993 - Targa Roof Operation Outline - Pcarworkshop
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993 - Targa Roof Operation Outline - pcarworkshop http://www.pcarworkshop.com/index.php/993_-_Targa_Roof_Operation... 993 - Targa Roof Operation Outline From pcarworkshop Contents 1 Introduction 2 The Main Tracks 3 The Drive Cables 4 The Drive Motors & Cables 5 Two Types of Rear Gate Guides 6 The Cables and the “letting go” Mechanism 7 The Visor and Front of the Glass Roof 8 The Sunblind 9 Basic Roof Height Adjustment 10 Setting the Roof Timing Stop Points Introduction The 993 Targa top is one of the most unnecessarily complicated systems I have ever seen. A company called Webasto manufactures it for Porsche. They make OEM sunroof mechanisms for various auto manufacturers. It is a design that seems to have been created by engineer geeks with access to a shop full of machines and machinists to create whatever they come up with that day. This mentality is further noticeable in how everything seems to have been designed with no forethought for repair. One begins to believe that this may have been done to require service to be done by factory personnel only. When I was looking for my Targa I had heard about there being problems with the roofs. My mechanic said, "buy a coupe or cabriolet, the tops break and sometimes we can’t even fix 'em." But after living most of my adult life with a Targa in one form or another (a 1973 914, a 1968 911L and a 1984 Carrera) I decided to get one anyway. I found one in the color combo that I wanted and the owner said he just spent 1200 dollars at the dealer repairing the top and replacing parts. So I figured it was probably one of the safest bets I could find in a Targa purchase. After driving it about 2000 miles there was a loud clonk and the top jammed and started clicking–a sort of ratcheting noise–when I pressed the button. I messed with it, lubed it up and it would open all the way but at the last push to bring the rear of the glass up, it would jam and make the ratchet noise. Because the top wouldn’t close all the way, the wind deflector wouldn’t come down. I removed the drive motors in the back under the rear deck and discovered that the cables were stripped a bit and figured that was the problem. I ordered what is called a “repair kit” which is essentially the two glass top drive cables and a bunch of little plastic bits. The list price on the top repair kit, which is the only way to buy the drive cables, is about $1100. Sunset Porsche [1] (http://www.sunsetimports.com/) got it to me for just over $800 In buying the car, the previous owner said the dealer had done a repair, which gave me confidence. I found out later that virtually no one, at least who I talked to–other Targa owners, various dealer parts guys, independent mechanics and dealer service people–has a concept of how this mechanism works. Compound this issue with the fact 1 of 16 7/17/2012 5:03 PM 993 - Targa Roof Operation Outline - pcarworkshop http://www.pcarworkshop.com/index.php/993_-_Targa_Roof_Operation... that Webasto has updated parts over the years and some newer ones don’t work with other older ones. No one I spoke with knew about some of the updates. I was originally going to do a step by step DIY on how to remove and replace the mechanism for operating the Glass Roof and Sunblind, but it is a lot, as you will see, so I decided to do this overview instead. Procedures are covered in the service notes which are available here on MikeJ's Pcarworkshop.com In the TSBs, Parts Guides section for the 993. Here are direct links: Targa Service Technical Notes Part 1 and Targa Service Technical Notes Part 2 Note: Mikej asks that you limit your downloads. By combining the information herein with the Targa service guides you can pretty much figure it out. If you have any problems, or other questions, PM me on Rennlist, username: "Amfab" One problem with the Service Guide is that the glass roof drive mechanism is not designed to be replaced with the top on the car, and so the Service Guide describes the procedure with the top off the car. And by top I mean the whole top. The Targa is based on the cabriolet body with some modifications here and there. The top is a single unit that comes from Webasto and is bolted and bonded with adhesive to the body. Mike, who created this site is the only one I know who has attempted (successfully) a complete top replacement, and I will leave explanations of that to him. The glass roof drive mechanism is designed to be replaced with the top off the car. However it can be done with the top on the car, but it is far from easy. If you are going to attempt this, or if anyone has specific questions, again, you can contact me through Rennlist, username: Amfab . I encourage anyone with a Porsche to become a member, the assistance and information you will receive there is invaluable. In this document I left out a full explanation of how the Wind Deflector works as it is self evident to a Targa owner–once the function of the cables and Gate Guides is understood–how the Wind Deflector pivots up and down. I also want to thank Mike and Robin for their contributions to the 993 community, and with a special note to Mike who was the only person on the planet whom I felt fully understood, and empathized with my frustrations with the top as I undertook this project. -Andrew MacKenzie The Main Tracks Running inside the two sides of the roof, above the side windows, are two large extruded aluminum channels that are bent to follow the inside of the roofline. On this page are two pictures. One, a drawing I did of a section of the track, and an actual photo of the track removed from my car In these two pictures the right, or passenger’s side track is shown. 2 of 16 7/17/2012 5:03 PM 993 - Targa Roof Operation Outline - pcarworkshop http://www.pcarworkshop.com/index.php/993_-_Targa_Roof_Operation... The large upright part on the outer side (left in the pictures) has eight holes where the hex bolts are. These bolt the track into the frame of the top. The two round tubular shaped portions of the track carry the drive cables. The cables are actually long springs that act as flexible rack gears that gets driven by motors under the rear deck. The Drive Cables The top cable in the above picture is a healthy new cable. It essentially is along spring with a pipe cleaner running down the middle. The little hairs help to keep the track clean. You do not want to lube these cables. It will not help them to move more freely and will only gum them up while causing potential slippage against the drive gears of the motors. The second cable down is one that has been stripped against the drive gear of a motor. The third one down shows a mild kink. This kink is enough to cause binding, which can lead to stripping. Any work done on the mechanism that involves removing of the tracks or cables requires a lot of care to avoid any kinking. The cables are the same type for the Sunblind mechanism–this is the cable that runs in the inside tube of track–and for the top mechanism, which runs in the inside tube of the track. The Drive Motors & Cables The three drive motors sit under the upholstered rear deck. Two of the motors drive both sides of the top and one motor drives both sides of the Sunblind. It is the gear at the head of the motor that drives the cables. Here is a photo of the three motors; they mount on a metal plate on the back deck. The motors have a red plastic cap (seen on the top motor in the picture below) that can be removed to allow the top or blind to be moved manually with allen wrenches. These caps interlock the motor to the drive mechanism. If these red caps are damaged to the point of being unusable, the motors will not be able to engage the drive gears. Porsche only sells the motor with the caps as a complete unit (list price is in the $600 range). User "Targagr" from Rennlist discovered that Audi sells these same plastic caps separately (part number: 895 877 899) for a couple bucks each. 'Italic text' The photo shows the single Sunblind motor mounted and the two glass roof drive motors removed from their mounts. Visible are the three threaded mounting holes for each motor where the bolts go to hold the motors that are removed. Care must be taken not to over torque these as they strip very easily. The mounting plate is soft steel and it isn’t thick enough to have sufficient threads. I stripped two of them, even being very careful. The motors’ gear fits in the gaps between the two lower cable tubes. In the picture below one cable is removed. The gears on the end of the motors drive the cables directly. The cable is held against the gear by the metal channels on the motor head right next to the gear.