Door Windows - Slider Boss Mounting Plate and Guide Channels

[Paul GC]

I am new to the Elan M100 world but have been on a classic car "journey" now for about 15 years majoring with MGs. I have an early M100 with "opera glass" headlights, low mileage and in great condition. I noticed that the drivers window glass lowered ok but was slow to raise and on a recent trip to Prescott Hill Climb, the passenger door window failed at the half down position with a "snapping" noise (it was the regulator). To cut a long story short, I now have both doors glass mechanism completely dismantled. I have had the passenger door lift mechanism repaired and rebuilt the door windows with new bushes, bosses, slider bosses etc. I have also bonded new slider boss mounting plates on the rear edge of both windows. I have struggled with putting the door glass back into the doors for days but following the various threads here on LEC, managed to get the passenger door glass back into the door only for the upper attachment of the rear guide channel to shear off!!! Whilst I am waiting to source a replacement rear guide channel I have a few assorted questions, the experts here on LEC might be able to help me with.

In the Lotus Service Notes, section BK page 10, the rear slider boss mounting plates shows that both slider bosses are 12 mm. On my car, the original bonded plates on both door windows was a narrow metal area with plastic slider bosses permanently attached but the lower one was 12 mm and the upper one 8 mm. The new slider boss mounting plates (A100B1233/34F) are a larger area (which presumably gives a stronger bond to the glass) and have built in, metal slider bosses which are, again, 12mm at the bottom and 8mm at the top.

My questions are -
why are they not both 12 mm as the Service Notes show?
As the centres of the slider bosses are closer together at the rear edge compared to the front edge, surely this height difference is going to cause more drag in the guide channel?
Should I use a washer between the slider boss and slider to "raise" the height of the upper boss closer to the 12mm quoted in the Service Notes?

I also have a question about lubricants for the lift mechanism. The Service Notes say to use Vaseline however, I've never thought of that as a very "automotive" product. I read that petroleum based grease can cause plastic parts to break down so that rules out standard stuff like LM grease. White Lithium grease seems to be suitable for metal and plastic. What have members used to lubricate the window lift channel and front and rear guide channels?

Thanks in anticipation - this has been a frustrating, expensive and time consuming exercise so far and the doors are still in pieces!!

[lotustonybassplayer]

Hi I don't know if you have seen Toby's vids on youtube ? The Lotus Elan mM100 Restoration series, there is one on the door glass that, might prove useful to you.

[Paul GC]

Hello - Yes I have watched some of the M100 restoration series on YouTube and it was useful to see the inside mechanism. Thanks!