Bleeding Steering Systems: Twin Engines, Simple Steps

Bleeding a boat's hydraulic steering system is critical for the vessel to handle as expected. This process requires two people: one at the steering cylinder and the other at the helm. The person at the steering cylinder will open and close the bleeder valves and push the engine to get rid of any additional air, while the person at the helm will fill the reservoir with hydraulic steering fluid. This procedure is the same for twin-engine boats, but it must be done on each cylinder one at a time.

Bleeding a single cylinder hydraulic steering system

Bleeding a single-cylinder hydraulic steering system is a relatively straightforward process, but it does require two people: one at the helm and another at the steering cylinder. Here's a step-by-step guide on how to do it:

Step 1: Prepare for the Bleeding Process

Get some oil-absorbent pads ready to catch any hydraulic fluid that may leak out during the process. This will help minimise the mess. It is also recommended to have the necessary tools on hand, such as tubing and clean, empty bottles.

Step 2: Position the People Involved

Position one person at the helm and another at the steering cylinder. The person at the helm will be in charge of filling the reservoir with hydraulic steering fluid, while the person at the steering cylinder will be opening and closing the bleeder valves.

Step 3: Fill the Reservoir with Hydraulic Steering Fluid

Open the reservoir at the helm and top it off. Then, connect the filler tube to the oil bottle and invert the bottle so that the filler tube fills with hydraulic steering fluid. Poke a hole in the bottom of the inverted bottle to allow the fluid to flow freely into the system. Ensure that the person at the helm keeps an eye on the filler tube and replaces the bottle if it runs empty to prevent introducing more air into the system.

Step 4: Turn the Wheel and Open the Bleeder Valves

Turn the wheel all the way to starboard. The person at the cylinder should then open the starboard-side bleeder valve and prepare a container to catch any fluid that comes out. Attaching a short length of hose to the bleeder valve can help direct the fluid into the container and minimise the mess.

Step 5: Turn the Wheel to Port and Close the Valve

The person at the cylinder needs to hold the cylinder in place while the person at the helm turns the wheel to port. Keep turning until air bubbles stop coming out of the bleeder valve. Once there are no more air bubbles, the valve can be closed.

Step 6: Repeat the Process for the Portside Bleeder Valve

Repeat the same process for the portside bleeder valve. Turn the wheel to starboard, open the portside bleeder valve, and catch any fluid that comes out. Then, turn the wheel to port until air bubbles cease, and close the valve.

Step 7: Check for Smooth Steering

To ensure that the system is fully purged of air, try turning the wheel from lock to lock. If the steering is smooth and there are no bumps or hesitations, the bleeding process has been successful.

Remember, it is important to check for any leaks or connection issues before bleeding the system, as air in the hydraulic steering system is usually due to a leak at a connection point.

The process of bleeding a twin cylinder hydraulic steering system

The Process of Bleeding a Twin-Cylinder Hydraulic Steering System

Bleeding a twin-cylinder hydraulic steering system on a boat is a critical procedure to ensure optimal performance and handling. This process is usually done by two people and involves the following steps:

Step 1: Prepare the Necessary Tools and Materials

Before beginning the bleeding process, ensure you have the following: oil-absorbent pads, hydraulic steering fluid, a filler tube, an oil bottle, and a container to catch any fluid. It is also recommended to have a short length of hose attached to the bleeder valve to minimize mess.

Step 2: Position the Two Individuals

One person should be stationed at the steering cylinder, while the other takes their place at the helm. The person at the cylinder will be responsible for opening and closing the bleeder valves and pushing the engine to remove additional air. Meanwhile, the individual at the helm will connect the filler tube and oil bottle, fill the reservoir, and turn the wheel.

Step 3: Fill the Reservoir and Turn the Wheel

At the helm, connect the filler tube to the oil bottle and open the port on the helm. Puncture the plastic side of the bottle to allow air pressure to equalize, enabling fluid to flow into the reservoir. Continuously turn the wheel to force fluid through the system, including the reservoir, pump, and hoses, back to the steering cylinder.

Step 4: Open the Starboard Bleeder Valve

Once the helm is filled with hydraulic steering fluid, the assistant should turn the wheel hard to the right. Once the steering cylinder has moved all the way over, crack open the starboard bleeder valve and allow about a half quart of fluid to flow through. Keep constant pressure on the helm by continuously turning the wheel to the right.

Step 5: Close the Starboard Bleeder Valve and Repeat on the Portside

After releasing a sufficient amount of fluid, close the starboard bleeder valve. Now, turn the wheel to the left and repeat the process on the port side. Open the portside bleeder valve and allow fluid to flow out while the assistant maintains constant pressure on the helm by turning the wheel to the left.

Step 6: Alternate Between Sides and Check for Air Bubbles

Alternate between the starboard and port sides several times until all air is purged from the system. You can check if the system is fully purged by turning the wheel from hard over to hard over. If the flow is smooth, with no bumps or hesitations, the bleeding process is complete.

It is important to remember that air in a boat's hydraulic steering system usually indicates a leak at a connection point. Therefore, it is recommended to inspect all hydraulic fittings closely and fix any leaks before adding hydraulic fluid to prevent the issue from reoccurring.

The importance of a properly bled hydraulic steering system

A properly bled hydraulic steering system is critical for a boat to handle as expected. If your boat has two stations, you will need to bleed each one individually. The process is not difficult, but it does require two people: one at the helm and the other at the steering cylinder.

Firstly, get some oil-absorbent pads ready in case any hydraulic fluid spills (which is usually the case). Open the reservoir at the helm and top it off. Then, connect the filler tube and oil bottle, and invert the oil bottle so the filler tube fills with hydraulic steering fluid. Poke a hole in the bottom of the inverted bottle so the fluid can freely run out of the bottle and into the system. The person at the helm needs to keep an eye on the filler tube and replace the bottle if it runs empty, to prevent introducing more air into the system.

Next, turn the wheel all the way to starboard. Then the person positioned at the cylinder should open the starboard-side bleeder valve and prepare a container to catch the fluid that comes out. It’s a good idea to attach a short length of hose to the bleeder valve so you can direct any fluid that comes out into a container to minimize the mess. The person at the cylinder needs to hold it in place while the person at the helm turns the wheel to port, until air bubbles cease coming out of the bleeder valve. When no more air is coming through, the valve can be closed. Now, repeat the process with the portside bleeder valve.

To check if the system is fully purged, you should be able to turn the wheel smoothly from lock to lock without bumps or hesitations. A sea trial is the best way to get a feel for how smoothly the steering system is working, but at the dock, you can usually feel if there are any major air bubbles remaining.

Using a Seastar Hydraulic Steering Bleed Kit

Bleeding or purging a SeaStar hydraulic steering system is a straightforward process but it does require two people. This guide is for bleeding/purging a SeaStar single helm, front mount cylinder system or single helm, side mount/splashwell mount system.

Step 1 – Preparation:

To purge the hydraulic steering, you will be putting hydraulic fluid into one end of the system and draining it out of the other. You will need something to add the fluid into the helm pump and something to catch the fluid being expelled from the steering cylinder.

Step 2 – Fill the Helm Pump:

Fill the helm pump with hydraulic fluid before connecting the filler tube. It is much easier to fill the helm this way and it reduces the possibility of air becoming trapped in the helm pump. Once the helm pump is full, connect the gravity feed system to the helm via the filler tube. If you are not using a gravity feed system, connect a new bottle of hydraulic fluid to the helm pump with a filler tube.

Step 3 – Extend One Side of the Cylinder Steering Rod:

With the helm pump full and the gravity feed system topped off, turn the steering wheel in one direction until the steering cylinder rod has fully extended. Turning clockwise with a front mount cylinder system will cause the rod to extend starboard, and vice-versa. Turning anti-clockwise with a side mount/splashwell mount cylinder system will cause the rod to move in a port direction, and vice-versa.

Step 4 – Bleed the First Side of the Steering System:

Have your assistant hold the cylinder rod to prevent it from sliding back into the cylinder. Do not use grips or pliers to hold the cylinder rod as those may damage it. Only hold the rod by hand. While your helper holds the rod, steadily turn the steering wheel in the opposite direction to which you originally turned it. This will begin to draw new hydraulic fluid from the gravity feed into the helm pump. As the new fluid enters this side of the system, the old fluid and any air will bleed out of the open bleeder and into the container.

Step 5 – Extend the Other Side of the Cylinder Steering Rod:

Keep turning the wheel until the steering cylinder rod on the other side becomes fully extended. Turning anti-clockwise with a front mount cylinder system will cause the rod to extend port, and vice-versa. Turning clockwise with a side mount/splashwell mount cylinder system will cause the rod to move in a starboard direction, and vice-versa.

Step 6 – Bleed the Second Side of the Steering System:

Repeat Step 4 by having the helper hold the cylinder rod to prevent it from moving, while you turn the steering wheel in the opposite direction from which you just turned it. This time, you are drawing new hydraulic fluid through this side of the hydraulic system and purging the old fluid out of the open bleeder into the container.

Step 7 – Check the Steering System:

Turn the steering wheel to full lock in one direction, and then apply additional force to pressurize the system. Keep pressure on the wheel while your assistant checks all the hydraulic connections and fittings for leaks. Correct any leaks that are found. Next, turn to the lock in the opposite direction and repeat the process.

Pro Tips:

• Cut off the bottom of an old SeaStar hydraulic fluid bottle, then turn the bottle upside down and suspend it above the helm pump. Connect the bottle and helm with a filler tube to establish a gravity feed system.
• Use a SeaStar filler kit as the filler tube. The kit screws snugly into the bottle at one end and the helm at the other, which means there are no leaks, drips, or mess to clean up.
• Watch the fluid level in the helm pump as you apply pressure at hard lock. A drop in fluid level indicates there is still air in the system and it must be bled again.
• SeaStar recommends that all helm pumps are filled to the bottom of the filler hole, and that the fluid in horizontally mounted helms never falls lower than 1/4" from the filler hole, and fluid in helms mounted at 20° (or with a vertical wheel shaft) never falls lower than 1/2" of the filler hole.

Step-by-step guide to bleeding a boat hydraulic steering system

Bleeding your boat's hydraulic steering system is critical for maintaining smooth handling and responsive steering control. This process typically requires two people and can be done by following these steps:

Step 1: Preparation

Firstly, gather the necessary tools and materials, including oil-absorbent pads, hydraulic steering fluid, and a container to catch expelled fluid. You will also need a filler tube and a hydraulic steering fluid bottle.

Step 2: Filling the Reservoir

Open the reservoir at the helm and top it off with hydraulic steering fluid. Then, connect the filler tube to the oil bottle and the helm. Invert the oil bottle so that the filler tube fills with hydraulic fluid. Poke a hole in the bottom of the inverted bottle to allow fluid to flow freely into the system.

Step 3: Bleeding the System

With one person at the helm and the other at the steering cylinder, turn the wheel all the way to starboard. The person at the cylinder should then open the starboard-side bleeder valve and prepare a container to catch the fluid that comes out. It is recommended to attach a short hose to the bleeder valve to minimize mess.

Step 4: Turning the Wheel

The person at the cylinder should hold the cylinder in place while the person at the helm turns the wheel to port. Continue turning the wheel until air bubbles stop coming out of the bleeder valve. Close the valve when no more air is coming through, and repeat the process on the port side.

Step 5: Checking the System

To ensure the system is fully purged, turn the wheel smoothly from lock to lock. There should be no bumps or hesitations. A sea trial is the best way to test the steering, but you can also feel for any remaining air bubbles while docked.

Additionally, before bleeding the system, it is important to check for any leaks. Air in the system usually indicates a leak at a connection point, so inspect all hydraulic fittings closely and fix any leaks before adding hydraulic fluid.

Frequently asked questions