108-904A LEGEND 4” T-550A CARTRIDGE & STEM ASSEMBLY

Fits Improved Flow 4” Frost-Free T-550A Sillcock

Repair your Legend T-550A frost-free sillcock quickly and easily with the 108-904A cartridge and stem assembly.
Designed for the Improved Flow version, this replacement restores smooth operation and eliminates leaks or drips.

✅ Key Features

• Direct OEM replacement for Legend T-550A Improved Flow 4” Frost-Free Sillcock

• Cartridge length: 7-3/4" (without handle) / 8-1/2" (with handle)

• Durable construction with one O-ring + two alignment tabs

• Straight inlet connection with round knurled wrench pad

• Easy identification: black disc with silver LEGEND lettering, patent marking Pat. 5.392.805 D527.797

• Precision-fit stem and seal for long-lasting performance

📊 Specifications Table

🔁 Cross Reference Table

🔍 Step-by-Step Identification Guide

Determine your sillcock model before ordering: T-550 (Original) or T-550A (Improved Flow). Both look similar externally, but internal cartridge designs differ and are not interchangeable.

🟢 Step 1: Check the Handle Identification Disc

✅ Quick Tip:

• Black disc with silver letters → likely T-550A

• Silver disc with black letters → likely T-550

🔩 Step 2: Check Handle Inlet Style (Quick Visual)

🧠 Tip:

• Straight inlet with round knurled pad → T-550A

• Tapered inlet with six wrench flats → T-550

⚠️ This is a visual guide. You still need to measure the cartridge to confirm.

📏 Step 3: Measure the Cartridge

After removing the stem assembly, measure the full length (tip to handle end):

🧭 Combine handle disc, inlet style, and cartridge length for definitive ID.

🧩 Quick Reference Comparison

⚠️ Final Check Before Ordering

✅ Order 108-904A if:

• Handle disc is black with silver lettering

• Inlet connection is straight with round knurled pad and includes the patent marking Pat. 5.392.805 D527.797

• Cartridge measures 7-3/4" (without handle) / 8-1/2" (with handle)

✅ Order 108-904AR if:

• Handle disc is silver with black lettering and includes only the phrase "Pat. Pend."

• Inlet connection is tapered with six wrench flats

• Cartridge measures 7-5/8" (without handle) / 8-1/2" (with handle)

🔧 Common Problems This Fixes

• Leaking or dripping frost-free sillcocks

• Handle difficult to turn or poor water flow

• Worn internal seals or O-rings

• Corroded or damaged cartridge connection

🛠️ Installation Overview

1. Turn off water supply.

2. Remove stem assembly.

3. Identify model using handle disc, inlet style, and cartridge measurement.

4. Install replacement cartridge with plumber’s grease on O-rings.

5. Reassemble handle and test for smooth operation.

🛒 Shopping Tips

• Check handle disc color, lettering, and patent markings.

• Verify inlet connection style (straight knurled pad vs. tapered six flats).

• Keep a wrench and plumber’s grease handy for installation.

❓ FAQ – Frequently Asked Questions

Q: How do I know if I need 108-904A or 108-904AR?
A: Use the Identification Guide: check handle disc, inlet style, and measure cartridge length.

Q: Can I install this myself?
A: Yes, both cartridges are designed for easy DIY replacement using standard tools.

Q: Are the cartridges interchangeable?
A: No — each cartridge fits its specific sillcock model. Always match by handle disc, inlet style, and cartridge length.