Erratic W126 sunroof

I see lots of different sunroof woes here. Here's another. Sunroof most often opens slow and/or choppy. Isn't popping up without a helping hand, either. But always closes smooth and steady. Weird. Have also noticed if car is moving forward, roof almost always opens perfectly. If braking, sunroof barely moves and doesn't always open fully. Have lubed with white lithium grease and/or silicone sprays (and I always clean tracks before lubricating). Any advice?


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Rob
1991 300SEL

[Q]

The difference you are seeing at idle and while moving is probably due to the voltage difference. When a car is idling, the alternator doesn't produce the same output as it does when above 1500 RPM. Since you say it has a choppy movement, your cable is probably bad. When it is moving slow, the cable is causing drag and with the lower voltage from the charging system, the motor doesn't have the power to move it. This is just a guess though.

[420SEL]

I would say the problem is most probabby the cable. I had the same problem( though it was not affected by my driving/stopping.) Althought the coments about the motor not getting enough juice are worth looking into.

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Jason Priest
1986 420SEL