The brake fluid in these cars seems to turn black. In looking at these cars, the online sales sites usually have a picture with the hood open. Many have dark or black brake fluid. The fluid in my '03 with 70k is just starting to take on a little dark tint. Since it has been over 2 years since it has been flushed, I will be having it done in a few weeks. Does anyone know why this happens and anything I can do to prevent it or delay it? Maybe replace the cap or use a certain type of brake fluid?

 

My opinion is black means it may have gone well over 2 years.

From my research, the color should be clear to golden? I had mine flushed at Lexus, and oddly I was only charged $59 (less than a muffler shop). I have a Motive but I don't have a Japanese adapter, or I would have DIY'd. My hunch, based on the price, and based on the time that they physically had the car, is that they simply exchanged the reservoir. Or, maybe they bled out one caliper (I get the drain/fill on the tranny, but imho these other fluids should be completely extracted/exchanged). Because the fluid got darker over a week or so, my hunch is only a portion was replaced. Anyway, 2 years is a good rule to follow as far as replacing brake fluid on any car, because it is hygroscopic, i.e. absorbs water. My BMW fluid is clear, but it is dot 4 synthetic, and I believe the LS is dot 3, so I've decided to not worry about the color and accept golden and dark golden...but I think I will DIY all 4 calipers next time, so I know it's done correctly and not half baked...

p.s. if we really wanted to we could test the old fluid, there are test strips that can be purchased, just that I wonder what benefit it is other than "nice to know," since brake fluid is relatively cheap....I was told that not replacing brake fluid allows its boiling temp to be less favorable, as well as rusting the system from the inside out. When I did my alignment, I came upon an argument by a customer accusing Firestone of padding services, when they replaced someone's brake fluid. They said they would remove the charges, but the customer was still yapping, so I decided to chime in and state my opinion on the 2 yr....

 

I have the Motive 101 also john and I plan to flush the the brakes on both LS's and the GS. I plan to just buy another reservoir cap and drill a hole in the middle and seal it up to create my own adapter.

 

hmmm...this sounds like it could be way more economical! I thought the adapter costs just a little less than an entire unit if one finds a low price....I have the premium one for Euro cars.....it's like a metallic maroon billet cap....

 

Yes the adapters cost way too much and I haven't seen one that's specific to our cars. Hence making my own which was suggested by another member in the GS forum I think. I browse several forums so it's hard to remember where I read certain things.

 

Based on the service records, fluid is about 3 years old. I will be changing the fluid when I have stainless steel brake hoses installed in about 10 days.

 

I am a little shocked that your dealer only charged $59. dollars .every time a call a dealer about anything they have a min. I hour charge of $135. U must have a special dealer.Lucky you

 

Why do you need SS brake hoses?

 

I don't need them. I had them on my previous cars ('97 LS400 and '02 LS430) and liked them. Brakes are firmer. they are a nice to, not a need to. Some believe that after 14 years, the hoses deteriorate resulting in the black tint. While I am not sure about that, they were available at a good price (about $80 for a complete set of Stop-tech hoses) and the brake fluid needs to be done. It is also a good chance to try out a (new to me) independent mechanic that a friend recommended.

 

Generally I don't see brake fluid turn black unless it's right in the caliper area, then it's most likely because of the temperature it operates in daily..plus the square cut piston seal is right there, I think the black rubber seal sheds a little rubber right into the fluid. Brake fluid is hygroscopic and absorbs moisture from the air - which is why it's supposed to be changed every two years - plus manufacturers vent the master cylinder cap (allowing air right in). The reason the fluid is hygroscopic is because if there is water in the system the brake fluid will disperse the water throughout the system, rather than letting it accumulate in one area (which could allow it to boil if it gets hot enough and cause an air bubble). But air will get in other ways (bad lines, hoses, seals, repairs). So you change the fluid every two years because the water that has entered the system lowers the boiling point,which left untreated could be dangerous (in theory anyway, but there are many cars driving around that have never had their brake fluid changed). And it's not a part of any state safety inspections that I know of, and it easily could be...all you have to do is use a test strip to measure the moisture in the fluid.

 

Good information, thank you for posting it. It may be overkill but it is time to change the fluid. I like opening the hood and seeing a clean engine bay with nice honey colored brake fluid in the reservoir.