How do I remove and refit the saildrive seal on an Arcona 340?

Replacing the main saildrive diaphragm on an Arcona 340 means hauling out, supporting the engine, separating it from the saildrive and dismantling the drive far enough to fit the new rubber diaphragm. First identify the saildrive model and check which seal needs replacing: the watertight diaphragm or the thin rubber fairing flap glued beneath the hull, as each requires different work.

Identify the seal and kit

Read the identification plate on the saildrive and record its model, product number and serial number. The engine badge alone cannot identify the drive, particularly if either unit has been replaced. Volvo Penta 120S and 130S installations use different parts and procedures.

The large diaphragm clamped inside the hull keeps seawater out. The external rubber flap smooths water flow around the leg; it does not form a watertight seal. Replacing the flap does not renew the diaphragm.

The usual replacement interval for Volvo Penta saildrive diaphragms is seven years. Confirm the requirement in the manual for the fitted drive. If the installation date is unknown, schedule replacement even if the visible rubber looks sound.

• Order the diaphragm kit against the drive serial number, including the specified joint seals and replacement fasteners.
• Obtain the workshop procedure and torque figures for that exact model before dismantling.
• Have a torque wrench, lifting tackle, engine support, drain tray and clean bench ready.

Prepare and remove the drive

Have the yard secure the boat ashore. Isolate the starting battery and support the engine and saildrive independently before releasing any mounting or coupling bolts.

On the Arcona 340, first inspect access through the companionway and aft engine panels. Measure the space available to slide the engine forward and lift the drive clear. Joinery and equipment arrangements vary between boats.

1. Photograph the installation, label connections and record engine-mount positions. Drain the saildrive oil into a clean container and inspect it for water or metallic debris.
2. Remove the propeller and any components that prevent the leg passing through the hull opening. Record the order of spacers, washers and anodes.
3. Disconnect the gear cable, cooling-water connection and any electrical connections that obstruct removal. Release hoses or wiring that would stretch when the engine moves.
4. Support the engine, separate its connection to the saildrive and move it forward far enough to provide clearance. Do not leave its weight hanging from the remaining mounts.
5. Support the drive, remove its mounting and diaphragm-retaining components in the workshop-manual sequence, and lift the assembly clear through the hull opening.

Do not lever against the hull moulding or use coupling bolts to force reluctant components apart.