Welcome back to “How to…”. In this series, we guide you on extending the lifespan of EWFMs products. Previously, we covered maintenance for Model 2175, 2174 Swivel Joints, Manntek Dry Disconnect Couplings, and installing the Model 2874 LPG Bottom Loading Arm. This edition focuses on servicing your 4″ safety breakaway coupling, a standard component in our bottom loading arms.
Inspect couplings daily for dirt, seal, or physical damage. Service intervals depend on local rules and application conditions. For new applications with unknown parameters, initial service after one year is recommended. Adjust further intervals based on inspection results, starting with seal replacement, and then replacing worn or damaged components.
Before you start:
- Before starting maintenance, depressurize the system and clean the parts. Wear protective goggles and avoid handling O-ring seals that look charred, gummy, or sticky.
- Use tweezers and wear neoprene or PVC gloves. Avoid touching adjacent parts with bare hands. Rinse the parts again before beginning the “daily inspection.”
Disassembly Process:
After the coupling has released and servicing is required, there is a danger that fluid could still spurt out, which is why special protective equipment is needed. Here are the steps for maintenance:
Step 1: Screw out the damaged parts of the breaking bolts and check for any wear and tear.
Step 2: Remove the flat seal (if available) and unscrew the three screws that lock the spindle steering. Press down the spindle steering and turn it free, releasing it carefully as it is spring-loaded.
Step 3: Take out the spindle steering, spring, body, piston, spring cap, and PTFE-bushing from the coupling body.
Step 4: For the Piston O-Ring, replace the O-ring (pos.3) on the piston with a new greased O-ring, ensuring equal pressure around the O-ring. Press the O-ring into the groove on the piston using grease suitable for O-ring material.
Step 5: For the Inner Body O-Ring, remove the nine screws and detach the coupling flange from the body. Replace the O-ring (pos.19) on the body with a new greased O-ring. Use only grease suitable for the O-ring material. Reattach the coupling flange to the body using Loctite® 243 on the nine screws. The recommended tool for this is the Allen key 4 mm.
Step 6: For the Mounting Piston, introduce the piston into the valve seat as shown, ensuring it’s in a relaxing position. Take care as the piston may stick out on the other side due to its larger diameter than the three brackets for the piston guide.
Reassembly Process:
Step 1: To reassemble the coupling halves, fit the spring with spring cap and spindle steering with PTFE-bushing. Press down the spindle steering and turn, to fix it in its position.
Step 2: To lock the spindle steering, Fit the screws into the given holes in the body and fixate the spindle steering by mounting the three locking screws. Use Loctite® 243 for locking the screws. Mount back the flat seal.
Step 3: Then replace the O-ring (pos.15) on the body with a new greased O-ring. Use only grease which is suitable for O-ring material. when replacing any spare parts, using original MannTek parts is necessary. For the break bolts, simply screw in the bolts into the intended position.
Step 4: To complete the reassembling, Set both halves onto each other and press them carefully together. The breaking pins should align to the bore holes in the second half. Screw on the nuts by hand until stop when halves are pressed together. Fasten it a little bit with a wrench, max 45 degrees. Screw on the second nut and lock the first one. Hold the first one with a wrench to avoid forces on the breaking bolt.
Take a look at the video down below to see it in person: