How to Install Trunk Gaskets

Applies to: Molded trunk gaskets with distinct profiles—typically featuring a lip section and tail sections that wrap around the trunk opening.

What You'll Need

• 3M Black Weatherstrip Adhesive (GL-11)
• Sharp pruning shears or scissors
• Spring clamps (Stanley brand or similar)
• Plastic scraper
• Sandpaper (if repainting)
• Clean rags and rubbing alcohol
• Nitrile gloves (GL-10)

💡 Pro Tip: Removing the trunk lid makes installation much easier—especially for cleaning and accessing corners.

Understanding Your Trunk Gasket

Most trunk gaskets have two distinct profiles:

The joint (where tail sections meet) can be centered or offset—both work fine.

Method 1: Centered Joint (Recommended)

This places the splice joint at the center bottom—the least visible location.

Steps:

1. Trial-fit the gasket completely without adhesive
2. Note where lip section and tail sections are located
3. Mark the center of trunk opening (usually directly above lock cylinder)
4. Start in lower right corner where lip section begins
5. Apply adhesive and work slowly toward back glass
6. Clamp corners as needed to hold
7. DO NOT pull the gasket tight! Let it lay naturally.
8. When lip section is complete, position the tails
9. Cut tails, allowing 1/8" extra at the joint
10. Apply adhesive to both cut ends and butt together firmly

Method 2: Factory-Style Offset Joint

This replicates how the factory originally installed the gasket—the joint may be ½" to 2" off-center.

Steps:

1. Trial-fit the gasket completely
2. Start in either lower corner where lip and tail sections meet
3. Cement one tail first, then continue with lip section around opening
4. Clamp as needed
5. Bring remaining tail across the bottom
6. Butt into installed tail—allowing 1/8" extra
7. DO NOT pull gasket tight!

Both methods work equally well. Centered joint looks cleaner; offset is "factory correct" for some vehicles.

Key Tips for Success

DO:

✅ Trial-fit the entire gasket before applying any adhesive
✅ Allow 1/8" extra material at the splice joint
✅ Use clamps to hold corners while adhesive sets
✅ Work slowly—rushing causes misalignment
✅ Clean trunk lip thoroughly before starting

DON'T:

❌ Pull or stretch the gasket—it should relax into position
❌ Apply adhesive to the entire gasket at once—work in sections
❌ Close trunk until adhesive has set (minimum 1 hour)

Surface Preparation

1. Remove old gasket completely
2. Scrape off all old adhesive
3. Sand any rust spots
4. Prime and paint bare metal if needed
5. Clean with rubbing alcohol
6. Let dry completely before installing new gasket

A plastic trim tool helps remove old gasket material without scratching paint.

Troubleshooting