Replacing a DPF Weld Bung

The Set Up:

It happens more often than you might think. You or your customer is performing a routine sensor replacement on a heavy-duty diesel vehicle’s aftertreatment system. The old sensor just won’t loosen and in the process of all the heating and hammering, it happens. The bung (aka sensor port) gets damaged – usually the threads are wrecked.

After a few choice words and some deep breaths, the questions start forming in your mind. Now what? How much is this going to cost to fix? Do I need to replace the whole, damn filter?

The answer to these questions might not be what you’re thinking.

We’re going to go through your options and cover the basics of replacing a DPF Weld Bung. Yes, not only is it possible, but with the right tools and know-how, a broken weld bung can be swapped out with a new one. Whether you do it yourself or have a trusted diesel technician/mechanic do it is up to you.

Small Part, Big Savings:

While the process of bung replacement can be time-consuming and tricky, it likely will be far cheaper than getting a new filter (be that a DPF, DOC, One Box, etc). Weld bungs for this application generally run about $25 plus tax and shipping. Replacing a weld bung will also involve some experience and expertise in metalwork and welding. But with a new filter costing anywhere from $700 to $5,000 and up, it’s worth considering this option.

Reminders & Disclaimers:

As with any repair associated with heavy-duty trucks – proper safety equipment, training, specialized tools, and equipment are a prerequisite. A healthy dose of common sense goes a long way when dealing with this type of repair as well.

Remember: Safety should always be of top importance when working on a heavy-duty vehicle’s exhaust system. Put on/use appropriate protective gear, including gloves, safety glasses, welding mask, a respirator, hearing protection, etc.

Let’s get started…

SET-UP & TOOL SELECTION:

BROKEN BUNG REMOVAL:

• Assess the damage: Determine the extent of the damage to the bung and surrounding area.
• Drilling and extraction: If the bung is broken off flush, carefully drill a hole in the center and use an extractor to remove the remaining pieces.

PRO-TIP #1: To remove the broken bung, it is often more effective to employ a hole saw. Select a hole saw blade with a diameter slightly larger than the bung. Carefully cut around the broken bung to remove it, this helps make a clean hole for welding the replacement bung.

NEW BUNG INSTALLATION:

• Prep the area: Thoroughly clean the welding area to remove debris and ensure a good bond.
• Position the new bung: Ensure the bung fits snugly and aligns correctly and then clamp/tack weld into place. Double-check alignment and position before fully welding the bung.
• Weld it: Use appropriate welding techniques and filler material for the DPF material. Consider using a TIG welder for precision. Weld around the entire circumference to ensure a strong, leak-free connection.
• Check your work: Check for any gaps or imperfections in the weld and re-weld if necessary.
• Cool Down: Allow the weld to cool completely before proceeding.

FINISHING UP:

• Thread chasing: Clean and chase the threads in the new bung to remove any debris.
• Install sensor: Be sure to apply that anti-seize to the sensor and carefully tighten it into the bung. Note: all REP sensors come with a tube of anti-seize.
• Reassemble: Reinstall the exhaust components and secure all connections.
• Double Check: Start the vehicle and check for gas leaks around the new weld bung and other components affected by this repair.

PRO-TIP #2: Do not forget the anti-seize! This step is easy to skip over, but will help prevent this whole broken bung thing from happening again. Especially if the truck operates in highly corosive areas such as in colder climates where they often salt the roads in winter.

MORE HELPFUL ADVICE:

• Don’t rush it: Taking your time to do things right saves time in the end.
• Protect the work area: Use “heat shields” of some sort to protect nearby components from heat damage & sparks.
• Test for leaks: After reassembly, check and re-check for exhaust leaks. Don’t skip this step. You don’t need the truck to start throwing codes down the road due to a leak somewhere.
• Consider professional help: If you encounter problems, take a break and consider getting help from an experienced/trained mechanic or welder.

By following these steps and being careful, you can increase your chances of fixing the DPF weld bung without too many issues.

Read our recent article on A Guide to Identifying Weld Bungs (don’t worry, it has nothing to do with pronouns) and while you’re there get our free Weld Bung Guide infographic.

Still not sure, or want to double-check? No problem. Give us a quick phone call, or email.

Redline Emissions Products is the industry leader in simplifying the diesel emission system.

Browse our website to learn more about our extensive range of aftertreatment products, equipment, & services. And don’t forget our Cross Reference Tool for looking up emissions parts.

For inquiries or more information on our aftertreatment parts, DFP Cleaning equipment, or how to become an authorized REP distributor, feel free to contact us. We are here to assist you and provide the support you need every step of the way.

Want to find out about becoming a Redline Emissions Products® dealer? Contact Anthony Soto, National Sales Manager for REP to find out more. Call 888-295-4670

Need Tech Support or need help troubleshooting a DPF problem? No problem! Contact REP Support at 1-888-564-4209

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