How to Repack Stuffing Box

Step-by-Step Repacking Packing

Step 1. Preparation

Before beginning the repacking process, ensure your boat is hauled out or the shaft is not turning. Safely access the stuffing box and use two wrenches to loosen the lock nut and packing nut. This will allow you to remove the old packing material and install new packing rings.

Step 2. Remove old packing

Using a pick tool or packing removal tool, carefully extract all the old packing material from the stuffing box. Be thorough, as leaving any old packing behind can compromise the seal.

Once removed, inspect the shaft for any damage, such as scoring or corrosion. Clean the shaft and stuffing box thoroughly before installing new packing. Determine the correct size for the new packing by measuring the shaft diameter and stuffing box depth.

Step 3. Install new packing

Measure and cut the new packing rings to the appropriate length, ensuring a snug fit around the shaft. Install the rings one at a time, staggering the joints by 120 degrees to prevent a continuous leak path.

Typically, 3-4 rings of packing are sufficient. Avoid overpacking, as this can cause excessive heat and wear on the shaft. Use a packing nut or follower to compress each ring as you install it.

Step 4. Reassemble and adjust stuffing box

After installing the new packing, replace the packing nut and tighten it until you feel light resistance. Do not overtighten, as this can cause overheating and damage to the shaft. Secure the packing nut with the locking nut using two wrenches.

Once reassembled, adjust the packing nut to allow only 2-3 drips per minute when the shaft is turning. Monitor the temperature of the stuffing box and shaft, and make further adjustments if overheating occurs.

When to Repack Your Stuffing Box

• Excessive leaking: If you notice more than the recommended 2-3 drips per minute when the shaft is turning, it’s time to repack.
• Frequent adjustments: If you find yourself constantly adjusting the packing nut to control leaks, the packing material may be worn out.
• Overheating: If the stuffing box or shaft is overheating, it could be a sign that the packing is too tight or needs replacement.

The recommended repacking intervals vary depending on the type of boat:

• Power boats: Repack every 1-2 years or 100-200 engine hours
• Sailboats: Repack every 2-3 years or 500-1000 nautical miles

FAQs

Can you repack a stuffing box in the water?

While it is possible to repack a stuffing box in the water, it is not recommended. Water can interfere with the proper installation of the packing material and make it difficult to achieve a proper seal. It’s best to perform the repacking process with the boat hauled out or the shaft securely supported and not turning.