Seeking help: Sunroof sticking in tilted-up position.

[Super77]

Building on this thread, which describes a similar issue but no clear resolution.

My sunroof has worked perfectly up to today. I exercise it at least once a month: open/close/tilt, and blow debris out of the nooks and crannies, clear the drains annually. Never lubed it, though. But no issues.

Today I noticed the motor was really straining to get it open and closed, and ultimately, I could not get it to tilt back down and closed. I removed the glass panel. When I hit the tilt-down button, the motor makes a straining noise. The passenger side tilting mechanism moves a little, the driver size does not move at all. Pressing down on the mechanism does not help.

There is a visible component that slides fore-aft and tilts the back edge of the sunroof up with a jointed mechanism. This piece is in a rail, and I noticed that on the driver side it was frozen in place on the rail. I pushed it backwards with a screwdriver while pressing the down-tilt button, and motor labored but got the mechanism closed. It feels like that sliding part, just on the driver side, needs to be lubed. I sprayed a little lithium grease around it, but it got stuck again and needed another screwdriver assist. The sunroof is closed now, but the problem isn't resolved. This is the mechanism (not my vehicle):

For tilt, part of it slides backward, which pushes the back edge of the glass up as shown by the green arrows.

Question: how do you disassemble and lube the sliding/folding/lifting mechanism for tilt? I don't think this is a drop-the-headliner situation because the motor and gear cable seem to work - I think it's just a bound up tilt mechanism that is fully exposed with the glass removed. Could not find a how-to with pics here.

 

[TahoeZ]

Each of those moving parts needs to be well-lubricated. I lube everything up at least once a year. You might be able to soak it in PB or Kroil to get the debris or rust to break up.

Everything can be accessed by removing the glass. Four nuts under the black plastic trim pieces accessible from below and the glass lifts out.

 

[Malleus]

^agree, but I wouldn't use any oil–based lubricant. The dirt will cling to it and you'll get more drama. White lithium is what was used, and that's the best stuff to continue to lubricate with, IME, but you really have to get it clean first. My second choice would be Teflon spray. I use it exclusively on lock mechanisms.

If you can get everything apart, a good soak and wash with dishsoap will remove the trash that's accumulated in there. It will not remove any rust in there, though.

I have had good luck, once the cassette is out cleaning with SuperZilla. This stuff doesn't seem to attract debris, and does seem to eat minor rust away. FWIW, it's the only thing I've found that will dissolve brake fluid–induced rust on brake fittings; so take that as an example.

 

[Super77]

Welp, I watched the Car Care Nut’s 43 minute video of a full teardown and replacement of a 100-series sunroof, and now that I understand better how the mechanism works I’m wondering whether I have a bound-up drive cable on the driver side. At about 14:20 in the video he discusses the part I’m having a problem with.

That sliding block I mentioned is connected to the drive cable, so it’s hard to tell whether the resistance is coming from the block itself or the cable inside its tube. Having to replace a cable would be unfortunate so I want to do some headliner-in-place troubleshooting.

Can anyone suggest how to to access and inspect enough of the cable to determine cause, short of dropping the headliner? Anyone successfully lubed their cable like this? My sunroof is closed right now so not an emergency, but I’d like to understand what’s going on.