Most of us are convinced the rubber tube needs lots of grease, applied through grease nipples (Zerk fittings) both at the base of the tube and the upper bearing. Get a grease gun and pump in until it won't take any more.
For wobble, also eliminate the common issue of the top bearing, visible at the helm cockpit floor, getting invisibly loose. For that, check the nuts that hold it, located under the cockpit. Requires a flashlight, a wrench and a chiropractor.