A little more for everyone so that they understand why some have said not to use DOT 5 fluid.
If you want to look at brake fluids from a chemical standpoint DOT 3 fluids are based on glycol and glycol esters. DOT 4 fluids are much like DOT 3 fluids, but also contain borate esters. There is another rating called DOT 5.1 that consists of borate esters.
Notice that water is not listed as a component of brake fluid. Water boils (sea level air pressure) at 212 degrees F (100 C). Since the disk rotor can and will generate over 1000 degrees (F) of heat and transfer 400 degrees or more to the caliper water is not a good fluid to choose.
Why do I mention water? The chemistry of DOT3 and DOT 4 brake fluids attract water. Right out of the air. In fact the anti-freeze you use is probably glycol based just because it mixes well with water.
The difference between the DOT (Department of Transportaion) ratings of brake fluid are the boiling point ranges that they achieve both dry (no water absorbed) and wet (about 3-4% water content). For DOT 3 the dry boiling point is at least 401 and the wet 284 degrees. DOT 4 raises the bar to 446 and 311 respectively. Those are the DOT ratings mind you , and there are high performance brake fluids that exceed those ratings.
The cost of brake fluid can vary as well from less than $0.20 an ounce to over $2.00 an ounce. Some of the high performance fluids are rated well over 500 (to almost 600) degrees boiling point dry. Wet boiling points will also vary, but be well over 400 degrees.
The higher boiling points are critical to those of you that wish to spend time on a race track. Once you boil your brake fluid it will not recover and you MUST bleed and change out the fluid.
The every day driver will find brake performance just fine by sticking with the fluid that the dealership recommends unless they use their vehicle to the extreme, such as a newspaper delivery route or negotiating their way down curvy mountain roads. You will know because the brake pedal will start to feel mushy as the fluid overheats and the pedal may even go to the floor.
So what is the big deal? The big deal is that most of us never flush and replace our brake fluid. In fact, if you go to a garage and have a “brake job” done it is highly unlikely that they will do much more than bleed the brake lines. This means that the old – water soaked – tired – brake fluid will still be there. The water can react to oxidize brake components from the inside out. What you should do, probably once a year, is have the old fluid flushed and completely replaced with fresh brake fluid.
Now, which one is best??? You should do your own research, but I have seen many comparisons in researching which brand to recommend. While I sell AMSOIL and they do offer a great product, I have found that there are several brands out there that offer products with higher boiling points. Since the boiling point of the brake fluid is going to be the main standard by which to judge them, that is what I look at when I was looking for a product to recommend. AMSOIL DOT 4 performance racing brake fluid has a dry boiling point of 580* dry and 410* wet. The DOT minimums for DOT 4 are 446* and 311*. About the only other brake fluid that I have found that has a higher overall boiling point than most others happens to be the Wilwood EXP600 DOT 4 Fluid with a dry boiling point @ 626* dry and 417* wet. However, it is NOT CHEAP. a 16.5 ounce bottle will cost you $20 or so before shipping or sales tax and you will need at least 2-3 bottles on hand to ensure a proper full flush.
Hope this helps everyone with knowing a little more about their brake fluid. But like stated, DO NOT USE DOT 5 or 5.1 in your truck.
If you want to look at brake fluids from a chemical standpoint DOT 3 fluids are based on glycol and glycol esters. DOT 4 fluids are much like DOT 3 fluids, but also contain borate esters. There is another rating called DOT 5.1 that consists of borate esters.
Notice that water is not listed as a component of brake fluid. Water boils (sea level air pressure) at 212 degrees F (100 C). Since the disk rotor can and will generate over 1000 degrees (F) of heat and transfer 400 degrees or more to the caliper water is not a good fluid to choose.
Why do I mention water? The chemistry of DOT3 and DOT 4 brake fluids attract water. Right out of the air. In fact the anti-freeze you use is probably glycol based just because it mixes well with water.
The difference between the DOT (Department of Transportaion) ratings of brake fluid are the boiling point ranges that they achieve both dry (no water absorbed) and wet (about 3-4% water content). For DOT 3 the dry boiling point is at least 401 and the wet 284 degrees. DOT 4 raises the bar to 446 and 311 respectively. Those are the DOT ratings mind you , and there are high performance brake fluids that exceed those ratings.
The cost of brake fluid can vary as well from less than $0.20 an ounce to over $2.00 an ounce. Some of the high performance fluids are rated well over 500 (to almost 600) degrees boiling point dry. Wet boiling points will also vary, but be well over 400 degrees.
The higher boiling points are critical to those of you that wish to spend time on a race track. Once you boil your brake fluid it will not recover and you MUST bleed and change out the fluid.
The every day driver will find brake performance just fine by sticking with the fluid that the dealership recommends unless they use their vehicle to the extreme, such as a newspaper delivery route or negotiating their way down curvy mountain roads. You will know because the brake pedal will start to feel mushy as the fluid overheats and the pedal may even go to the floor.
So what is the big deal? The big deal is that most of us never flush and replace our brake fluid. In fact, if you go to a garage and have a “brake job” done it is highly unlikely that they will do much more than bleed the brake lines. This means that the old – water soaked – tired – brake fluid will still be there. The water can react to oxidize brake components from the inside out. What you should do, probably once a year, is have the old fluid flushed and completely replaced with fresh brake fluid.
Now, which one is best??? You should do your own research, but I have seen many comparisons in researching which brand to recommend. While I sell AMSOIL and they do offer a great product, I have found that there are several brands out there that offer products with higher boiling points. Since the boiling point of the brake fluid is going to be the main standard by which to judge them, that is what I look at when I was looking for a product to recommend. AMSOIL DOT 4 performance racing brake fluid has a dry boiling point of 580* dry and 410* wet. The DOT minimums for DOT 4 are 446* and 311*. About the only other brake fluid that I have found that has a higher overall boiling point than most others happens to be the Wilwood EXP600 DOT 4 Fluid with a dry boiling point @ 626* dry and 417* wet. However, it is NOT CHEAP. a 16.5 ounce bottle will cost you $20 or so before shipping or sales tax and you will need at least 2-3 bottles on hand to ensure a proper full flush.
Hope this helps everyone with knowing a little more about their brake fluid. But like stated, DO NOT USE DOT 5 or 5.1 in your truck.
