Keep in mind the Commander has recommended for brake fluid DOT 3. Sure you can use DOT 4 if you want, it has higher boiling points, but DOT 3 lasts longer and absorbs less moisture than DOT 4. So, think about it, DOT 3 really is the better fluid, unless your brakes get so hot they require the higher temp, but shorter lasting, less durable DOT 4.
As well, there are several brands of DOT 3 and 4 fluid, that use the better additives to achieve the characteristics that is needed, so they are the best of both worlds, they absorb moisture slower than DOT 3, as durable and can go to temps even higher than DOT 4. Castrol GTLMA is one, Valvoline DOT 3 & 4 Brake Fluid is another.
Like mentioned, the brake fluid will absorb moisture right out of the air, even if you don't open the brake system, it can suck right through the seals.
The good about brake fluid absorbing moisture is that if water ever got into your brake system, instead of descending to the lowest point of the lines and laying there, rusting a hole in the line to make your brake fails, it will absorb the water and hold it in the fluid. The bad about that, over the years the brake fluid will get more and more moisture absorbed in it, that will lower its boiling point temp dropping and one day when you really task your brakes and get them really hot, the fluid may boil and turn to steam and steam compresses, and thus no brakes. As well, the moisture in the fluid will allow sludge and gum to form and can start some corrosion in parts of the brakes.
Also, remember, when the manufacturer says that a fluid will last the life of the vehicle, they are assuming the vehicle is only going to last 100k miles. So change your brake fluid.
Power Steering fluid is a good one to change as well before the life of the vehicle. And if you have a Hemi with the hydraulic driven fan, that is powered by the PS system, and how often those have failed, it might be good to replace that fluid with the Correct Fluid (the Commander uses a hybrid PS/Hydraulic fluid you can only get from the Dealer).
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.