part though, is when the motor internals are cold but the outside warm (exemple when you let the foil on the beach under the sun). In this last case, water will tend to be “sucked” inside the motor when put in the water.

Interestingly no one bothers to explain this to customers even if this really important, because nor David, nor Lift are making those motors. They barely know the specs so I wouldn’t expect much, but yeah, those motors need servicing…

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Good to know. My current motor was restored after drinking a bit too much salt water… They do need servicing indeed.
Always though it could be a good idea to have the mineral oil to be titnted with a die so a leak would be easier to spot.
Things I pay attention at:
-The single lip seal are really soft to not mark the shaft but they start open up after a while. It is quite noticeable when you compare an old one with a new.
-There is only one oring on the cap. When you open the cap it get cut by the countersunk screw hole. I never reuse this oring when I open the cap. Always use a new one.
-There is a retaining snap ring on the end of the shaft that act as a stopper to prevent play. If you start to get more than 2mm of axial play in the shaft do not use your motor, it means the snap ring is off the groove and it can mess up the internal wires. You get this snap ring from Smalley.

Otherwise amazing motor.

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I had to open my FR motor to check for axial play, so I’ve done some ghetto engineering and build a quick puller:

The rear snap ring on one of my shafts got loose so I realized the cause for the axial play of the rotor.

So I was wondering where to find this ring from Smalley. Would you happen to have a link @Manufoil?
I ended up fitting a stainless pipe to keep the distance:

It also works fine for 100+ rides. :call_me_hand:

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I contacted Smalley directly and they were cool enough to send a few. Honestly I think your solution is way better and will probably do this next time if I have too :sweat_smile:
I’m wondering if they use these kind off snap ring so they pop off on purpose if there is an excessive axial load.

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Took mine apart , cleaned and smooth all the machine work around screws holes , O-ring groove ( extreme tight play ) , really hard to put correctly in place , but that solved my leaking issue

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