Got actual MB grease.

My understanding is that, after cleaning the rails, the trick is to use as little of that grease as possible. So I applied what I thought was a VERY thin coating. Seemed to operate smoothly...squeaks were gone. But then I noticed it seemed to be "catching" at a couple of points. So I wiped the rails with a paper towel, assuming that an even thinner layer would remain.

Does that sound about right? Can anyone help me quantify how much grease to use?

Thanks.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

And now, again, it appears to be sticking. What am I doing wrong? What do I need to do?

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I don't think having too much grease would cause a problem with the operation of the roof. If your roof has been dry and squeaking, it might have damaged or worn out slides (jaws) which are felt coated rubber/plastic.
Not too big of a job to remove the sunroof and inspect/replace them if you have the service manual. Bolt head locations should be marked with a paint pen before you remove them so you can get the adjustments back to original.

But why would I develop the problem AFTER applying the grease?

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Those rubber sliding jaws would quickly get damaged if the sunroof was dry and squeaking. Some might even be missing as they can get ripped off their mount from the friction.
Not sure why it would start sticking after applying lube.

You just need to clean it well again and regrease. You may have to experiment with the right amount of grease. The only reason not to use too much is that it will attract dirt. Learn how much it needs for proper operation, then clean and regrease annually or more often if necessary.

Any recommendations as to what kind of a solvent to use? When I cleaned it first time around, I didn't use any kind of solvent...maybe that's needed to do a thorough job.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 158k miles
06 E320 CDI "Rutherford", Black on Tan, 177k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 144k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 72k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Are you sure it's catching or do you need to reprogram it. Try holding the button 10-15 seconds after its fully closed...then open it while hold the button 10-15 seconds after it is fully opened.

__________________
1999 CLK 430
W208
113. Engine
105,000 Miles
Raptor 245/40/17

Wipe away the excess with a paper towel, then I'm sure brake cleaner would work well. If you don't have that, a mix of isopropyl alcohol and water would work fine as well.

Can I use WD40 instead of grease? Thanks!

__________________
1996 E320 since 1/16/08, 171K miles as of Feb 2011

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1989 300CE - R.I.P. Dec 29 2007
Other MBs (sold): 1992 300E-24 - 1979 350SLC - 1984 230E - 1990 300CE

Never use WD40 on ANY plastic bushing! It dissolves the plastic and creates a worse problem.

Use the grease or a heavy silicone spray. Light silicone (one which simply puts a "sheen" on the surface) lasts about as long as a fart in a windstorm.

Some of my friends swear by INOX for lubing plastic/nylon/teflon slides but I haven't used it enough to recommend it.