I've just bought a second-hand prop jet (D/C F-20) to work up for my waiver, but one of the Main leg SpringAir retracts doesn't want to extend fully. It gets about 3/4 extended under the spring pressure, but needs a little assistance to fully lock down. This happens even without the air line attached and just manually closed and released. The gear is only a Robart wheel on a wire leg,so weight isn't the issue. I've tried oiling the pivot but to no effect.

Thanks in advance.

Paul