I fixed one by jacking the car up at an angle so I could pull the tube w/o dumping fluid, dry/degrease the area REALLY well with brake cleaner and lacquer thinner then reinstall the tube with a new o-ring AND a smear of RTV at the mating area and o-ring. Reinstall, complete with the securing bolt (to prevent further movement of the tube, and let cure for 24 hours before leveling car.
It worked.

Also--they sell many different o-rings--use the thickest one you can, and the RTV helps here to, acting as a lube.