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  1. #1

    Default DOT 5.1 Brake fluid

    has anyone switched their brake fluid to DOT 5.1. I understand that DOT 5 can not be mixed with DOT 3 or 4, but DOT 5.1 can be. I am doing a fluid flush on my truck and wondered if anyone has used the newest stuff. it is supposed to not attract moister like the DOT 3 and 4 fluids do. Opinions?

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  2. #2
    Jr. Engineer Jamm3r's Avatar
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    Dec 2012
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    Minneapolis area
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    Default

    Used DOT 5 in a 1949 Diamond T pickup I restored once. It worked out OK, but we were replacing all components in the brake system anyway so there was no concern of cross contamination.

    Plenty of people hate it but it worked out OK for us. On the other hand, I find that DOT3/4 work out fine for me too
    Minneapolis area - 1997 K2500 regular cab long bed + 8.5' Western Unimount plow + modified transmission + 2nd battery + modified camper charge circuit + 1971 Cayo camper -and- 2004 4x4 Suburban 2500 8.1 + Maxbrake controller + 2nd battery + modified trailer charge circuit + Reese receiver, pulls 30' Airstream trailer

  3. #3

    Default

    Quote Originally Posted by Jamm3r View Post
    Used DOT 5 in a 1949 Diamond T pickup I restored once. It worked out OK, but we were replacing all components in the brake system anyway so there was no concern of cross contamination.

    Plenty of people hate it but it worked out OK for us. On the other hand, I find that DOT3/4 work out fine for me too
    I am thinking that I will just go with a dot 3/4 synthetic.

  4. #4

    Default

    I used DOT 5.1 on a 70 Impala a few weeks ago after being recomended by the Tech guys at Prestone.
    The car was a light restore that I was trying to flip without spending a fortune on getting it road worthy.
    The brake system looked and worked good but my concern was the hydraulics probably hadnt had any maintenance in the life time of the car.
    I flushed it with DOT 5.1 then serviced it up.
    I put 1500 miles on the car before selling it and found no issues, as expected the the brakes were much more responsive after the flush.
    I know the new owner so I certainly keep up on any future issues that may come up with the brakes.

  5. #5

    Default

    Anyone know the tech specs between DOT3/4 and 5?

  6. #6

    Default

    fluid

    DOT 3

    Glycol
    Boiling point
    dry
    over 205℃
    Boiling point
    wet
    over 140℃
    Viscosity
    100 C
    over 1.5cst
    Viscosity
    -40C
    under 1500cst
    PH

    7.0-11.5
    DOT 4 Glycol over 230℃ over 155℃ over1.5cst under 1800cst 7.0-11.5
    DOT 5.1 Glycol over 260℃ over 180℃ over 1.5cst under 900cst 7.0-11.5
    DOT 5 Silicon over 260℃ over 180℃ over 1.5cst under 900cst 7.0-11.5


    This is what I could find quickly. It is in degrees Celsius so to convert to Fahrenheit you need to multiply by 1.8 and add 32. So, 155C= (155x1.8)+32= 311F. I have seen different companies list different boiling points.

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