Published in the July 2014 issue of “Die Porsche Kassette”
I’m referring to the convertible top mechanisms in the Carreras and Boxsters.
Because they shared so many parts, at least the first generation Boxster (’97 - ’99) and the first wasserboxer Carrera in ’99 - ’00, you would think that the soft tops share the same mechanism.
You would think wrong.
They’re both operated from the same switch in the dash and (at least in the first generation of cars) you had to engage the emergency brake (now you can
operate with the car in motion),
but in the Boxsters, an electric
motor operates two independent
mechanical transmissions (one on
each side) via cables, much like the
old mechanical speedometer cables.
The clamshell or protective shroud that you see first start to raise before the top goes down is operated via the same motor through a set of rigid, ball-jointed arms.
In the Carreras, an electric motor operates a hydraulic pump which sends oil to two hydraulic pistons (one on each side) which then operates the soft top.
The clamshell in the Carrera is operated by a second electric motor which starts first, before the hydraulic pump starts to operate.
The systems are quite complex because they just don’t put the top up or down, they perform a series of tasks.
In the Boxster:
1.- In the first generation Boxsters the handbrake needed to be engaged and the red light on the dash needed to be lit otherwise no power went to the top’s motor.
2.- Then the top’s latch needs to be manually unlatched, which in turn opens a microswitch which allows the windows to drop a few inches and at the same time sends a signal to the central locking unit (CLU - black box under the driver’s seat) to let it know that the top is unlatched.
3.- Pressing the top’s switch on the dash turns on the top’s dash light. Continuing to press the microswitch through the complete cycle starts to open the clamshell and the top’s frame begins to fold on it’s own. Older car’s with plastic rear windows should have the plastic “helped” by hand in order for it to fold straight down the middle. Newer cars or older cars that have been upgraded have a glass rear window that obviously doesn’t fold but fits inside the top’s frame as it comes to rest over the engine.
As the top is nearing its resting place, the clamshell begins to close over it until the motor stops on it’s own and finally the top’s light on the dash goes off letting the operator know that the cycle is complete and that the button can be released.
This is all done in a matter of only 12 seconds!
For those that are so impatient that they can’t hold the button for that period of time, there is an aftermarket product called the One-Touch that will do it for you with a single touch of the button. It will also make your wallet significantly lighter ;)
In the Carrera:
When the dash button is pressed, the top’s latch automatically drops and unlatches the top’s front edge.
The windows (all four) start to drop all the way down and the clamshell starts to open.
The hydraulic pump pressurizes the system and sends oil to each of the two hydraulic pistons which start to move the top until it reaches its resting place.
The clamshell then closes over the top and rests in its original place.
Because they are complex mechanisms, some of the components can and will fail with time and use and could leave you with a non-functioning top in the open position which is not good, especially here in Florida, where we only have two seasons: the rainy season and the very-rainy season ;)
So, what can fail, and what can you do?
The most common failures we’ve seen are:
In the Carrera, leaking hydraulic pistons. These tend to leak out the oil through its seals, once they become dry and brittle from age and or lack of use.
You can know they are leaking in one of three ways:
1.- The hydraulic pump runs but the top barely moves or doesn’t move at all.
2.- You can see a puddle of hydraulic oil under the corresponding side, just in front of the rear tire.
3.- When the top is down you can actually reach in and feel the pistons. If they are oily, they are leaking.
If you are caught with the top in the Open position and need to close it, while pressing the top’s button, hold the front edge of the convertible top and manually pull up and forward assisting the failed hydraulics. Keep the button pressed until the latch securely closes. Now the top is secured in the closed position but you will need to have the hydraulic piston(s) replaced. Not cheap.
They can also be rebuilt for a fraction of the cost of new ones.
In the Boxster, there are various failure points.
1.- The transmissions have internal nylon sprockets designed to break before causing damage by an improperly operating top.
2.- The transmission cables tend to stretch their outer shrouds and disengage with the transmission thereby rendering the corresponding transmission immobile and warping the top since only one side works.
3.- The convertible’s plastic link ends (black and or red) break causing the top to open/close one side only.
If any of these things happen, there is an emergency procedure to allow you to manually close your convertible top:
Remove the black plastic link covers on the outer edge of the convertible top.
Using a large, flat screwdriver, or pry-bar, pry off the black-tipped link on either side of the top. This allows you to manually lift back the “clamshell”.
Using the same screwdriver or pry-bar, pry off the red-tipped link on either side of the top. This allows you to manually raise the convertible top.
After the convertible top is closed, securely latch it and then close the clamshell by hand.
Because the clamshell is not properly secure maintain a safe maximum speed of less than 60 mph until you can have the top repaired. Not too expensive.
For more information on cabriolet technology, please visit my website: www PedrosGarage.com.
Ⓒ2014 Technolab / PedrosGarage.com