LX465 Boom Not Lifting Under Load

[LX465NH]

The boom on my LX465 will not raise with an attachment on but works when bare at full throttle. The tilt and drive functions work fine, only the boom lift is affected. Any thoughts on what the problem could be?

 

[brdgbldr]

The boom on my LX465 will not raise with an attachment on but works when bare at full throttle. The tilt and drive functions work fine, only the boom lift is affected. Any thoughts on what the problem could be?

Could be a bad piston seal in one of the lift cylinders.