Here is a homemade "steering luber" which has worked well in freeing up sticking steering cables. Also, use it as regular maintenance to prevent cables from sticking in the future which they are prone to do over time. Following is the list of steps for its use. Note: In the lower left corner of the picture, the label should read "Pivot Tube".
(1) Unhook the cables from the motor.
(2) Hook the cable to the luber (put teflon tape on threads each time, stops any possible leaks).
(3) Hang or hold luber at approx. 30 degrees, so contents of luber will cover cable.
(4) Remove cap (or plug) from "T", and fill with penetrating oil (I use Kroil).
(5) Place some rags under helm to keep oil off your carpet.
(6) Plug air hose to luber (I use 140#) and turn wheel back and forth until oil drips out of cable at helm.
(7) Remove air, dump remaining oil from luber.
(8) Fill luber with mixture (I use liquid wrench, 1/2 pint, Neversieze (about a cup), brake fluid, 1/2 cup, ATF, about a cup, should mix a little over a pint).
(9) Reapply air, turn wheel until mixture drips from helm (takes a little longer than penetrating oil, because it's thicker) .
You're about 1/2 way there. Do the same for both cables. NOTE: be sure to clean out the tubes on the motor before reinstalling the cables to the motor (a special inexpensive automotive valve guide cleaning wire brush tool attached to your portable drill along with lacquer thinner works well for this operation - purchase at an automotive supply house). Install Neversieze to cables before inserting into the tubes. Try to find hi temp (silver or grey) Neversieze. I can't say how long this will keep things greased up, but I think if you do this every year you may never have to buy new cables. You never know!
If you have any questions, e-mail T-Rex at firstname.lastname@example.org