Now, how much is needed to do the flush?

 

2 bottles RBF600 or 1 bottle of ATE (they're twice as big)

 

Thanks Mike. They sell the ATE blue here in a 1 liter container, which should be more than enough, no?

 

This is not true. "Higher" spec fluids are manufactured differently and contain less dissolved air, making them less compressible. This has nothing to do with how long they can stay in the vehicle.

Chris

 

2 500mL bottles usually does it, but have a 3rd on hand just in case. Use the ATE blue if you want to stain your master cylinder reservoir. Otherwise, stick with non-dyed fluids.

Chris

 

The Motul will work, for sure, but be a bit more $$$. Castrol makes a good DOT4 as well. Again, there are only a handful of chemical plants in the world that make brake fluid, but the devil is in the details. Each brand can specify what blend they want and how unsaturated with moisture and/or air. Keep in mind that the cheap stuff is not packaged in nitrogen, so you'd be lucky to get the wet boiling point right out of the bottle.

Chris

 

Does the gold stain too?

 

No -- dyes are not added to the gold.

 

Thanks Chris for the help.

 

I have absolutely no qualification in terms of brakes or brake fluid, but I HAVE always been told exactly what Mike said, that Higher spec fluids need to be changed more often

 

No worries. As always, there is a lot of mis-information out there. That warning did come originally from some shred of truth, but it has gotten skewed over the years as to why.

The reasoning behind changing the better fluids more often is that they tend to be used in cars that people push harder -- track days, canyon carving, etc. Heating the fluid to extremes and cooling it back down repeatedly tends to increase the amount of moisture that gets pulled into the fluid -- think condensation. So it's not that the fluid that is more hygroscopic, it is the actual brake usage that comes into play. The only exceptions are the LMA fluids, but those are not ideal for performance use anyway. As mentioned earlier, quality stainless steel lines will dramatically slow moisture ingress due to the Teflon liner.

So, rather than the fluid spec, it is driving style that dictates a more frequent fluid change. The track junkies know they will be going through fluid much more often than they would with a standard street vehicle. Since boiling point, low compressibility and recovery are paramount, they will spend a little extra on the better fluids. As with many things, you generally get what you pay for.

Chris

 

^ahhhh ok, that makes perfect sense Chris. Thanks for the explanation.

 

i run motul rbf600 and change it out every year/20k miles without issue including a few track days.

 

Sorry to dig up an old thread but this is exactly my question. I want a more defined answer, motul is the brand of choice fine. What is the difference btw rbf600 and dot 5.1?

 

RBF600 (and RBF660) are for racing and ultra-high performance use. DOT5.1 fluid has a high boiling point, but not quite as high. Plus, 5.1 has a viscosity particularly suited for ABS systems for faster response. Essentially, if you are on the street and might do HPDE events, 5.1 would be a great choice. Serious track guys will need to move to the 600 or 660.

Motul is very good, but there are a couple of others also worth considering.

Chris