Repairing a solid roof is a little different from any other body panel. However, convertible tops throw a lot more issues into the mix. How do you get everything to line up? How do you get the top mechanism to work again? What do you do if the roll bar pops up? Here’s what it takes to repair a convertible top after an accident.
What Makes Up a Convertible Top?
A top is both part of the upholstery and a structural component. It needs to flex easily to fold down, but still create a tight seal when closed. To do this, the fabric is stretched over a metal frame using bolts, staples, springs, tacking strips and rivets. A liner is attached to the underside of the top. It does more than the headliner in a regular car: it also has to provide sound and thermal insulation.
The frame provides the underlying structural support, but it’s not part of the safety structure. Instead, automakers attach fixed roll bars behind the seats, or they fit hidden bars that deploy during a crash. Since there’s no roof to provide structural support, the frame and doors are beefed up to reduce chassis flex. These added supports increase complexity when performing auto body repairs.
Replacing the Top Fabric
Small tears in the top fabric can be sewn back together, but in most cases, it makes sense to replace the entire top.
Replacement starts with the disassembly of the back seats and trim pieces between the doors and the trunk. From there, the top can be separated from the frame.
There’s more to the top than just fabric. The edges of the frame have pieces of foam and rubber backing along the edges of the frame and wiring to the window for the defroster. At least some of these components will need to be replaced, either due to damage or aging.
New, pre-cut tops are readily available for most models, but they aren’t a perfect fit out of the box. Some spots may need to be trimmed or cut to fit the mounting brackets. This can be tricky since the old top stretches over time. The technician can use the old top as a pattern, but small adjustments need to be made to adjust for the tighter fabric. It takes just a small error in cutting to ruin the new top.
Automatic Top Repair
What about the frame? Small cars like the Mazda MX-5 usually have manual tops, so the frame just needs to be straight to work. Other cars have automatic tops that are easy to damage in an accident.
Older tops have electric motors that are adjusted manually to control the range of movement. Even a slight bend to the convertible top’s frame can keep the top from opening and closing. More recent designs have switches placed at each joint. Once each part of the top reaches the desired position, the switch cuts power to that section. New systems can also read changes in the power demand from each motor. If there’s a sudden spike in power draw, it tells the computer that there is an obstacle in the way.
Hydraulic systems use a pump to push fluid through hoses to a series of motors. When the pump is on, it pushes fluid through the system, spinning the motors. Fluid loss anywhere in the system can keep the top from opening and closing. These are sometimes paired with electric switches and sensors.
An accident can crimp or split wires and hydraulic lines, bend frame components and damage motors. Diagnosing and repairing these systems is one of the most difficult jobs on a car outside of engine and transmission repair. Once everything is working again, the frame is realigned, and the computer is recalibrated.
Convertibles pose a serious safety issue in a rollover accident. With no support for the back of the vehicle, the passengers will take the brunt of the impact. In the late 70s, convertibles were banned outright, leading to T-Top and Targa roof designs as a compromise.
Modern convertibles can provide the full open-top feel while maintaining safety by using hidden roll bars. When the safety system detects an imminent rollover, it fires an explosive charge that pushes the bar into the upright position. Like airbags, these bars are one use only. They need to be replaced entirely to restore the safety of the vehicle.
When You Need Trouble-Free Collision Repair, Go to Merton Auto Body
There’s a reason we’ve been a favorite of Lake Country residents for over 70 years. We’re an I-CAR Gold Class certified shop, and our technicians are ASE Certified. We’re also a preferred shop for most auto insurance companies. That means our collision repairs are consistent, fast and high quality, and we can handle the latest vehicles. Our shop is in Sussex, just a few miles from Pewaukee, North Lake and Lisbon.