The convertible top on the Porsche Carrera is hydraulically actuated. This means that rather than using the traditional approach of cable and pullies, the car uses a set of pressurized cylinders to both open and close the top. Over time, the system can leak or fail, causing your convertible top to get stuck in either the up or down position. In this article I will explain the basics of the system.
The basic operation of the system boils down to the use of two hydraulic actuators, mounted inside each rear interior panel. Each actuator is fed by the main system pump. If the system is low on fluid, it can operate loudly and cause the top to stop working. If you are having problems with your top, there is a chance you could just be low on hydraulic fluid. Sometimes simply adding fluid to the system can get it working again. Additionally, the fluid in the reservoir can go bad, especially if there are leaks or contaminants, causing the system to work harder.
Begin by moving the convertible top to the service position. This is where the front edge of the convertible top is about 12-15 inches from the top edge of the windshield. This is so you can keep the body flap open and also gain access to the pump. Once the top is in the service position, look under the rear window flap to find the guide cable connections. These are attached to the car with two ball joints (picture 1). The idea here is to keep the rear window flap down when the top is opening or closing. Pop both cables off the ball joints and fold the rear window flap up over the top.
Directly below, you’ll see a carpeted area held in place with four plastic rivets. Pry the rivets out with a small screwdriver and carefully work the carpeting over the two large plastic blocks on either end. Once the carpet is clear of the blocks, pull the carpeting up and out of the car. You’ll see the hydraulic pump for the system underneath. You’ll also have access to the rear body flap motor as well as the DME computer and the relays. Locate the two hydraulic lines going out from the pump to the actuators. In between the lines on the pump, you’ll see a hex plug. This is where you fill the system. Directly under the pump is the fluid reservoir. Shine a flashlight behind it to see the fluid level inside. The fill level line is right below the fill port plug. If you have determined that the fluid level is low, remove the hex plug and use a small syringe along with some plastic tubing to fill up the reservoir.
Another part of the system that can fail is the front latch mechanism on the center front of the convertible top. This motor assembly extends a hook out that latches the top against the windshield frame. If the motor inside fails, you can still manually open or close the latch. To access the latch assembly, pry the plastic cover off the latch mechanism from the front. Underneath you’ll see the manual over-ride actuator and the mounting points for the latch mechanism. To open or close the latch, insert the 6mm hex key into the over-ride actuator and turn it counter-clockwise to close the latch (this is the same tool used to emergency open/close the entire top, located behind the rear seat panel) Turning it clockwise opens the latch. If you need to replace the entire latch mechanism, remove the four Torx bolts holding it to the convertible top and then remove the electrical connectors going to it. Installing the new latch mechanism is the reverse of removal.
If the convertible top cannot be opened using the switch, you can open it manually. This procedure is intended to be used only as a last resort as you can lose the reference points for the system to operate correctly, requiring the use of a Porsche factory computer to reset them. Begin by removing the rear panel behind the seats. This is held in place by two Philips head screws.
Once the panel is removed, you’ll see the two access points for opening and closing the top as well as the tool stored on the bulkhead. For instructional purposes, we will assume the top needs to be closed. Begin by prying the circular covers off the roll bar bulkhead and insert the tool into the hex slot below. Now rotate the tool until both side flaps have been opened.
Now move back to inside the car. Locate the port on the right which turns the convertible body flap motor. Insert the tool and rotate it counter clockwise until the body flap is fully extended. Now insert the tool into the left side port and turn it counterclockwise one turn. This port is a pressure relief screw for the convertible top. Opening it allows you to grab the top and manually move it yourself. Grab the top in the middle and pull it up and over the car. Now use the manual over ride on the front latch mechanism to lock the top down.
1:: Once the top has been extended into service position and the rear body flap is open, access the hydraulic pump by first prying the rear window guide cable ends off the ball joints on either side of the car (blue arrow)
5:: Shown here is the hydraulic pump that powers the whole mechanism. Over time, it may be necessary to add fluid to the reservoir below the pump (yellow arrow). To add fluid, remove the fill port plug (green arrow). Add hydraulic fluid until the level in the reservoir reaches the high mark which is located below the fill plug. Use a syringe with a long tube to both withdraw the old fluid from the reservoir and also add new fluid. Here you can also see the DME (blue arrow) and the DME relays (red arrow).
6:: Shown here is one of the two hydraulic actuators used to both raise and lower the top (green arrow). They are located behind each rear side panel. The actuators are mechanically linked to the convertible top frame, so that when the actuators expand, the top raises. Here you can see parts of the convertible frame (blue arrows).
7:: The front latch at the windshield can also fail over time. However, you can also manually override the electric motor. Pull the cover off the front latch mechanism by pulling down on the plastic cover at the front (insert upper left, green arrow). Shown here is the front latch assembly with the cover removed. In thisPicture, you can see the manual override port (green arrow). Turning the 6mm screw inside counter-clockwise closes the latch, turning it clockwise opens the latch.
9:: Once the front latch assembly has been removed from the top, squeeze the black tabs on both of the electrical connectors (green arrows) to disconnect them. Now you are ready to install the new latch assembly.
10:: Access the manual over-ride for the top requires removal of the panel directly behind the upper rear seats. Fold the rear seats down and remove the two Phillips head screws holding it in place. Now pull the panel out of the car.
11:: Once the rear body flap has been removed, you’ll have access to manually lower or raise the top. Shown here is the bleed valve used to actuate the convertible top frame (green arrow), the manual motor override for the rear body flap (yellow arrow) and the actuation tool stored on the bulkhead (purple arrow).
12:: To manually open or close the top, you’ll first need to use the tool to open the side flaps on the car (green arrow). Rotate the tool counter-clockwise until the side flap is fully open (yellow arrow).
13:: You’ll next need to open the body flap on the rear of the car. Insert the tool into the port on the right (green arrow) and turn the tool counter-clockwise until the body flap is fully extended. The left port on the car is simply a pressure relief valve for the convertible top pump (blue arrow). You’ll need to open this port to allow the system pressure to bleed off. Turn the valve counter-clockwise one revolution. If the top is already closed, simply push it back until it folds back into the car by itself. If the top is already open, grab the top in the middle and pull it up and over until it is just nearly closed. Now use the front latch assembly over-ride port to close the top fully. Once closed, re-tighten the valve. Keep in mind that using this method of opening and closing the top may require you to reset the reference points in the system using a factory Porsche computer, such as a PS2.
Comments: Hi: my name is wally I have proplem in 1999 carrera lid not working Top motor is fine ??
December 4, 2013
Comments: Hi Nick
Your info is very useful, today I follow your steps to try to fix the roof, I find the design of the motor and oil bottle is difference from your photos, it is horizontal see attach photos, we find the oil is very low, so we went to Porsche shop to buy the oil, unfortunately they don't have stock, may I know any compatible oil in the market, what is the brand name and model number?
December 3, 2013
Followup from the Pelican Staff: Give our parts specialists a call at 1-888-280-7799 and they can help. - Nick at Pelican Parts
Comments: Hi Nick
Thanks for your reply, when I pull up the button, the roof open little bit and no power to continue, I need use hand to push it, the roof can open 100%, when I press the button down, the roof has no power to close, I need use my hand to help to close, the roof can close 100%, the hook can lock the roof. when I pull or push the button the roof make some noise very little, you say the micro switch faulty, where it the switch and how much?
I feel the roof is not enough power to open and close, do you know which part has problem.
November 28, 2013
Followup from the Pelican Staff: If the motor is attempting to work but lacks power or force. The motor could be faulty, or there could be a part jamming the motor. I would check that the motor is getting power when you attempt to open it. If it is getting good power and the motor is not working it could be faulty.- Nick at Pelican Parts
Comments: Hi Nick
Thanks for your info above, my car is 911 977 year 2007, last week the top can only open very little, is around 10", I still can close it.
I read your tips very carefully but from figure 5 to figure 6 I don't understand how I can see the hydraulic actuators, do I need to remove something?
I did not go to repair it yet.
November 26, 2013
Followup from the Pelican Staff: There could be a faulty microswitch. Does the top make any noise when you try to open it? - Nick at Pelican Parts
Comments: Jacolas Take the top into service mode and you will see where the clam shell latches into the H style bracket under the clam shell. You also see the hook sticking up which goes into that final pull down on the clam shell closing it completely. Put a good dab of O ring grease or similar onto each part ie:- The hook and the H bracket. Try it again. I had the same problem and this action solved it. The hook was not going completely into the bracket because both were very dry and binding on each other. Good luck.
October 10, 2013
Followup from the Pelican Staff: Thanks for the input on this one. We appreciate the help. - Nick at Pelican Parts
Comments: Thanks Nick, different pump but thanks for all your help. Roof is working perfect now, £70.00 and 3 weeks later. I filled the resevoir via plug at end then operated the hood several times by hand pausing to bleed the pipes inbetween. Took about 1 litre. just got lucky I guess. Cheers again
October 8, 2013
Followup from the Pelican Staff: Ah, thanks. You must have the metal reservoir?
Would you mind sharing some info about the pump type you have.
- Nick at Pelican Parts
Comments: Thanks for you earlier post. MICE CHEWED HOSE . I have removed the hoses and had them repaired . I now need to top up the pump and hose etc. I have a different one to the one in your photo.It sits horizontal and has a white resevoir on the end. There is a brass plug in this and 3 other plugs in the motor section of the unit. any advice on how to refill the system appreciated. Thanks Jon Liverpool uk.PS The mice realy LIKED peanut butter
October 4, 2013
Followup from the Pelican Staff: Remove the interior trim panels to expose the pump motor and lines. The pump motor has a clear reservoir on the bottom. There is a a hex head plug in the fill hole right above the reservoir, between two hydraulic line fittings. - Nick at Pelican Parts
Comments: hello, ive just bought carrera 4s 1999 model, i put roof down and when i tried putting it up it wouldnt work, so idone emergency operation,now roof wont work, is there some sort of override system ?? in the manual it says take to porsche dealer, is there any way i can fix problem my self thanks.
September 27, 2013
Followup from the Pelican Staff: Can you hear the top motor run? If not, I would start by checking the fuses. - Nick at Pelican Parts
Comments: Hi,for the first time in many years I put the hardtop on my Porsche 911 Carrera 4s 2004. 3 weeks later I took it off and tred to operate the soft top . It went half way up and stopped. after further investigation I suspected mice in the lining few holes couple of seeds on the floor. I sort of traced their route and eventually found a nest behind the back seat in amongst all the hydraulic stuff. So far I have discovered they have chewed through one of the hydraulic hoses, which explains why the roof went half way up.I have read your article on filling up the fluid but could do with some advice on reparing or replacing the hose. I couldnt believe it. cheers JOLLY Liverpool UK
September 12, 2013
Followup from the Pelican Staff: Here is what I remember about replacing the lines:
1. Place top in top-up/locked position and activate the top-down operation just enough to unlock the front top latch and retract the rear deck.
2. Remove the key so that the top cannot be accidentally activated during the procedure.
3. Reach under the deck, remove the rear top anchoring cable ends by levering them off with a prying tool. There is one on each side.
3. Lift up the back edge of the top and push it forward. The top should stay in this position without support. Note: From 2002, cars with rear glass window, the back edge of the top will need to be supported to stay open.
4. Remove the rear deck carpeting
5. Remove the retaining clips from the hydraulic cylinder drive pin and frame pin. Remove the left and right drive arm. Remove the drive arm off the pins.
6. Gently pull up on the hydraulic lines to remove them from the mounting brackets. be careful not to bend the lines.
7. Unbolt the banjo bolts for the lines and remove them. Note the positon of the sealing washers and any electrical connectors.
- Nick at Pelican Parts
Comments: There is an oil leak just ahead of the rear passenger side wheel on my 996.
And of course, the soft top stopped working. Can you tell by my quick description what seems to be the problem? Do I have to replace any part?
Should I be able to fix it my self?
Tks for your help.
August 25, 2013
Followup from the Pelican Staff: Without knowing where the leak is coming form, I cannot tell you what to fix. If you pinpoit the leak and describe the area I could be more help. Try jcking the vehicle and looking for the source of the leak. Look for dripping or a clean oil soaked area. - Nick at Pelican Parts
Comments: Reference above ie clouding flap , I had the sme problem. I solved it by taking off the potentiometer on top offlap motor drive and adjusting. There is a resistance measurement if between 6.4 and 7.2 ohms fir setting but the cruder way is to lift off potentiometer and rotate by one segment at a time. Trial and error system but I got there and mine works great now .
Hope this helps. Jack Brown, UK.
August 7, 2013
Followup from the Pelican Staff: Thanks for the additional information. We appreciate it. - Nick at Pelican Parts
Comments: Yes, we had the same problem... After replacing the right rear window regulator we were "excersizing" the top to make sure all was OK and on the third time when the right side cable the pushes and pulls the lid down.. broke.. $700 later and a trip to the shop that has a PST2 to recalibrate got the top operating...Customer, of course, wanted to know "Who broke it"... Had to supply the normal response... "It broke itself" not very satisfying to the customer but still the truth... now the car's back again for slow operation and stopping... Probably low on fluid.. a leak somewhere...
August 4, 2013
Followup from the Pelican Staff: Thanks for the Info. We appreciate it. - Nick at Pelican Parts
Comments: Hi Nick. Two weeks later and in spite of your great guide to the workings, I am still in trouble with my convertible hood operation, 911, 996 model. 1999 year.
We can now operate all on the hood other than the final stage of closing the crescent hood cover. The motor appears to be running but not closing the lid. Is it a worm drive for this operation and have you heard of any problems like this. As always I would be gratefull for any help.
June 14, 2013
Followup from the Pelican Staff: Not specifically what you are describing. I would guess a switch is not in the correct position when closing. Might be time for some proefessional help.- Nick at Pelican Parts
Comments: This has to be the best, the most professional and the most helpful I believe, on the Internet. I have not applied as yet but my thanks to the author and company in advance. Any business to be done will definitely go they way.
May 28, 2013
Followup from the Pelican Staff: Thanks for the kudos - Nick at Pelican Parts
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