928 Window Regulators

The passenger side window on my 1979 928 fell all the way down.  When this happens, it is due to the plastic regulator roller (wheel) breaking.

 

In the diagram above,
Roller is Item # 3 part number 928 537 918 00
The Roller Bolt is item # 4 part number 928 537 917 00
However, the bolt is not threaded, it is pressed into place and has to be drilled out and pressed back into place.  It is easy to damage the roller during this process.

While repairing the window regulator, you may as well replace the upper and lower slides that hold the window in place on the support rod.

Left Lower Slide is item #12 part number 928 537 259 02
Right side Lower Slide #(12) is part number 928 537 260 02
 
Left Upper Slide is item #13 Part number 928 537 289 02
Right Upper Slide is item #(13) part number 928 537 290 02



I had further complications; there are two bolts that fit though the upper slide that connects to the base of the window.  The associated nuts are held into place on the window base towards the outside of the car by a plastic cap.  The two caps broke so the bolts would not come loose.  My mechanic had to cut apart the upper slide to gain access to remove the bolts – it wasn’t easy.  Apparently this is common enough that by the 928 GTS years, the parts catalog lists replacement parts.  In the diagram above,The fastening plug is item #8, part number 928 537 281 04The threaded piece (bolt) is item #9 part number 928 537 277 02Both of these items were not stocked by Porsche USA and had to be ordered from Porsche Germany.  You’ll need a set of two for each window side.

I've created a more in-depth document with photos about the window regulator repair.  It isn't a step-by-step how to do document. However, with photos many more of the difficult and possibly confusing issues are highlighted.  To get a copy, you can email me at 928ocmembership@earthlink.net and I'll send it to you.