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  • Potential Steering Loss – Teleflex Sea-Star Hydraulic Steering Systems

    One of the systems on our boats that we nearly always take for granted is the steering. The reason is simple: it always works, it never causes problems and it requires no maintenance. But what do you do if you lose your steering?

    Steering loss can happen and I would be willing to bet that very few of us have the necessary ingredients on our boats or are prepared for an emergency fix.

    Any boat with Teleflex Sea-Star hydraulic steering is subject to losing it’s steering. For Sea Ray boats this usually means inboard and v-drive powered boats above 32 feet. Unfortunately, when the Sea Star system fails, it is seldom a partial or intermittent failure.

    How The System Works:

    The basic Sea Star system is a hydraulic pump operated by the rotation of the steering wheel. Hydraulic oil is pumped out of one port on the pump and into the hydraulic line that runs to the stern of the boat where it then connects to one port on the steering cylinder. This causes the piston and attached cylinder rod or actuator to move toward the opposite end of the cylinder. The ball joint on the end of the cylinder rod is attached to the boat’s rudder linkage so moving the cylinder causes a similar action in the rudders. As the piston moves, oil is displaced from the opposite end of the cylinder via the port on the other end. The displaced oil travels back to the pump and enters the opposite port. The hydraulic steering system is a closed system. The oil in the lines, the cylinder and the pump form the reservoir for the pump. The cylinder has internal check valves so the rudder cannot move and remains stationary unless the helm pump is turned and oil flows into the cylinder.

    Steering Loss:

    Any time the oil level in the Sea Star system gets low enough, the helm pump will ingest air. Since air is compressible, once the level is low, the helm pump just compresses the air it has ingested when the steering wheel is turned. The air compresses in the lines instead of the pump moving hydraulic oil which means you lose your steering. The helm pump’s reservoir is small so it doesn’t take much of a leak to allow air into the system. The symptoms you will most likely notice are “spongy” or soft steering and a lot of play between port and starboard reaction to steering input. The steering play gradually increases until you have a revolution or so of play followed by a soft feel in both directions and no rudder deflection when you turn the wheel. Long before this, however, the boat becomes unsafe since its steering reaction is so vague and sloppy that you lose steering control.

    For air to get into the system, hydraulic oil must get out. So, where does the oil go?

    The first place to check for leaks is all of the fittings connecting the hydraulic hoses to the pump, to the cylinder, and if equipped, to the power assist module and the autopilot pump. It is also possible that the hydraulic lines, which are usually plastic, may have gotten crimped or physically damaged with clamps or screws securing them or something else somewhere between the helm pump and the transom area.

    The other main source for steering system leaks is the steering cylinder.

    Below is a stock photo of a steering cylinder from Teleflex:



    Note that the piston and mounting bracket are in the center of the cylinder and that the cylinder rod extends on both ends. Depending upon where you leave your steering wheel, a portion if the cylinder rod is always exposed while its opposite end is protected inside the cylinder packing gland and seal. The exposed cylinder rod can eventually become pitted due to its exposure to moisture and a corrosive atmosphere. Pitting on the cylinder rod will eventually wear or cut the seal in the end of the cylinder……..and you get a leak.

    Other than wiping down the exposed cylinder rod with some hydraulic oil (nothing else-solvent based spray lubricants will dry out the seals!), there isn’t much you can do to prevent the pitting. Fortunately, it takes a long time for the steering cylinder to become damaged to the point of leaking hydraulic oil. Of course, how wet your bilge is, whether your deck drains drip into the bilge, and how salty the water you are in has a big effect on how fast the cylinder rod will get pitted. Once the cylinder rod is pitted, replacing the packing or seals in the end of the cylinder is a waste of time since the pitted area will just cut the new seals. A new steering cylinder is the quicker and better remedy that requires a fraction of the labor that re-sealing the cylinder does.

    How Do We Get the Boat Home?…….An Emergency fix

    When you feel the steering start to get spongy, you are already out of hydraulic oil and are ingesting air into the system which also means you don’t have much time before you lose steering. On boats with an autopilot, you can steer using the “jog” buttons on the AP since most autopilot pumps have some oil capacity. Without an autopilot, you just have to slow down and steer with the throttles or by shifting your transmissions into and out of gear. With a single engine boat, when the steering pump ingests air, you are done …..call the towing company who gave you the sticker you put on your dash.

    All of us with Sea-Star hydraulic steering should have a quart of Sea Star hydraulic oil in our spares kit. I know it is expensive, but a quart of hydraulic oil and a very small funnel will go a long way and can quickly restore your steering if they are on the boat and not in your dock box. Just top off the helm pump with oil and turn the wheel from port to stbd several times to purge the air and you will have your steering back.

    Tip: A cheap plastic wine glass with a hollow plastic stem and the base cut off makes a great and inexpensive funnel to refill either the helm pump or your trim pump.

    Copyright 2010 Frank A. Webster
    Comments 2 Comments
    1. Searaybio270's Avatar
      Searaybio270 -
      Frank,
      First thank you for taking the time on this steering issue back in 2010. I posted this morning around 1:30am (couldn't sleep) about my steering being sluggish. This posting you did really helped. At least now I know that there really is an issue and not that I think there is an issue.
      There is a looming question I have: Where do i go, MM/Sea Ray/others so I can find this steering mechanism? I don't have a manual that show the engines, steering, trans info etc.
      Thanks again,
      Joe
    1. thomas lee's Avatar
      thomas lee -
      I have a 1984 seray sedan bridge 340 my first boat,any way the issue I have is related to sytten steering I am trying find the routing of the plastic lines one seems to be leaking but cannot seem to find. is there a routing diagram along with all componets listed up and down steering stations. also a bleeding proceedure. tom