Technical Service Bulletin Updating Parallel arm window regulators 

Subject: Service Installation Electric Cross Arm Window Controls   Models: 911/911 Turbo/911 Targa 1980

Bulletin Number: 80 – 04

General Information

Electric cross arm window controls are installed in all cars as of the 1980 model year. These new window controls guarantee smoother door window operation and in future will replace all parallel arm window controls for Types 911 and 911 Turbo.

Later the parts Catalog will be changed to include the mechanical cross arm window controls, which replace the mechanical parallel arm window controls after depletion of stocks and can be installed in all doors.

Service installation of these new cross arm window controls will require exchange of the lift channels on the door windows or use of new door windows.


  1. Remove inside door trim panel. Disconnect window control and mirror switch.
  1. Pull off door wind water shields.
  2. Loosen and remove door window frame.
  3. Disconnect parallel arm window control, detach door window at guide and remove.
  4. Remove window control and electric motor.
  5. Remove height adjusting screw on Targa doors.
  6. Loosen old lift channels from window by lightly tapping and then remove.


  1. Position new lift channel with cleaned (wax free) rubber insert on window glass and press on tight. The lift channel for Coupe door windows must be positioned 8 mm behind the front edge of the glass.

The plastic part of Targa window lift channels will have to be coated with rain molding cement, e.g. National Special Cement 670, at the groove.

Then install window glass so that it rests firmly in guide groove and channel.

  • Mount electric motor on new cross arm window control (arrows). Guide wire harness between bolts so they will not interfere with moving parts. Set window control at center position for installation in door.
  • Find location for holes on inside door panel with a compass according to given dimensions and drill two 7.0 mm (9/32 in.) dia. holes.


If door window sags at rear when operated, the rear mounting hole (see broken line) must be extended upward.


A slot must be made according to given dimensions in door inside panel of Targa models. The stop bracket for height control will be accessible through this opening.

  • Check window guides for wear and replace if velvet is partially worn. Glue at top when inserting in door window frame.
  • Insert window control and bolt base plate. Connect wire harness with switch.
  • Insert window glass and guide plastic rollers of window control into window lift channel. Mount short guide rail on inside door panel with M 6 x 10 bolts and washers. Lubricate moving parts with a multi-purpose grease.
  • Install and secure door window frame.
  • Check door window for easy movement. Close door and check periphery of glass and/or window frame for neat fit at door weatherstrip, correcting window frame adjustment if necessary.
  • Install door window water shields and inside door trim panel. Check operation of window control and mirror switch.

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