well said I learn more and more on this site everydayPT said:If you upgrade to a higher DOT-level brake fluid, you need to make sure that your brake lines/joints can handle it... if not, you might bust a brake line under heavy breaking... this would mean that you would have serious braking power, and then SNAP!!! You will have NO braking power... and you would hopefully still be able to E-Brake to a stop. All modern cars are designed with redundant brake systems, so at most, you will lose only 2-brakes at a time... but nonetheless, busting a brake line is a bad thing.
Higher DOT fluid compresses less and can withstand higher temperatures without losing their compression propertires. Higher DOT fluids thereby increase braking power and brake feel (unless you have brake-by-wire which Altimas don't). Stock Altimas come with DOT-3 fluid, and can safely handle DOT-4... but I wouldn't go with DOT-5 unless you plan to replace your rubber brake lines with steel-braided lines as well. The solid-pipe lines under the car and in the engine-bay should be OK, but I'd make sure that the joints are still sealed well.
I would do a full brake flush , remove all of the old fluid from the master cylinder , add the Motul , then bleed the heck out of the brakes , make sure you have to refill th Master cylinder at least once per wheel .....ribita said:Now I'm planning to use Motul 600 Dot 4. Should I wash out my Dot 3 first or just mix Motul 600 to Dot 3?
If Motul 600 is DOT-4, then it should be OK. I've been using DOT-4 brake-fluid with the stock rubber hoses and I haven't had any problems yet... I can't use braided brake-lines because that modification is not allowed in my car-class... otherwise I would.ribita said:What about if my brake line is not steel. I think it's still rubber. Does my brake line can handle Motul 600 or do I need to upgrade to aluminum stell lines?