[Learjet]

Originally Posted by 9-d-9

How did you confirm the vacuum? I agree the damage to the seal may have already been present. I've noticed all three of my leaks the next morning after the first drive. The occurances have also occured the next day after extended +1 hour of freeway speed driving... so it's very likely a vacuum is building during cool down.

I unscrewed the axle vent and could hear a significant rush of air into the axle and could feel the vacuum as I unscrewed the vent. The vent is a one-way check valve it lets air out, not in.