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Lets start a fight- Brake Fluid

Discussion in 'Early CJ5 and CJ6 Tech' started by Howard Eisenhauer, Feb 16, 2014.

  1. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor


    That works for me... my Harley, jeeps, and antiques spend long periods idle each winter and DOT#5 has given me no trouble, and zero brake maintenance issues.
     
  2. GeoffreyL

    GeoffreyL Well-Known Member

    I use whatever's cheapest at the time cause i know its gonna all leak out.....
     
  3. Vanguard

    Vanguard Take Off! Staff Member

    I vote for the used french fry oil. Just remember to add me as a beneficiary on your insurance first. :D
     
  4. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Ain't as crazy as it sounds :)

    Some cars (Rolls IIRC) use "mineral oil" from a common reservoir for brake fluid/hydraulic suspension purposes.

    So, why don't cars use regular hydraulic oil for brakes?

    Enquiring Minds Want to Know...

    H.
     
  5. Mike S

    Mike S Sponsor

    Lots of aircraft use mineral based hydraulic oil in the brakes.

    http://www.aircraftspruce.com/catalog/lgpages/aeroshell_bflu.php
     
  6. Vanguard

    Vanguard Take Off! Staff Member

    My BMW 530i used mineral oil in the power steering.
     
  7. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    It occurs to me that the results of this poll are bound to be skewed... because there is a group we are not hearing from.

    ...Many people who really found out the truth died in the crashes.
     
  8. Chuck

    Chuck Sponsor

    DOT 3 because it works.
     
    Lockman likes this.
  9. Long&Low

    Long&Low Active Member

    Ditto, its just better than Dot3
     
  10. CJ Ollie

    CJ Ollie Member

    I restored a 1950 GMC and used Dot5 fluid in all new components and never had an issue, plus I bought it at cost because I run a Harley-Davidson dealership. The truck was driven only on nice days and parades and I never had an issue with the brake fluid or components in the 15 years I owned it.
    Harley no longer uses Dot5 and now uses dot 4 in all the new motorcycles because of the heat issue, brake responsiveness and ABS. I have been thinking about this issue as well since I am going through my build and upgrading the brakes from drum to power disc brakes. I will also have a hydraulic clutch as well so I want to use the same fluid for ease of carrying supplies. I am leaning towards Dot3 and flushing it every so often, not really sure which way to go yet through.
     
    Lockman likes this.
  11. termin8ed

    termin8ed I didn't do it Staff Member

    I had 5 in my jeep but flushed it out and went back to 3. Its easy enough to flush out every now and then and I don't have to worry about water collecting in one spot.

    Plus working at a dealership I can get dot 3 pretty easily8)
     
    Lockman likes this.
  12. nickmil

    nickmil In mothballs.

    Depends on the use. Put DOT 5 in an abs equipped vehicle and see what happens.


    Sent from my iPhone
     
  13. nickmil

    nickmil In mothballs.

    The "mineral oil" you are referring to is typically "Girling" fluid.
    A Brit thing common in many British vehicles but others too. I've seen some '80's and '90's Jeep that required it for clutch hydraulic systems.

    Talk to the engineers that design the systems. Bet they could tell you. But when you think about it, brake fluid IS hydraulic fluid. And cheap.


    Sent from my iPhone
     
  14. Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

    Every time I think I know something, I find out I don't know :poo:. I used Dot 5 because I didn't want any leaks to wrinkle my new paint on my chassis. I haven't had any issues with Dot 5 yet., YET. But I am still learning with the help I get from this site. Thanks a lot Guys.
     
  15. Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

    My thinkin' is to use Dot 3 on our early CJ's . That's what was used when they were Born with and it works. And yes, the brake fluid that is left on earlier paint can soften it, but it's not exactly like acid. Flush your brake systems every 2-3 years . If anyone has that much brake fluid on their paint then they have a bigger problem? Keep it simple , Sailor.... We often have bigger mechanical s to work on. I have always believed in P. M. & this is one of those category's.:whistle:
     
  16. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    FWIW I went with the 5, it works fine- no sponginess & the MC reservoir is sealed with a diaphragm to keep the moisture out.
     
  17. Jrobz23

    Jrobz23 Member

    We ran DOT5 in our road-track race car. No fade to speak of.

    If setting up a new system with spiffy new parts, I’d do DOT5.
     
  18. Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

    As wilwood states, dot 5 was developed for classic cars to eliminate the eventual paint peel/ wrinkle. Should be just fine for your jeep and unless your doing something wrong; should never get too hot.
     
    Tom_Hartz and Lockman like this.
  19. Tom_Hartz

    Tom_Hartz Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I restored a 69 Bronco with a complete new system and used dot 5 to protect the paint. Four years later and everything is just fine.
     
  20. Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hey, ya'll .... Not to be a wise guy here, but what ' paint ' are we trying to protect ? Inside the sealed Brake system plumbing ?
    Like I said earlier, & I never claim to be an expert, but this is from common sense & from my longtime experience with brake systems. Yes, over time, leftover & uncleaned up Dot 3 or below brake fluid can softened & stain painted surfaces. However , it does not react immediately like acid or molten lava !
    Wash any spill immediately with lots of water. Water dilutes it down quickly to not a worry. Alas, some older lacquer paint is more susceptible to brake fluid than the present day paints, but again washing it away will mitigate & most likely stop any damage.

    Disclaimer : A quart dumped over the hood of your Jeep may be another story, but I have met zero people on this forum that would ever even set themselves up for that type of accident ?
    Thanks,
    Richie-----Lockman
     
    Last edited: May 5, 2019
    Tom_Hartz likes this.