For the brake fluid part, may I suggest a search under " brake fluid flush ".
On the sparkplug issue:
1. If you are getting Bosch F7KTCR, there is no " adjusting" to do.
2. I normally like to change plugs on an aluminum head engine when it's cold.
3. Apply a VERY small amount of anti-seize compound on the plug threads before installing them.
4. Use a little dab of dielectric grease on the plug boots, before you re-connect them.

P.S. Welcome to the forum.

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2007 C 230 Sport.