764-04077B Lawn Mower Grass Bag Fits for MTD 21" Push Lawn Mower 764-04077A 764-04077 (Only Grass Bag)

What It Is

This is a replacement grass bag for MTD 21-inch push mowers, designed to catch clippings during mulching or bagging. It replaces OEM part numbers 764-04077A and 764-04077, and is a direct fit for MTD, Cub Cadet, Troy-Bilt, and Yard Machines models with a 21-inch steel deck.

Fitment & Compatibility

• Deck size: Only fits 21-inch push mowers (not self-propelled or riding mowers).
• OEM cross: Replaces MTD 764-04077, 764-04077A, 764-04077B, and 764-04077C.
• Check your model: Confirm your mower’s model number (stamped under seat or on deck) against MTD’s compatibility list—common fits include MTD 11A-020S, 11A-021S, and Cub Cadet SC221.
• Measurements: Bag is roughly 18" x 12" x 10" (L x W x H). Measure your mower’s bag attachment points (hooks or clips) to ensure a snug fit—some aftermarket bags may sag if the frame isn’t identical.
• Material: Heavy-duty woven polypropylene, similar to OEM. Not compatible with older MTD bags that used a different clip style (pre-2010 models).

Key Things to Know

• Installation: Tool-free—slides onto mower’s rear bag mount. Ensure the bag’s plastic clips snap fully into the mower’s brackets; loose fit can cause bag to detach during use.
• Durability: Woven material is puncture-resistant but not waterproof. Avoid leaving it in rain—prolonged moisture can weaken seams.
• Capacity: Holds roughly 1.5 bushels (about 1.5 standard trash bags of clippings). Works best with dry grass; wet clippings will clog the bag chute faster.
• Gotcha: Some users report the bag’s zipper (if present) can jam if overfilled. Empty before it’s completely full to prevent tearing at the seam.

Should You Buy It

Buy this bag if you own a compatible MTD 21-inch push mower and need an affordable, direct-fit replacement for a worn or torn OEM bag. It’s a solid value at $26.69, but skip it if your mower uses a different bag mount style (e.g., side-discharge or older hook system)—measure first to avoid returns. For occasional residential use, it’ll last 2–3 seasons with proper care.