Register now to get rid of these ads!

How to flush silicone brake fluid out of brakes

Discussion in 'The Hokey Ass Message Board' started by Janius, Sep 26, 2011.

  1. Janius
    Joined: Jul 31, 2009
    Posts: 27

    Janius
    Member
    from New Jersey

    The prior owner of my car thought that silicone brake fluid would solve all of his brake problems. I am rebuilding or replacing almost all of the components except the lines and want to know how to totally remove the silicone fluid that may still be in the lines. What do I use to flush? Regular brake fluid (I am going to DOT 4 when I'm done). Thanks! Janius
     
  2. Frankie47
    Joined: Dec 20, 2008
    Posts: 1,878

    Frankie47
    Member
    from omaha ne.

    Bite the bullet and spring for new lines......if you can't get "ALL" of the silicon out of the old ones you will cross contaminate your rebuilt/new brake components.

    Do you want to chance it???
     
  3. bauschracing
    Joined: Mar 31, 2011
    Posts: 64

    bauschracing
    Member

    silicon brake fluid does not mix with regular brake fluid. When mixed, it form a jell. best to drain then use light pressure and blow out the rest of the silicon.
    Mike
     
  4. oldcarfart
    Joined: Apr 12, 2005
    Posts: 1,437

    oldcarfart
    Member

    rubbing alcohol, find highest % of alcohol vs. water, and then blow thru with brake clean in aerosol cans, never clean any brake parts with anything other than alcohol and designated brake cleaners
     

  5. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 8,922

    mgtstumpy
    Member

    Methylated spirits will do the trick. I flushed all my lines and M/C before blowing out the lines with a HP air line to make sure the new fluid would not be contaminated by residual silicon fluid. Before I bled the system I replaced all the seals. Been on the road for five (5) years without issue.
     
  6. What exactly is silicone brake fluid? I am using dot 3 synthetic and assume it is something completely different........
    For those who know, I am using a 40's braking system, oem style with 40's cylinders and single pot master cylinder (Wagner). Calls for dot 3. Is synthetic dot 3 okay to use?

    Thanks
     
  7. cavemag
    Joined: Jan 8, 2011
    Posts: 210

    cavemag
    Member

    Silicone is dot 5.
     
  8. chrisntx
    Joined: Jan 20, 2006
    Posts: 1,798

    chrisntx
    Member
    from Texas .

    How long does it take to jell? I mixed some in a cup and watched it for weeks and nothing happened
     
  9. noboD
    Joined: Jan 29, 2004
    Posts: 7,771

    noboD
    Member

    I don't know how long, but had it happen. Silicon was added to a truck at work. I had absolutely NO brakes had a hel of a time stopping by turning off the engine. There was a big afterbirth looking glob in the MC.
     
  10. RAY With
    Joined: Mar 15, 2009
    Posts: 3,133

    RAY With
    Member

    True that silicone brake fluid will not mix with regular brake fluid but I have neve seen it jell. I have silicone fluid in a couple of cars and regular in some others. I just mark the MC tops so I dont mix it up. My experience with silicone has been good and I am at 15 years on a mustang brake job with silicone and no bad parts or leaks. I guess its just a choice you have to make. To go from silicone to regular fluid I would blow out the lines with air and regular brake fluid then add the new fluid and go with it.
     
  11. bauschracing
    Joined: Mar 31, 2011
    Posts: 64

    bauschracing
    Member

    I work for the ARMY and years ago, all of the brake systems were changed to silicon. There was still regular brake fluid on the shelfs and we found contaminated systems all of the time until all of the old brake fluid was removed.
    The master cyld would jell as well as the lines and wheel cylds.
    Silicon fluid works good as long as the system is not mixed.
    When you use silicon fluid, you do not have to worry about moisture plus it will not mess up your paint jobs if you spill it.
    Mike
     
  12. outlaw256
    Joined: Jun 26, 2008
    Posts: 2,023

    outlaw256
    Member

    funny you should ask this question as im going the opposite direction from dot 3 to silocone.have fresh painted everything and dont want to chance dot 3 removing paint for me.in my world shiny is good.
     
  13. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 8,922

    mgtstumpy
    Member

    For to add, silicon fluid is not hygroscopic, won't absorb moisture and won't destroy your paint finish. When I had it, the pedal feel was a little softer when compared to conventional fluid that does ruin your paint.
     
    Last edited: Oct 15, 2017
  14. 1934coupe
    Joined: Feb 22, 2007
    Posts: 4,645

    1934coupe
    Member

    All of the previous posts/statements are pretty valid. I have DOT 5 in my 65 Olds for 15 years with no probs at all. Put it in my 67 Chevy when I switched to DB and SS lines and it was a nightmare. I cleaned/flushed it out with alcohol and problem solved. My friend has a 41 Ford restored, 50 Ford PU restored and a model A with a flattie and 39 juice brakes, Dot 5 is all he uses with no problems. In my experience with DOT 5 you have to be very carefull not to shake it or create bubbles in it. It seems to "entrap those tiny bubbles" making bleeding a hassle and I found I couldn't put back in the master what I took out of the bleeders it looked like seltzer.

    Pat
     
  15. Silicone.

    Silicon (no 'e') is a metal material used in integrated circuits (ie; computer processors).
     
  16. monkeyspunk79
    Joined: Jan 2, 2011
    Posts: 553

    monkeyspunk79
    Member

    Absoloutely correct. Denatured alcohol / mehtylated spirits with an blow gun chaser. Works when converting to either system to flush lines completely clean.
     
  17. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,482

    34toddster
    Member
    from Missouri

    Fluid aside, don't you have to use a Dot 5 approved Master? The last master I bought was labeled DOT 3 ONLY? any one know?
     
  18. S.F.
    Joined: Oct 19, 2006
    Posts: 2,895

    S.F.
    Member

    why not just keep the silicon fluid in it?
     
  19. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,025

    Mr48chev
    ALLIANCE MEMBER

    You can buy 70% alcohol in gallons at the Vet supply for a reasonable price rather than buying at the drug store. What Oldfart suggested works either way when you switch from one fluid to the other.
     
  20. amphicar
    Joined: Apr 4, 2006
    Posts: 153

    amphicar
    BANNED

    That MC would be a replacement for a stock system that had DOT3 from the factory. No such animal as DOT5 approved. I run DOT5 in my Amphicars w/o problems.
     
  21. Raven53
    Joined: Jan 12, 2009
    Posts: 442

    Raven53
    Member
    from Irwin Pa

    I had regular dot 3 in my 48 and about every 4 years the wheel cylenders would oxidize up and the rubbers would get all crusty.So about 8 yrs ago replaced everything and flushed all the line with alcohol and filled it with dot 5 silicone, haven't had a lick of trouble since and I have one of the best pedals I've ever had........just saying.
     
  22. r7bis
    Joined: Mar 12, 2011
    Posts: 36

    r7bis
    Member

    not sure if anyone mentioned it (i glanced thru the comments) but the silicone has more of a spongy pedal feel to it because it compresses even tho its a liquid.
     
  23. Rotobo
    Joined: Dec 21, 2009
    Posts: 39

    Rotobo
    Member

    I agree with r7bis,, My silicone is coming out as we speak. It sucks.
     
  24. 1934coupe
    Joined: Feb 22, 2007
    Posts: 4,645

    1934coupe
    Member

    This is what I was told to do by a caliper rebuilder. I had gone the silicone route on a complete brake rebuild, calipers, SS lines sleeved master, cylenders etc. Could never get a pedal, turns out one of the bad things about silicone fluid is that it traps air bubbles in it. So I was told to flush it all out with alcohol. After a long thorough cleaning I replaced it with dot 3 and no problems. I did put silicon in my 65 Olds 15 years ago when I replaced everything but a few steel lines and have had NO problems.

    Pat
     
  25. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,025

    Mr48chev
    ALLIANCE MEMBER

    Yep, it is what you use to flush the lines going in either direction when changing brake fluid. I'd flush the system with the alcohol before taking it apart to make the changes.
     
  26. yblock292
    Joined: Oct 10, 2006
    Posts: 2,937

    yblock292
    Member

    all new brake systems i do i use dot 5 silicon fluid, older systems i'll flush with alcohol first then replace with dot 5.
     
  27. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,025

    Mr48chev
    ALLIANCE MEMBER

    Guys who don't tend to drive their cars much and especially the local Corvette owners really seem to like the Silicone brake fluid but if the cars don't sit all the time regular brake fluid isn't an issue and tends to work better in most cases. Each has it's pluses and minuses. Street rodders originally went for it because it didn't eat the paint like regular brake fluid and that was the main selling point for rodders in general.
     
  28. I also don't know why you would want to change to regular brake fluid. I have had silicone in a Corvette for about 15 years. It sat for 10 and the brakes were still good with no leaks and no rust and Vette brakes are prone to rust. I put it in my 34 truck's brakes because I see no drawbacks other than the cost.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.