Today's convertible tops still incorporate many of these same basic designs and mechanisms but with plenty of refinements that make raising and lowering the top far easier for the driver and provide a better fit for the top. All this creates a more aesthetic profile for the vehicle.
Consider the 2009 Chrysler Sebring. When a driver lowers its top, the windows drop down and the rear trunk lid lifts up. The top then folds into the trunk compartment, and the trunk lid closes (see Fig. 1).With all these advancements come plenty of repair challenges. Simply spotting damage to a top can be extremely difficult. Many shops lack the training and experience to handle a convertible repair properly. According to R.L. Polk and Co., in 2007, convertibles accounted for a little less than 2 percent of the light vehicle market. Depending what area of the country your shop operates, you may see few of these vehicles.
Even if a ragtop is a rare sight in your shop, you still need to be prepared to deal with one. Use the following seven steps to help you identify potential problems, diagnose damage and conduct repairs on a convertible.
STEP 1: Address all potential electrical problems with the proper methods and tools
Because many of the top's core components are electronic, damage to them can escape visual inspection easily. Modern convertibles use sensors to monitor when the top is unlatched and what position it's in. A control module continually tracks every step of the top's movement, along with monitoring other factors such as the outside temperature and the car's speed.
When one of these components fails or is damaged in a collision, most automakers use a default that prevents the automated convertible mechanism from functioning. (When the top won't open automatically, most of these vehicles have an emergency method for moving it.) Some convertibles, however, require special procedures and scan tools to identify problems or the source of problems. For example, it may be necessary for a repairer to go through an initialization process to be able to identify what stage the top is in currently.
You'll also need to address the electric components that work with the hydraulics. Driving the mechanisms in a convertible are a number of hydraulic cylinders and lines and a few electric motor-driven latches. Some cylinders possess internal hall effect sensors that monitor movement. A scan tool is required to determine if they are working properly. These cylinders can be located anywhere from the front header bar to the trunk, depending on how the top is designed.
You'll need to search for electronic damage away from the top. A damaged or disconnected ambient temperature sensor (located in the front of the car) will prevent the top from working because the top is no longer capable of monitoring this information. Because the windows are connected to the convertible top electronically, if the doors and door windows are disconnected, they may stop the top from moving. Sometimes a power loss or even low power can cause the top to work improperly.
STEP 2: Know your hydraulics
A hydraulic or an electric motor drive system works in conjunction with the sensors and vehicle computer to drive the top up and down - sometimes in multiple stages. With a multiple stage system, there are several cylinders, lines and motors to operate each step of the top's movement (see Fig. 2). Some vehicles can have as many as 16 to 32 hydraulic lines, and they all use one pump/motor to drive the cylinders.Some auto manufactures require a special fluid when refilling or servicing the hydraulic system (such as BMW and Mercedes-Benz). Adding other types of fluid could damage the system.
STEP 3: Examine the trunk
If a vehicle has experienced a rear end collision, make sure the trunk is properly aligned during the repair and all the sensors and switches are reconnected and installed properly. Trunk damage is a common source of convertible problems because the trunk compartment is used often when the top is raised or lowered.
Also check how storage space is used in the trunk. If the top stores in the trunk, there's a limited amount of space where items can be stored without posing a threat to the top when it is completely retracted (see Fig. 3). Many new BMWs and Chryslers have dividers or panels that, if moved or removed, will make the top nonfunctional. Most of the time, the owner's manual contains information about these items and where to position them to continue the operation of the top.STEP 4: Examine essential features on the top
Look closely at common features such as headliners and insulator pads for damage (see Fig. 4). These are areas to be examined especially when the top is damaged because of vandalism or storm damage and when the top is removed for body repairs.STEP 5: Examine the top material and construction
Convertible tops are constructed to be an outside skin. As such, they may incorporate several panels sealed together that aren't meant to be replaced as separate pieces. The top must be repaired and replaced as a unit.
Convertible tops come in many different colors and types of materials, so it can be difficult to identify the material used to make the top. Some vinyls are made to look like cloth and even have names like sail cloth. In most cases, different layers of materials can be replaced individually and should be replaced on a case by case basis.
Some auto manufactures have started making the top and rear window one piece. The 2008 Ford Mustang, for example, must be replaced as one unit (see Fig. 5). When the windows on these pieces are broken, the entire part must be replaced.Oftentimes, there's a strip of material on the bottom of the top that comes with the window assembly. This strip needs to match the top color and fabric type. Replacement of a convertible top can take between six and 15 hours depending on the type of vehicle and how much of the top needs to be replaced.
STEP 6: Note the differences between OEM, aftermarket tops
An aftermarket top or window may not always include all the special fasteners and retainers the factory tops have, and, therefore, parts must be transferred. This requires more technical skill, but there's usually a huge cost savings, and aftermarket tops often have a better warranty. There are still some cases in which the factory part is recommended as the replacement, such as the rear plastic window in a factory BMW top.
The entire aftermarket industry hasn't quite perfected the fit you'll get from the factory. For the most part, many aftermarket parts fit as well as the factory and have the same quality materials and construction that the factory parts provide.
When it comes to replacing a top, aftermarket or OEM, most convertible tops use similar designs but install in different ways. Some require extensive work. A Honda S2000 requires you to remove all the trim behind the rear seats and console to access the bolts. Sometimes it's easier to remove the seats as well.
STEP 7: Avoid damaging the top during the repair
During replacement or repair, there are a number of wires and sensors that can be damaged or moved. These tend to be hidden in the layers of fabric or in flexible conduits and can be overlooked easily. If any of these sensors or wires are moved or damaged, the top won't work until they're repaired or reinstalled in their proper position.
You'll want to finish any repair by testing the operation of the top. If you've done the job properly, you'll end up with a smooth functioning mechanism that fits attractively to the carefully molded-vehicle form. You'll also delight the often-passionate owners of these special vehicles.
