Delta Faucet RP84385-1.2 Replacement Parts Guide (2024)

Is your Delta faucet dripping, leaking, or just not turning smoothly? You’re not alone—over 60% of U.S. homeowners deal with minor plumbing issues each year, and worn-out cartridges like the Delta Faucet RP84385-1.2 are a common culprit. The good news? Replacing this part is often simpler (and cheaper) than calling a plumber. In this guide, we’ll walk you through everything you need to know about the Delta Faucet RP84385-1.2 Delta Plumbing Replacement Parts, from compatibility to installation—so you can restore your faucet’s performance in under an hour.

What Is the Delta Faucet RP84385-1.2?

The Delta Faucet RP84385-1.2 is a genuine OEM (Original Equipment Manufacturer) replacement cartridge designed specifically for Delta single-handle bathroom faucets with 1700-series or 1700T-series trim kits. This cartridge controls both hot and cold water flow and temperature through a single lever.

Unlike generic knockoffs, the RP84385-1.2 features Delta’s DIAMOND™ Seal Technology, which uses a ceramic disc valve with diamond-like carbon coating. According to Delta, this design lasts up to 5 million uses—roughly 10 times longer than traditional cartridges.

💡 Pro Tip: Always verify your faucet model before purchasing. The RP84385-1.2 does not fit kitchen faucets or multi-handle designs.

How to Know If You Need the RP84385-1.2 Replacement

Common signs your cartridge needs replacing include:

• Persistent dripping even when the handle is fully off
• Difficulty turning the handle (stiff or gritty motion)
• Inconsistent water temperature (sudden hot/cold surges)
• Visible mineral buildup around the base of the handle

If you own a Delta bathroom faucet installed between 2005 and 2020, there’s a high chance it uses this cartridge. Check the model number on the underside of the spout or inside the handle cap.

Step-by-Step: Replacing Your Delta RP84385-1.2 Cartridge

Replacing this part takes 20–40 minutes and requires only basic tools. Follow these steps carefully:

Tools You’ll Need:

• Adjustable wrench
• Phillips and flathead screwdrivers
• Needle-nose pliers
• Towel or rag
• White vinegar (for descaling, if needed)

Step 1: Shut Off Water Supply

Turn off both hot and cold water valves under the sink. Open the faucet to relieve pressure and drain residual water.

Step 2: Remove the Handle

• Pry off the decorative cap on top of the handle (use a flathead screwdriver).
• Unscrew the Phillips screw underneath.
• Gently pull the handle straight off. If stuck, wiggle it slightly—do not force it.

Step 3: Extract the Old Cartridge

• Use needle-nose pliers to remove the retaining clip (a small metal ring around the cartridge stem).
• Grasp the cartridge stem and pull straight out. If corroded, soak it in ½ cup white vinegar for 10 minutes to loosen mineral deposits.

Step 4: Install the New RP84385-1.2

• Align the flat sides of the new cartridge with the faucet body grooves.
• Push it in firmly until fully seated.
• Reinstall the retaining clip until it clicks into place.

Step 5: Reassemble & Test

• Reattach the handle and screw.
• Replace the cap.
• Turn water supply back on.
• Test for leaks and smooth operation. Run water for 2–3 minutes to flush debris.

⚠️ Warning: Never overtighten screws or clips—this can crack the cartridge housing and cause new leaks.

RP84385-1.2 vs. Other Delta Cartridges: What’s the Difference?

Not all Delta cartridges are interchangeable. Here’s how the RP84385-1.2 compares to similar models:

Using the wrong part can cause leaks or damage your faucet. When in doubt, consult Delta’s official Faucet Parts Finder .

Where to Buy Genuine Delta RP84385-1.2 Parts

Avoid counterfeit parts on third-party marketplaces. Genuine Delta cartridges come in sealed packaging with a Delta logo and part number clearly printed.

Trusted Retailers:

• Home Depot
• Lowe’s
• Amazon (sold by Delta or authorized dealers)
• DeltaFaucet.com

Average price: $18–$25. While generic versions cost less, they lack DIAMOND™ technology and often fail within months.

For more on plumbing standards and materials, see Wikipedia’s overview of faucet mechanisms .

Common Mistakes to Avoid

Even experienced DIYers make these errors:

1. Skipping the water shutoff → Causes flooding under the sink.
2. Forcing the handle off → Cracks the stem or escutcheon.
3. Ignoring mineral buildup → Leads to premature wear of the new cartridge.
4. Using pipe sealant on the cartridge → Not needed; the O-rings create the seal.

A 2022 study by the Plumbing-Heating-Cooling Contractors Association found that 73% of DIY faucet repairs fail within 6 months due to incorrect part selection or installation errors.

FAQ Section

Q: Does the Delta RP84385-1.2 work with touchless or smart faucets?
A: No. The RP84385-1.2 is for manual single-handle faucets only. Touchless models (like Delta Touch2O) use electronic solenoid valves and require different parts.

Q: Can I clean the old cartridge instead of replacing it?
A: Sometimes—but only if it’s clogged with minerals, not worn out. Soak it in vinegar for 30 minutes, scrub gently with a toothbrush, and rinse. However, if the ceramic discs are scratched or chipped, replacement is necessary.

Q: My faucet still leaks after installing the new cartridge. What’s wrong?
A: Check the O-rings on the cartridge stem—they may be damaged or misaligned. Also ensure the retaining clip is fully seated. If the leak persists, the faucet body itself might be cracked.

Q: Is the RP84385-1.2 covered under Delta’s warranty?
A: Yes! Delta offers a lifetime limited warranty on all DIAMOND™ Seal cartridges for the original purchaser. Keep your receipt and register your product on their website.

Q: How often should I replace this cartridge?
A: Under normal use, every 10–15 years. However, in hard water areas (high mineral content), consider replacement every 5–7 years to prevent buildup-related failure.

Q: Can I use this part in a kitchen faucet?
A: No. The RP84385-1.2 is exclusively for bathroom faucets. Kitchen models (like the 1900-series) use larger cartridges such as RP60400.

Conclusion

The Delta Faucet RP84385-1.2 Delta Plumbing Replacement Parts offer a reliable, long-lasting fix for common bathroom faucet issues—saving you time, water, and costly plumber visits. With Delta’s DIAMOND™ Seal Technology and straightforward installation, this cartridge is a smart investment in your home’s functionality.

If this guide helped you avoid a plumbing headache, share it with a friend on Facebook, Pinterest, or Twitter! And don’t forget to check your other faucets—preventive maintenance today means fewer leaks tomorrow.

Got questions? Drop them in the comments below—we’re here to help!