In my owner manual (cobalt ss/sc 2006) they says that to put only dot 3 fluid. Can a dot 4 fluid can be harmful to the brake system?
thanks
thanks
brake fluid dot 3 to dot 4 ?
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dot 4 should be fine. it has a higher boiling point than 3. just dont use dot 2. or 5 (silicone)
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Yeah you can find many DOT 4 Bottles list both 4 and 3.
Ford Dot 3 exceeds Dot 4 but only lists 3 and they are the same fluid base.
Ford Dot 3 exceeds Dot 4 but only lists 3 and they are the same fluid base.
Yep, but if your in doubt then use Valvoline or Prestone which are readily available and say right on the label: DOT3,4.
afaik, DOT 3 lasts longer.
DOT 3...DOT 3 1/2...what ever it takes....
what matters is doing a flush according to your owners manaul
dot 3 or 4 will be fine
dot 3 or 4 will be fine
Have any of you seen a DOT 4 bottle that does not say DOT 3 and 4?
I don't believe his Owners Manual specifies flushing the system, although I think it is a good idea to do it every 2-3 years.
Originally Posted By: mechtech2
Have any of you seen a DOT 4 bottle that does not say DOT 3 and 4?
Yes--The O'Reilly "Brake Best Select" fluid only says DOT4. I am using it in a DOT3-spec'ed GM vehicle. It's been working fine for five months now.
Have any of you seen a DOT 4 bottle that does not say DOT 3 and 4?
Yes--The O'Reilly "Brake Best Select" fluid only says DOT4. I am using it in a DOT3-spec'ed GM vehicle. It's been working fine for five months now.
You have to work the brakes insanely hard to bring the brake fluid temps up to boiling point of dot 3. The #3 fluid has an advantage over #4 in that it will resist absorbtion of moisture better than #4. Moisture in the fluid system lowers the boiling point at the same time causing corrosion. We all know nobody changes there brake fluid in the real world. They get away with it because they have #3 in there.
Originally Posted By: willix
You have to work the brakes insanely hard to bring the brake fluid temps up to boiling point of dot 3. The #3 fluid has an advantage over #4 in that it will resist absorbtion of moisture better than #4. Moisture in the fluid system lowers the boiling point at the same time causing corrosion. We all know nobody changes there brake fluid in the real world. They get away with it because they have #3 in there.
Water has nothing to do with the difference in boiling point between DOT3 and DOT4. They are measured dry and wet.
Minimal boiling points for these specifications are as follows (wet boiling point defined as 3.7% water by volume):
Boiling point ranges Dry boiling point Wet boiling point
DOT 3 205°C (401°F) 140°C (284°F)
DOT 4 230°C 446°F) 155°C (311°F)
DOT 5 260°C (500°F) 180°C (356°F)
DOT 5.1 270°C (518°F) 191°C (375°F)
You have to work the brakes insanely hard to bring the brake fluid temps up to boiling point of dot 3. The #3 fluid has an advantage over #4 in that it will resist absorbtion of moisture better than #4. Moisture in the fluid system lowers the boiling point at the same time causing corrosion. We all know nobody changes there brake fluid in the real world. They get away with it because they have #3 in there.
Water has nothing to do with the difference in boiling point between DOT3 and DOT4. They are measured dry and wet.
Minimal boiling points for these specifications are as follows (wet boiling point defined as 3.7% water by volume):
Boiling point ranges Dry boiling point Wet boiling point
DOT 3 205°C (401°F) 140°C (284°F)
DOT 4 230°C 446°F) 155°C (311°F)
DOT 5 260°C (500°F) 180°C (356°F)
DOT 5.1 270°C (518°F) 191°C (375°F)
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^^^ Thanks for posting that information. I always thought DOT4 was a higher standard than DOT3, and thus could be used for both applications. I have some Prestone Synthetic DOT4 which advertises higher dry/wet boiling points on the bottle.
DOT5 (Silicone) is what Harley used for their spec fluid for awhile, now it's DOT4. AFAIK, 4 and 5 should not be mixed.
DOT5 (Silicone) is what Harley used for their spec fluid for awhile, now it's DOT4. AFAIK, 4 and 5 should not be mixed.
I started using Prestone Disk brake fluid in 1966. I am not sure it was labeled DOT 4 then. I have used it ever since in DOT 3 specified systems. Never had a problem. Never flush the fluid either.
Originally Posted By: labman
I started using Prestone Disk brake fluid in 1966. I am not sure it was labeled DOT 4 then. I have used it ever since in DOT 3 specified systems. Never had a problem. Never flush the fluid either.
Sorry , but 1966? we would have liked to see a little longer trial if you don't mind. Will the people from the 1940's please speak up....
I started using Prestone Disk brake fluid in 1966. I am not sure it was labeled DOT 4 then. I have used it ever since in DOT 3 specified systems. Never had a problem. Never flush the fluid either.
Sorry , but 1966? we would have liked to see a little longer trial if you don't mind. Will the people from the 1940's please speak up....
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I have used Dot4 since the 60s with no issues. I became involved with British roadsters back then. They called for Dot4 so I have always used it in every thing. Triumph started putting disc brakes on the TR-3 in 1955. I started driving in 1960 but don't remember what brake fluid I used then.
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I have used Castrol GT-LMA for many years. Has always peformed great. It has very low moisture activity. I have used Prestone in a pinch.
http://www.castrol.com/castrol/sectionge...w=Brake%20Fluid
http://www.castrol.com/castrol/sectionge...w=Brake%20Fluid
Originally Posted By: endeavor to persevere
I have used Dot4 since the 60s with no issues. I became involved with British roadsters back then. They called for Dot4 so I have always used it in every thing. Triumph started putting disc brakes on the TR-3 in 1955. I started driving in 1960 but don't remember what brake fluid I used then.
My first car with disk brakes was a 64 TR-4. My last one with front drums was a 68 Chevelle.
I have used Dot4 since the 60s with no issues. I became involved with British roadsters back then. They called for Dot4 so I have always used it in every thing. Triumph started putting disc brakes on the TR-3 in 1955. I started driving in 1960 but don't remember what brake fluid I used then.
My first car with disk brakes was a 64 TR-4. My last one with front drums was a 68 Chevelle.
#3 is just fine. It make no difference if you use #4. That would be fine. No harm done. I have experienced the long pedal & no pedal.
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1968 TR 250 100% frame up restoration. this one was built in the last week of production.
Yeah, I did all the work......
Yeah, I did all the work......
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