The more precise way to determine when to change brake fluid is by measuring moisture content. A change every 2 years is certainly safe but typically excessive. This isn't brand specific - I also plan to test my other car, which is now just 14 months old.tim1999 wrote: ↑Wed Jun 22, 2022 7:09 pmMany MB models require a brake fluid change at every B service interval which drives up the price as well. Plenty of other makes of cars out there that have much longer intervals (Lexus included).neilpilot wrote: ↑Wed Jun 22, 2022 2:57 pm The "B" service is the "A" service PLUS engine air & cabin filters. Once again no special tools or talent is required. I completed the "B" service on my 2016 GLC300 in May. I used OEM filters and Mobil 1 Euro formula synthetic oil, and my total cost was under $100. The first time I did the "B" service it took me about 2-3 hours since it was my first on the GLC, but this time it was done in about 1-1/2 hours. I work slowly, but still probably spend less time completing the maintenance than if I waited at the dealer.
When I owned the C240 I changed brake fluid approximately every 3 years, not necessarily during B service. I just about never use a dealers for service beyond recalls and warranty repairs. They will often recommend various additional services, some questionable (i.e. gasoline additives) since it's good for their business.
Since we replaced the C240 with the GLC300, I've started to test the moisture content of all my auto's brake fluids annually with a target of changing fluid if/when the water content is >=3%. I ended up changing the fluid at year 5 on the GLC300, even though it still wasn't quite up to 3%.
This is similar to the tester I use: https://www.amazon.com/Diagnostic-Hydra ... s9dHJ1ZQ==
Some say you can use a VOM to test fluid, but I haven't tried that method. https://autoedu.info/en/auto-mechanic/b ... e-fluid-1/