Mistake #1: Not Allowing Break-In Time
⚠️ THE #1 CAUSE OF "SEAL TOO THICK" COMPLAINTS
The Problem:
You install new weatherstripping, and now your door requires excessive force to close—or won't latch at all. You assume the seal is too thick or defective.
The Reality:
Metro's SUPERsoft sponge rubber is intentionally manufactured slightly larger than the original compressed seal. This is by design—it ensures a proper seal once installed.
The Fix:
- Give it time. New rubber needs a "break-in period" (also called degassing) of 3-7 days to compress and conform to your door/trunk opening.
- Close the door normally (firmly, but don't slam) and leave it closed
- Within days, the rubber will "memorize" its compressed shape
- Some restorers use a heat gun on LOW to speed this process—close the door and apply gentle heat to the seal area
Do NOT adjust hinges or latches immediately. Give the seal time to break in first.
Mistake #2: Skipping the Dry-Fit
The Problem:
You apply adhesive, install the seal, and discover it's misaligned, wrong-side-up, or doesn't fit the contour. Now you have a glued-on mess.
The Fix:
ALWAYS dry-fit first. Lay the seal in place without any adhesive to verify:
- Correct orientation
- Proper length
- Smooth alignment without bunching
- Clip holes align with mounting holes
- Corner sections reach without stretching
Only after confirming fit should you apply adhesive.
Mistake #3: Ignoring Red and Green Dot Markers
The Problem:
Molded door seals look symmetrical but aren't. Installing the wrong side results in poor fit, gaps, and seal failure.
The Fix:
Look for colored dots on your molded seals:
- 🔴 Red Dot = Driver Side (Left)
- 🟢 Green Dot = Passenger Side (Right)
Match the dots to the correct side of the vehicle. When in doubt, compare the seal profile to your original or dry-fit both options.
Mistake #4: Using Adhesive ONLY (When Clips Exist)
The Problem:
Your seal has pre-installed clips OR corresponding clip holes, but you rely entirely on adhesive. Over time, the seal pulls away between clip points.
The Fix:
Use BOTH clips AND adhesive:
- Insert all clips into their mounting holes
- Apply small dots of 3M Black Weatherstrip Adhesive (GL-11) between the clips
- This prevents the rubber from gapping or pulling away in the un-clipped sections
Clips provide mechanical hold; adhesive fills the gaps.
Mistake #5: Poor Surface Preparation
The Problem:
Your new seal won't stick, keeps peeling off, or falls off within weeks.
The Cause:
You installed over:
- Old adhesive residue
- Oil, grease, or silicone
- Dirt, dust, or loose paint
- Moisture
The Fix:
Proper prep is mandatory. See our complete Surface Preparation Guide, but in summary:
- Remove ALL old adhesive (100%)
- Clean with isopropyl alcohol
- Let dry completely
- Address any rust
- Apply adhesive to clean, dry surface at 60°F+
Mistake #6: Stretching the Seal to Fit
The Problem:
Your seal seems slightly short, so you stretch it to reach. Within days/weeks, the stretched rubber contracts, creating gaps at corners or joints.
The Fix:
Rubber has memory. If you stretch it, it will eventually shrink back.
- If the seal is genuinely too short, contact Metro—you may have the wrong part
- For proper fit, the seal should lay naturally with minimal tension
- Slight compression at corners is acceptable; stretching is not
- Allow the seal to "relax" at room temperature before installation if it was tightly coiled in shipping
Mistake #7: Closing the Door Immediately After Gluing
The Problem:
You apply adhesive, install the seal, immediately close the door, and the seal shifts or smears before the adhesive sets.
The Fix:
Allow proper cure time:
- Initial tack: 10-15 minutes before carefully closing
- Full cure: 24-48 hours before normal use
- Don't slam doors during the cure period
- Keep trunk/hood propped slightly open if possible
For 3M Black Weatherstrip Adhesive (GL-11), optimal cure time is 24 hours at 70°F.
Quick Reference: Installation Success Checklist
| Step | ✓ |
|---|---|
| Surface prep complete (no old adhesive, clean, dry) | ☐ |
| Dry-fit performed before adhesive | ☐ |
| Correct seal for correct side (check dots) | ☐ |
| Clips installed + adhesive between clips | ☐ |
| Not stretched to fit | ☐ |
| Allowed initial tack time before closing | ☐ |
| Will allow 3-7 day break-in period | ☐ |
Complete this checklist and you'll avoid 90% of installation problems.
Need More Help?
For best results, use our Complete Installation Kit (GLK-1) which includes professional-grade adhesive, trim tools, and everything you need for a successful weatherstrip installation.