Dot 3 & 4 brake fluid

Discussion in 'Touring Models' started by turnerbend, Jul 6, 2012.

  1. turnerbend

    turnerbend Active Member

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    Getting ready to flush my brake system. System calls for Dot 4 fluid.
    Checked for Dot 4 fluid at Advance and Autozone and all they had was Dot 3 & 4. Is it OK to use this fluid or do I need to keep looking for DOT 4 fluid??
     
  2. Jack Klarich

    Jack Klarich Expert Member

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    Dot 4 would be the best choice here it has a higher boiling point f the manual is saying small amounts of DOT3 can be used, what they are most likely saying is if you find yourself with low brake fluid and only DOT3 is available, it is better to use that than to not have brake fluid.

    Once you get back home though you need to get the recommended DOT4 back in the system by bleeding the system and filling with DOT4.

    As already stated, DOT4 handles higher heat. If your car is calling for DOT4, that means that the manufacturer does not feel comfortable that the braking system will not raise the brake fluid above a temperature that DOT3 can handle.

    Another point to make here is there are two boiling temperatures for brake fluid, Dry and Wet.

    When you've just replaced your brake fluid and the system has been properly bled, you are working at the Dry boiling temperature. Over time, water works its way into the system through age, heat cycling, through the hoses, etc. You are then working at your Wet boiling point for the fluid.

    So again, if you get stuck in a spot where you need to put some new brake fluid into the system and all you have available is DOT3, most likely at that point your DOT4 has degraded some and the fresh DOT3 will be close to where the DOT4 is at, but this won't stay true, the DOT3 will degrade once in the lines so the above statement of replace it as soon as possible holds true.
     
    1 person likes this.
  3. turnerbend

    turnerbend Active Member

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    Thanks Jack
     
  4. Jack Klarich

    Jack Klarich Expert Member

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    :s Ride safe, don't take chances with brakes
     
  5. Midnight Reign

    Midnight Reign Active Member

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    I think what he may have been asking is, there is now on the shelfs of auto parts stores a brake fluid actually labled "DOT 3&4". And the implication is it can be used in either system. And by extension could be mixed with either system. I could be wrong here but thats how I read it

    And in response to the original question, if it were me I would continue to look for straight DOT4 as called for by the MoCo. just my opinion.
     
    Last edited by a moderator: Jul 6, 2012
  6. Jack Klarich

    Jack Klarich Expert Member

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    Valvoline/32 oz. DOT 3 and 4 brake fluid (601458) | Brake Fluid | AutoZone.com This may be misleading, you should read the labels closely there is a difference in the boiling point, this will change how quickly it will absorb moisture also. There is also a choice of synthetic fluid as I am sure Tank will have a link to Amzoil s answer to this:s
     
  7. turnerbend

    turnerbend Active Member

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    I went to a local motorcycle shop and got the regular DOT 4 fluid. The Advance Auto sales person was saying that the Dot 3&4 was all you could get now and that's what everybody use in the motorcycles the requires Dot 4.
     
  8. Webbtron

    Webbtron Banned

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    I was starting to think that it was another deal like new formula Pledge.
     
  9. FLIPBEL

    FLIPBEL Member

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    Got dot 4 about 3 weeks ago at O'reilly autoparts.