Keeping Your 3 Series Origami Top in Tip Top Shape

On behalf of Kat and myself you are welcome.
Now post some pics of your convertible!!

Im noticing a creaking sound from drivers side of the joint between the first and second roof panel. If the window is up its not as bad. With window down if i tug on roof i can induce the creak sound. Anyone else have this issue and a fix for it. It may just need a little grease

Every BMW owner in northern states should have Gummi Pflege and apply on door seals every winter. It resists freezing and sticking in cold climate areas. Amazing product!

Hello,

Firstly, thanks for the detailed post! I have a question relating to one of your of the comments in the opening post - 'Silicon is a natural enemy of rubber. It makes rubber swell and fracture'

If the above is true why are there so many Silicon based products for sale designed to protect rubber?

I was planning on buying this product - http://www.halfords.com/webapp/wcs/s...egoryId_228374

but when I read this post I began to think twice? Also isn't Gummi Pflege a type of Silicon?

Any clarification on this topic would be appreciated.

Thanks,
BMW2907

I defer to Kat on this since she is a chemist and I am an engineer.
However I find this article which is very old to be very useful to understand how to keep your top in great shape.
http://forums.vwvortex.com/showthread.php?3087297
I know some silicons contain acid which having a low pH is bad news for rubber and anything that touches it.
I do use Gummi Pfledge and Krylox as well with good results.
Hopefully Kat can amplify her input to clarify what she meant...

Originally Posted by bmw2907

Hello,

Firstly, thanks for the detailed post! I have a question relating to one of your of the comments in the opening post - 'Silicon is a natural enemy of rubber. It makes rubber swell and fracture'

Any clarification on this topic would be appreciated.

Thanks,
BMW2907

First of all, I am not a polymer chemist, my area of experience is more petroleum based; but as such, I'll give you my understanding of the issue.

The "rubber" seals on our cars are a synthetic polymer (elastomer) called ethylene propylene diene monomer. EDPM, aka 'M-class' rubber. With all those -enes contained within the chemical structure, there are a fair number of double bonds (potentially reactive sites). The problem becomes when the silicon which is not inert is introduced to the elastomer. Potential for breaking the exsiting double bonds and creating new bonds with the silicon is introduced. Now, add in the chance that the silicon protectant being employed is oil based not water based. Hydrocarbons and rubber don't play nice with each other at all. I see this every day in the lab when we receive samples (usually gasoline spills) from environmental labs, and they have put the samples in glass vials with a rubber septum cap and the septum is swelling up and oftentimes leaking. Third problem, UV exposure. That's pretty much unavoidable. But just like in our bodies, UV exposure will promote free radical formation which becomes another hot spot for unfavorable chemical reactions to take place. With all this uncertainty, and not being privy to the proprietary chemical formulations of all the different rubber protectants on the market, the safest and most prudent seems to be to go with what is known to work. Gummi Pflege and Krytox each get a seal of approval with that regard.

ps: Years ago, in an effort to "do the right thing" I weekly treated the tires on my car with a widely available in autoparts stores product which was silicon based. About halfway through the tires' life span I noticed that all four tires were starting to split in a place one would not associate with wear. Turns out they were diagnosed with "dry-rot".
The cause of the dry rot?
My vigilant usage of chemicals that were in reality hastening the demise of the tires. Interestingly, the product I was using is no longer available.

Lesson learned.

And, finally to answer your question, to my knowledge - Gummi Pflege is not a silicon containing product. If you have information contrary I would be interested. (You now have me curious to do the experiment and do an analysis of the gummi pflege looking for the proper repeating pattern we see in our simulated distillation analysis when silicon is present.)

Hope this helps.

Thanks for the great information. It seems that the Gummi is easier to apply than Krytox. Is this the case, and is the extra work for Krytox worth the effort? (Last longer between applications, etc)

Originally Posted by DarkHorseMBA

Thanks for the great information. It seems that the Gummi is easier to apply than Krytox. Is this the case, and is the extra work for Krytox worth the effort? (Last longer between applications, etc)

I tend to use the Gummi on a weekly basis and the Krytox on a quarterly basis. In the winter, when the car doesn't get washed as regularly I tend to use the Krytox a little oftener. It's like a deep conditioning. My car is rattle and squeak free and almost 4 years old; so for me, the "extra work" worth the effort. FWIW: The Krytox also plumps the seals up enough to prevent a teeny little drip I get at the passenger side if the seals get too dehydrated.

Originally Posted by Nordic_Kat

The Krytox also plumps the seals up enough to prevent a teeny little drip I get at the passenger side if the seals get too dehydrated.

Thanks!

BTW I saw that one of my tensioning cords is fraying. Did your dealer replace them all or just the frayed ones, and how long did it take? My local dealer's service stinks I have to twist their arm to get them to accept something needs replacement.



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I had both(?) replaced as both (if you mean rear) cords replaced under warranty.

From what I've gathered from other folks in Austin and San Antonio your dealerships aren't as accustomed to issues with the hardtop as our Houston dealerships are. Not sure about fraying issues on a 2011 as my understanding was they redesigned the cords with the LCI so with a 2011 you should have the new version of cords. The replacement cords I have are holding up very well.

PM me if you want details.

This is a great post... I notice the seal are all dusty and sandy so will probably use a wet cloth to wipe it off first before applying Krytox. I am wondering if I should wait for it to dry off before apply or it does not matter.....


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