Filling and Purging a SeaStar Hydraulic Steering System

So you need to fill and purge your hydraulic steering system and don’t have access to SeaStar’s Power Purge Jr. (We did an article about this earlier – check it out here!) – what do you do? The old-fashioned way, of course!

To manually fill and purge your system, you will need two people to assist. This is so that one person can be at the cylinder and the other at the helm. One person may not be able to remove all the air from the system. This would resulting in spongy, unresponsive steering. The whole process should take about 30 minutes.

Before you start it’s important to identify your setup. Is it single helm/single cylinder? Or maybe it’s a twin helm/single cylinder or single helm/twin cylinder or even twin helm/twin cylinder. Identifying the system will help you ensure you have enough SeaStar* hydraulic steering fluid for the job. We recommend 2 bottles for single station/single cylinder systems plus 1 additional bottle for each additional helm, cylinder, or auto pilot.

Note that during the entire filling procedure, oil must be visible in the filler tube. DO NOT allow the oil level to disappear into the helm pump as this may introduce air into the system and increase your filling time.

For the purposes of this article the following five step process will focus on a single helm, single cylinder system, and we have assumed that the cylinder is already attached to the engine and the system has already been drained or has never been filled.

 

Step 1

  • Remove the vent plug from the top of the helm. Screw the threaded end of the filler tube into the helm filler port.
  • Remove the cap from the steering fluid (oil) bottle and, holding upright, screw into the filler tube bottle cap. Turn the oil bottle upside down and poke a hole in the bottom of the bottle. This will allow the oil to flow out of the bottle and prevent an airlock.
  • Fill the helm pump full of hydraulic oil so that it is visible in the filler tube. (Filling the helm full of oil can be done faster if oil is poured into the helm prior to connecting filler tube and oil bottle to the helm.)
  • Oil should always be visible in the filler tube. Use the next bottle of fluid at any time during the procedure in order to maintain the oil level. DO NOT proceed with step two until the helm is full.

Step 2

  • Turn the steering wheel clockwise (starboard) until the cylinder rod is fully extended on the right side of the cylinder (the front of the engine will be over to the left). If there is no oil in the system you may have to push gently on the engine.
  • Open the right side (starboard) bleeder valve on the cylinder.
  • Holding the engine over to the left and with a suitable container under the bleeder valve, turn the steering wheel counter-clockwise (port) until 10-20 seconds of air-free fluid has escaped from the bleeder then close the bleeder.
  • While continuing to turn the wheel close the right-side (starboard) bleeder.
  • NOTE: Ensure you turn the steering wheel slow enough that the engine does not move.

Step 3

  • Continue turning the steering wheel counter-clockwise (port) until the cylinder rod is fully extended to the left. (Steering wheel will come to a stop).
  • Open the left (port) bleeder valve.
  • Holding the engine over to the right (starboard) and with a suitable container under the left (port) hand bleeder valve, turn the steering wheel clockwise (starboard) until 10-20 seconds of air-free fluid has escaped from the bleeder then close the bleeder.
  • While continuing to turn the wheel close the left side bleeder
  • Remove the oil bottle from the helm and ensure the level of the oil is correct in the helm.
  • NOTE: Ensure you turn the steering wheel slow enough that the engine does not move.

Step 4

  • Turn your steering wheel to hit hard over in both directions and force (each direction) the wheel one full turn past.
  • NOTE: Doing this will be physically difficult and it may feel like the system will break. Rest assured, the system is designed for this.

 

NOTE: Helms mounted with the wheel shaft completely horizontal MUST be filled to the bottom of the filler hole AT ALL TIMES. DO NOT allow oil level to drop more than 1/4” below filler threads.

NOTE: Helms mounted on a 20 degree angle, or, with wheel shaft in the vertical position, the oil level should be within 1/2” from the bottom of the filler hole.

When the steering system has been properly bled, steering wheel turns from hard over to hard over will be as shown in helm manual e.g. a 1.7 cubic inch helm will have 5 turns lock-to-lock. Most Baystar kits will have 5.2 turns lock-to-lock and most pro kits will have 4.2 lock-to-lock. Smaller helms will have more turns, larger helms will have fewer. If the helm feels spongy, unresponsive, or has more than the required turns you will need to repeat the steps above.

As a final check, ensure unrestricted movement of the steering system and hoses at all trim/tilt positions. Confirm that the engine(s) are turning in the right direction and make sure there are no leaks from connections, fittings, seals and hoses.

* SeaStar Solutions recommends use of SeaStar Steering Fluid ONLY in our hydraulic steering systems. SeaStar Steering Systems have been engineered and validated using our proprietary SeaStar Hydraulic Steering Fluid which is engineered with a special additive package that contains anti-foaming and anti-rusting agents, anti-oxidants, viscosity stabilizers, corrosion inhibitors, wear additives as well as water emulsification additives.

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