TL;DR
Shaft seal leaks are the most common oil leak path on the Movigear. Confirm which seal is leaking, drain the oil, and replace the seal. Check that the shaft surface is not scored before fitting the new seal.
What you might see
- oil dripping or pooling under the gearbox
- oil staining visible around output shaft
- oil level dropping between scheduled services
- contamination of conveyor belt or product from oil drips
Likely causes
Worn radial shaft seal (lip seal) at the output shaft from age or contamination
Degraded housing gasket or O-ring at the oil fill, drain, or inspection cover
Scored shaft surface under the seal from external contamination or misalignment
Excessive internal pressure from a blocked breather preventing pressure equalization
Required tools
- LOTO kit
- Seal puller or seal removal screwdriver
- Seal driver sized to seal OD
- SEW-approved replacement seal and breather
- Correct gear oil for refill
- Drain container
Safety first
- Hot gear oil causes burns. Allow the unit to cool before draining.
- Confirm the shaft surface condition before fitting the new seal to avoid an immediate re-leak.
Procedure
- 1
Identify the leak source. Clean the housing and surrounding area and run the unit for 30 minutes. The first re-wetted area locates the leak.
- 2
Lock out the motor and allow the oil to cool.
- 3
Check the vent or breather plug first. A blocked breather pressurizes the housing and forces oil past seals. Clean or replace the breather before replacing the seal.[1]
- 4
Drain the gear oil into a clean container.
- 5
Remove the output shaft seal using a seal puller or screwdriver inserted behind the seal lip. Do not score the bore or shaft.[1]
- 6
Inspect the shaft surface under the seal for scoring or corrosion. A polished band from the old seal is normal. Any groove deeper than 0.1 mm will cause a re-leak.
- 7
Apply a small amount of SEW-approved assembly grease to the new seal lip and press it squarely into the bore with a seal driver sized to the seal OD.
- 8
Refill with the correct oil grade and quantity per the SEW Movigear nameplate. Replace the drain plug with a new sealing washer.
- 9
Run the unit for 15 minutes and inspect for leaks at the new seal before returning to service.
Sources
SEW-Eurodrive Movigear Operating Instructions, SEW-Eurodrive
SEW-Eurodrive Movigear Installation and Operating Instructions, shaft seal replacement procedure (general)
View source
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