my write up.... sorry no pics - HINT - buy extra gears, they are cheap and you are going to strip one, I can speak from experience!
Here's my rather lengthy post on sunroof adjustment after I replaced 2 sets in 2 cars (and stripped a brand new set of gears!)
BTW - buy a spare or 2 if you are doing this the first time - skip eBay, just buy the gears from Paragon - best deal around at $7.05 each
Well here’s a low down and maybe this will save some headaches (this was written for 944's but the mechanism should be the same for 968)
1. From what I can tell, after looking at the “old” style mechanism and then the “post 86” style, both units seem to have similar problems.
2. All the articles talk about limit switch adjustment, cams, levers, etc. possibly going out of adjustment with time, but the real culprit appears to be the SLIP CLUTCH that is common to both systems.
3. From what I can deduce, there’s an easy way to narrow down the source of the problem.
a. Carefully depress the switch to take the roof OFF the car (key position #1 on post 86 cars).
b. Get into the back seat (parking brake on and out of gear!) Then switch the ignition to position #2 to operate the TILT mechanism while DEPRESSING THE CENTER SWITCH ABOVE THE MIRROR – where the “tab” on the roof panel usually presses on a hidden switch. If the gears are not badly stripped, you can either see the arms moving in / out or at least hear the drive mechanism run to the limits and stop.
c. If the motor just keeps running, then the limit switch (one is for roof UP) the other for roof (locked closed) is out of adjustment.
4. If the roof arm (one or both) operate normally, then it’s probably the SLIP CLUTCH is out of adjustment. The slip clutch really only comes into play when you depress the console switch to REMOVE the roof panel. What happens is that the arms travel back farther than in “tilt” mode until they are flush with the little gearbox.
a. The operating logic is that the arms move back into the gearbox and the Slip Clutch is supposed to “limit” any further movement! There is no “limit switch” to stop the arms – the system depends on the slip clutch, and if that fails then the PLASTIC GEARS strip!
In any event, you will have to get into the headliner to change those PLASTIC GEARS. Instead of removing the headliner however, all you really need to do is to remove the PANEL that covers the drive mechanism. Then instead of taking off the trim etc (it’s glued on, and I hate having to re-stretch and try to get it all to fit without wrinkling) – just use scissors and cut an “L” to expose the gearbox and tuck the material back underneath. When you replace the rigid panel, it all gets hidden anyway!
In the “tilt” mode, the aluminum raising arms on my car showed about 3 gear teeth clear of the gearbox. That way it engaged the roof panel receptacle almost perfectly to bring the panel flush with the roof.
The trickiest part is adjusting the SLIP CLUTCH torque – the manual calls for 6Nm +/- ½ but that is so low you might as well guess at a setting that just raises and lowers the roof to lock it down plus a smidgen more. Anything more and the plastic gears are going to take a beating when you retract the arms for “panel removal” mode.
BTW, the 13mm locking nut to adjust the torque setting on the SLIP CLUTCH is very thin – too slim for normal wrenches. Bike tools should fit. In any event, back it off a bit to save those gears!
If your roof works fine in Switch Pos #2 (goes up and down, and locks) but does NOTHING in Switch Pos #1, then it's probably the microswitch just above the rear view mirror. If you look at the front of the sunroof from inside the car, both ends have a "over center catch", while the "middle" only has a "tab". That tab depresses a microswitch that indicates whether the roof panel is "on or off" the car. If there is no pressure on the pad (switch out of adjustment for example), the logic is that the roof panel is removed and the sunroof drive mechanism will not get any power. This is to prevent you from extending the lifting arms when there is no panel present.
Try pushing "UP" a bit on that center tab while depressing the sunroof switch (try both ways) while the switch is in Pos #1. If the arms release the roof panel, it's an easy adjustment to re-engage that switch.
One way to test this - but you better be prepared to strip gears - is to take the roof panel off manually to eliminate any load on the mechanism. Then - EXTEND THE 2 LIFTING ARMS MANUALLY ABOUT 1/2 WAY OUT - next, while you DEPRESS the CENTER SWITCH above the rear view mirror (to trick the system logic - as if the panel was actually still installed) - use the rocker switch to see if you can move the ARMS ONLY.
If they move, it means the slip clutch is out of adjustment and cannot take any load. It's doing what it is supposed to do - protect the electric motor and drive mechanism. The Plastic Sunroof Gears in the transfer box are there as backup protection, and I believe are MADE to strip in the event the clutch is out of adjustment to the other extreme.
To adjust the torque setting on the slip clutch, use a thin 13mm bike wrench to hold the inner nut while using a socket or open end wrench to unlock the outermost 13mm nut. Then adjust the innermost 13mm nut to 6 nm or less torque - best is just enough to get the roof to move up and down and lock. The torque setting on the slip clutch does not have to "lock" the roof panel closed. It only has to move the lifting arms to the right position (about 3 gear teeth showing out of the transfer box) to "lock" the panel in position by having the end of the lifting arm lodged into the "bent knee" receptacle in the roof panel.
The limit switches when set correctly actually set the limits of the tilt and lock movement of the roof panel WHEN IT IS INSTALLED.
The Slip Clutch is really there to only limit the RETRACTION into the headliner for REMOVING THE ROOF PANEL. It's a nutty design (but then the whole thing is kinda overkill to raise and lower the panel for tilt only).
