Pickup truck bed covers, also known as tonneau covers, are a great way to protect cargo and increase your truck’s gas mileage. However, over time the tailgate seals can become loose, causing leaks, wind noise, and debris to get into the truck bed. Loose seals should be repaired right away to prevent further damage.
Luckily, fixing loose tailgate seals is a straightforward process that can be done at home. In this article, we will walk through several methods for tightening and replacing tailgate seals to stop leaks on your tonneau cover.
What Causes Tailgate Seals to Become Loose on Tonneau Covers?
There are a few key reasons tailgate seals can come loose over time on a tonneau cover:
- Normal wear and tear: The seals are made of rubber or vinyl materials that slowly degrade from exposure to the elements. Over months and years of use, the seals dry out and lose their flexibility.
- Improper installation: If the seals were not installed correctly or bonded well initially, they may not form a tight seal from the beginning.
- Damage: Accidents, cargo shifting in the bed and hitting the tailgate, or trying to overstuff the bed can all cause the tailgate seals to come loose or become damaged.
- Improper latching/closing: If the tailgate is not properly latched and closed with the right amount of pressure, gaps can form in the seals over time.
How Can You Tell if Your Tailgate Seals are Loose or Leaking?
There are a few clear signs that the tailgate seals on your tonneau cover have become loose or damaged:
- Visible gaps or tears – Inspect the seals closely and look for any visible gaps, cracks, or tears in the seal around the perimeter of the tailgate.
- Water leaks – One of the most obvious indicators is finding water inside the truck bed after rain or washing. Loose seals will allow water to seep through.
- Wind noise – As you drive, wind noise from the tailgate area can indicate air and water are penetrating the seals.
- Dust/debris inside the bed – Finding dust or dirt that has blown into the bed also signals that the tailgate seals are not tight.
- Tailgate does not close flush – If the tailgate gaps open at the top or sides when closed, this points to seal damage.
How to Fix Loose Tailgate Seals on a Tonneau Cover
If you confirm that the tailgate seals on your tonneau cover are loose or leaking, here are several effective methods to fix them:
1. Replace the Seals
Replacing the tailgate seals is the most thorough and permanent solution. Here is the process:
- Purchase a tailgate seal replacement kit specifically designed for your cover. Bring your cover to an auto parts store or check the manufacturer’s website for the proper replacement parts.
- Remove the old seals completely by pulling or prying them out of the tailgate trim using a flathead screwdriver, plastic pry tool, or seal removal tool.
- Thoroughly clean the channel where the new seals will be installed. Remove any old adhesive, dirt, or debris.
- Apply rubbing alcohol to clean and prep the area. Allow it to dry completely.
- Test fit the new seals and trim to length if needed. Apply adhesive primer/activator to the channel and seals.
- Insert the new seals starting at one end, pressing firmly into the channel as you go. Ensure proper alignment as you work your way around the tailgate.
- Allow the adhesive to cure for at least 2-4 hours before reinstalling the cover. Check for full adhesion by running your finger along the seal.
Replacing worn seals will provide a perfect, watertight seal around the tailgate again. This restores the cover’s performance and protects your truck bed.
2. Adjust the Latch Pins
If the existing seals still have good condition but the tailgate is slightly misaligned, adjusting the latch pins can tighten the closure.
- Release both latch pins from the catches and lower the tailgate about 1/4 inch.
- With the tailgate supported, gently tap the latch pins inwards toward the center using a hammer and punch. Move them in increments of 1/16 to 1/8 inch at a time.
- Test closing the tailgate in between adjustments to see if the seals are tightening up against the bed sides and eliminating gaps.
- Carefully readjust until the latch pins hold the tailgate flush against the seals for a tight fit. Do not over-tweak the latch pins.
Aligning the tailgate position with the latch pins can often improve the seal contact without replacements. But it does not fix damaged or severely deteriorated seals.
3. Use Silicone Spray as a Temporary Fix
For a quick and easy emergency fix, silicone spray can help the seals grip and adhere better to temporarily stop leaks:
- Clean the seals and tailgate trim thoroughly first with rubbing alcohol.
- Spray silicone liberally along the top and side seals, targeting any visible gaps or problem areas.
- Allow the silicone to penetrate the seals for 2-3 minutes.
- Close the tailgate and latch it tightly.
The silicone lubricates the seals so they compress and conform better to fill gaps around the tailgate. This can provide a temporary improvement until you can replace damaged seals.
4. Install a Tailgate Gap Cover
For an inexpensive, foolproof solution, install a tailgate gap cover:
- These covers slip over the top and sides of the tailgate to cover any gaps or uneven seal surfaces.
- They are designed specifically to prevent bed leaks through the tailgate area.
- Brands like Extang and UnderCover make gap covers to match most tonneau models.
- Simply clean the tailgate, peel the adhesive backing, and press the gap cover firmly into place along the top and sides.
The gap cover acts as a second barrier to block moisture and dust. Just be sure to carefully follow the manufacturer’s instructions for proper installation.
5. Consider a Complete Seal Replacement Kit
For older tonneau covers with extensive seal damage, a complete seal replacement kit is the best solution.
These kits include:
- Fresh tailgate seals
- Side seals along the bed rails
- Front header seals
Replacing all the seals restores the cover to like-new condition. It’s a more extensive project but gives you reliable seals and optimal performance.
Brands like CIC and Crevier offer seal kits for most tonneau models. Carefully follow all included instructions for full disassembly, cleaning, adhesive use, and proper seal installation when replacing the entire seal system.
Tips for Making Tailgate Seals Last Longer
To maximize the lifespan of your tonneau seals and prevent frequent loose seal repairs, keep these maintenance tips in mind:
- Inspect seals regularly and re-adhere small gaps immediately with silicone sealant.
- Keep seals clean by washing the cover and treating with UV protectants.
- Avoid overloading the truck bed which can stress and damage seals.
- Always ensure the tailgate closes, latches, and seals fully before driving.
- Lubricate the seals 2-3 times per year with UV resistant lube made for tonneaus.
- Park in the shade whenever possible to limit seal sun exposure.
- If driving in very dusty or muddy conditions, consider adding a disposable tailgate gap cover.
- Adjust latches over time to account for any tailgate settling and alignment changes.
Proactive care and maintenance will keep your tonneau cover seals flexible and air-tight for years before repairs are needed. But even the best cared for seals will eventually fail and need replacement.
When to Call a Professional for Tonneau Cover Seal Repairs
While the above fixes can be done DIY on standard vinyl or rubber seals, some cases may require a professional:
- If seals are completely torn off or missing sections, a shop repair may be needed.
- Covers with specialized seal designs may need dealer installation.
- For hard folding covers or retractable covers, the complex design often requires expert repair.
- If adjusting latches does not improve the seal, the source of the problem may be more complicated.
- If you don’t have the time or tools to complete the full seal replacement process.
Most truck accessory shops can replace seals on tonneau covers. They have the skills and materials to properly seal the tailgate area and prevent leaks.
For warranty coverage, dealers may provide free seal repairs depending on cover age and condition.
Maintain Truck Bed Protection with Proper Tailgate Seals
Loose, leaking seals around the tailgate of your tonneau cover should not be ignored. But luckily this is one of the simplest repairs you can complete yourself to keep your cover performing its best.
Pay attention for any signs of seal failure, and promptly address gaps, tears, or leaks using the solutions outlined. With properly sealing tailgate weatherstripping, you can rely on your cover to protect your truck bed from the elements for many miles to come.
