Things to Know About Hydraulic Steering

Things to Know About Hydraulic Steering
Hydraulic steering has many advantages over cable steering but not totally without problems. Let's say you notice oil dripping from the steering helm, or maybe the steering cylinder. The consequences of low fluid levels can be serious–like loss of steering while underway!

When a leak causes the fluid level to fall below the safe-operating minimum, the hydraulic pump can force air into the system. Common symptoms include need for greater steering effort, or maybe the boat will not steer when you turn the wheel. Sometimes you feel a slight thumping when you turn the wheel. This is the pump cavitating–picking up air instead of fluid.

Hydraulic steering has four major components; the helm (includes pump and fluid reservoir on most systems), hoses to transport fluid to the steering cylinder, the cylinder itself, and of course the fluid. Leaks can develop in all of them. The basis of any hydraulic system is that a fluid cannot be compressed. However, air can be. Air in the system can be a real problem.

So... you have air in the system–how do you refill the reservoir and bleed the air out? SeaStar and UFlex are the most popular systems and the fill port is located at the top of the helm. I recommend the following procedure because it fills the reservoir and bleeds air in a single operation.

Quart bottles of fluid have a filling tube with a screw fitting at the end, smaller tube-type containers have threads on the nozzle. In either case, remove the filler cap and screw the nozzle into the threads. With quart-size bottles, invert and hold the bottle above the reservoir and allow the tube to fill by gravity. Smaller containers are screwed-in, container upside-down. Begin turning the steering wheel slowly, full right to full left, several times until the steering becomes synchronous to wheel movement–you will see bubbles rising in the tube on larger bottle.

Remove the filler nozzle and dip the edge of a clean towel into the port to pull out excess fluid–until all the threads are visible. Replace filler cap. Wrapping a towel around the helm and placing another on the deck below it catches drips. Zip the applicator with container of fluid and towel in a gallon plastic bag and store on the boat for future use. Fix the leak when time allows but always be prepared to add fluid as needed until repairs are made.

Chris Mapp

Coastal Bend Marine
Port O'Connor TX