A tonneau cover popping open while driving can be a dangerous and frustrating situation. Thankfully, there are several ways you can troubleshoot and fix this problem. In this article, we’ll explore the common causes of tonneau covers coming undone and provide solutions to secure your cover and prevent it from opening unexpectedly on the road.
Ensure Proper Installation
One of the most common reasons a tonneau cover pops open is improper installation. Make sure that your tonneau cover is properly installed. If it is not securely fastened, it can cause the cover to come undone while driving.
Check the following:
- Are all clamps, bolts, and snaps tightened down completely? Go back and tighten any loose hardware.
- Are the rails aligned properly and securely attached to the bed? Misalignment can put stress on the cover.
- Does the cover sit flush with the bed or are there gaps? Gaps can allow wind to get underneath and lift the cover.
- Are all weather sealing strips and gaskets installed correctly? Seals prevent air from entering underneath.
Taking the time to install your tonneau cover precisely according to the manufacturer’s directions will help keep it locked down while driving. If it is not securely fastened, it can cause the cover to come undone while driving.
Check the Latch
Incorrect locking of the latch can cause the tonneau cover to pop open. Ensure that the latch is secured in the right way. On roll-up tonneau covers, make sure the clamps are aligned properly over the rails. For folding covers, ensure the latches are fully engaged and snap securely into place.
If the latch pops out when it is not properly locked, press down on the cover to fully lock the latch. Putting downward pressure as you lock the latch can help it seat correctly. You may need to adjust the latch strike or keeper to get a tighter fit if it won’t stay locked.
Check for Size Compatibility
If your tonneau cover is too big or too small for your truck’s bed, it may not fit properly and could result in the cover popping open. Ensure that you have the correct dimensions for your truck’s bed before purchasing a tonneau cover.
Measure the inside length and width of the bed to find the perfect fitting cover. An oversized cover that hangs over the bed sides or an undersized one that doesn’t reach to the tailgate can both come loose while driving.
Consider Temperature Changes
Temperature changes can cause the vinyl of the tonneau cover to shrink or expand. If the cover was not properly secured when the temperature changed, it may not have clicked into place.
Make sure to secure the cover properly in different weather conditions. In cold weather, close it fully to account for vinyl shrinking in lower temps. In hot weather, make sure to lock it despite vinyl expansion.
Inspect All Hardware
Do a thorough inspection of all hardware including clamps, snaps, hinges, latches, and rails. Look for the following:
- Broken or cracked clamps or latches: Replace any damaged hardware that isn’t closing securely.
- Rusted or corroded parts: Clean and lubricate or replace rusted parts as needed.
- Loose or worn latch springs: Tighten or replace worn out springs so the latches close tightly.
- Stripped or crossed threads on bolts: Fix or replace any bolts with compromised threads.
Fixing or replacing any compromised or defective hardware can help eliminate tonneau openings.
Adjust Striker Plates
If latches seem loose or don’t fully close, adjusting the striker plates may help. The striker is what the latch hooks into to close the tonneau.
Use a screwdriver to shift it into a position that allows the latch to close tighter. On a roll-up cover, move the strikers on the clamps. For a folding cover, adjust the strikers along the bed rails. Make small adjustments until the perfect fit is found.
Add Latch Securing Devices
For added security, there are aftermarket tonneau latch securing products that prevent latches from popping open.
- Latch straps: These are straps that loop under the latch and over the cover, stopping the latch from releasing. Most attach with velcro or snap closures.
- Latch locks: Small locks that block the latch from opening when engaged. They usually come with two keys and are an affordable security add-on.
Add Rail Clamps
Rail clamps are another way to reinforce a tonneau cover and keep it from opening while driving. The clamps sandwich the side rails to the bed, limiting rail movement that can shift the cover.
On roll-up covers, rail clamps keep the rails from separating from the bed. On folding covers, they stop the rails from twisting which leads to cover popping open. Install them evenly spaced along the rails for maximum hold.
Adjust or Replace Gas Struts
For folding tonneau covers, worn out or incorrectly adjusted gas struts can prevent the cover from staying closed. Gas struts gradually lose pressure and their lifting capability weakens over time.
Replace gas struts that appear worn every 2-3 years. Also check the strut mounting brackets for cracks and resecure or replace if needed.
Make sure the struts have the proper tension to hold up the cover but not so much that closing is difficult. Adjustable gas struts can be tightened or loosened to the perfect pressure.
Replace Seals and Weatherstripping
Over time, the seals and weatherstripping on a tonneau cover can dry out, crack, or separate from the rails/bed. Gaps from deteriorated seals allow wind to rush underneath and force the cover open.
Inspect all the seals including side rail seals, tailgate seals, and foam filler strips. Replace any that are damaged or missing. Use seal adhesives like 3M weatherstrip tape to resecure loose sealing.
Proper application of fresh seals/weatherstripping eliminates wind entry and cover openings. Most manufacturers sell replacement seals if the originals become defective.
Adjust Side Rail Alignment
If the rails on each side of the bed don’t align correctly, it can tweak the cover and cause popping open while driving.
Check that the rails are parallel and even in height. If they are crooked or uneven, the cover won’t sit flat. Loosen the rail clamps and shift the rails until they align correctly with the contour of the truck bed.
Equal rail height and orientation is key for smooth cover operation and keeping it sealed tight in transit.
Tighten Down Bows
For soft roll-up tonneau covers, loose or broken bows can lead to the vinyl billowing up and tearing away from the rails. The bows are the crossbars inside the roll-up vinyl that provide shape and support.
Do an inspection and tighten down any bow clamps/brackets that are loose. Also check the bows themselves for cracks and replace any broken ones.
Keep the bows in good condition and firmly attached so the vinyl stays taut instead of flapping up.
Close Tailgate First
Sometimes the sequence of closing the tailgate and then the tonneau cover makes a difference in it staying shut.
Try closing the tailgate before locking down the tonneau cover. This takes any slack out of the system. The tailgate pushes up and seals the cover before you then secure the cover latch.
On some truck beds, closing tailgate last inadvertently lifts the cover slightly and leaves play for wind to get underneath. Closing it first means the cover sits flat when locked.
Add Tailgate Seal Kit
Most tonneau covers come with a tailgate sealing pad, but for an even tighter seal you can install a full tailgate seal kit. These kits provide a weatherproof gasket seal around the entire tailgate opening when the cover is closed.
The extra-thick sealing minimizes air intrusion from the tailgate area. This prevents wind from pressurizing under the cover and forcing it open.
Adjust Side Rail Brackets
For hard folding covers, loose or misaligned rail brackets can lead to cover popping open over time. When the brackets shift, it tweaks the rails and prevents proper cover closure.
Inspect the rail brackets that attach the rails to the bed for any movement or gaps. Tighten down any loose bracket fasteners securely. You may need to shim or adjust the brackets to realign the rails if they have shifted out of position.
On folding tonneau covers, dry hinges can cause resistance when opening and closing the cover. This resistance can potentially lift the unsecured panels or distort the cover.
Keep the hinges lubricated with a light oil or spray lubricant according to the manufacturer’s directions. Most recommend lubricating every 3-4 months as routine maintenance.
Lubricating the hinges keeps them moving freely and the covers folding/unfolding smoothly without added pressure lifting or skewing the panels.
Adjust Latch Cables (Roll-Up)
On roll-up tonneau covers, the latching cables that run along the rails commonly need adjustment after some use. When they are too loose or too tight, it affects the latching security.
Follow the manufacturer’s guidelines to adjust the cables so they have just the right tension. They should be taut but not overtightened. Adjustments are usually made via turnbuckles located along the underside.
Properly tensioned cables keep the rail latches closing evenly and firmly to prevent unwanted openings while driving.
Add Roll Stops
For any standard roll-up tonneau cover, inexpensive roll stops can be added to keep the cover from unrolling and blowing open uncontrollably.
Roll stops slide into the rails and physically stop the cover from opening more than a few inches. They prevent it from unwinding rapidly should the latches fail for any reason.
Roll stops are an easy precautionary measure to limit how far your roll cover will open if shook loose while driving.
Velcro Strips for Soft Covers
For soft roll-up or folding tonneau covers with vinyl panels, velcro strips can be used to reinforce loose spots prone to flying open.
Are certain areas or seams coming loose where wind catches underneath? Apply industrial strength velcro strips along the vulnerable seams or edges. The velcro keeps everything held down tightly.
Strategically placed velcro strips along the cover seams and attachment points help prevent wind intrusion and the cover working loose.
Check for Warped Bed
If a truck bed is significantly warped or bent, it can prevent the tonneau cover from sitting flush and sealing tightly. Gaps from a warped bed allow the cover to pop open while driving.
Inspect your truck bed for any areas that are abnormally concave or convex. Also check for proper bed alignment with the cab. Excessive truck bed warping or misalignment requires professional correction to ensure proper tonneau cover function.
Add Securing Straps
A simple way to reinforce a tonneau cover and keep it from opening while driving are tarp-style securing straps. Attach one side of the strap along the bumper or tie-down rings. Run the strap over the cover and connect to the opposite side.
Loosely tighten the straps just until any gaps disappear between the cover and bed. Don’t crank them down tightly. Arrange the straps evenly spaced down the length of the cover.
Securing straps offer inexpensive insurance against your cover opening unexpectedly while driving. They stop wind lift and reduce any shimmying motion.
Fixing a tonneau cover that repeatedly pops open during transit requires investigating the underlying causes and implementing the proper solutions. While frustrating, it is a common problem that can be corrected with some toubleshooting and adjustments.
Be sure to properly install the cover, inspect and fix any defective hardware, and realign components as needed. Supplement with reinforcing devices like rail clamps, straps, velcro, and weathersealing to prevent air intrusion. Keep components adjusted and lubricated for smooth function.
With the right repairs and preventative measures, you can permanently solve the problem of an opening tonneau cover. Invest some time upfront to ensure it latches securely every trip. Then enjoy the benefits of a tonneau cover that stays closed exactly where it belongs while out on the open road.