1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Dot 5

Discussion in 'Suspension, Steering & Brakes' started by giuseppe, Apr 19, 2017.

  1. giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    Is there a way of flushing the system before using DOT 5, replacing rear brake callipers at the moment, so thought it might be good idea to replace it with non absorbent brake fluid.
     
  2. hotrodder

    hotrodder Senior Member

    Messages:
    880
    Likes Received:
    9
    Your Mercedes:
    '93 320te, '54 ragtop beetle (in bits)
    stwat likes this.
  3. OP
    giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    thanks for information, having read through it, i think they talking a load of twaddle, having read through other literature there are pro's and cons, pro's are, you only need to do it once, does not absorb water, so does not rust, does not damage paint, does to damage seals. Cons, it is expensive, but considering you only buy it once every ten years or so, sound cheap,

    There can be sponginess, but only if not bled properly, and the system has to be flushed properly so as not be contaminated with other brake fluid which does not mix at all, can be messy, all this information I am quoting from another source who has more extensive knowledge of the product than i have. giuseppe
     
  4. hotrodder

    hotrodder Senior Member

    Messages:
    880
    Likes Received:
    9
    Your Mercedes:
    '93 320te, '54 ragtop beetle (in bits)
    Fair enough your car... i'd google 'abs brakes silicone dot 5' and price an ABS pump before you buy any of that nasty silicone brake fluid though [/tongue in cheek]
     
    stwat likes this.
  5. OP
    giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    Its a good job that I do not have ABS brakes, brakes changed from W210 to W211
     
  6. chardF

    chardF Senior Member

    Messages:
    369
    Likes Received:
    2
    Location:
    Warwickshire
    Your Mercedes:
    SL 1994 320 R129

    Unusual.
     
  7. OP
    giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    It changed from BAS in 2001 W210 to ABS in 2002 W211
     
  8. chardF

    chardF Senior Member

    Messages:
    369
    Likes Received:
    2
    Location:
    Warwickshire
    Your Mercedes:
    SL 1994 320 R129
  9. hotrodder

    hotrodder Senior Member

    Messages:
    880
    Likes Received:
    9
    Your Mercedes:
    '93 320te, '54 ragtop beetle (in bits)
    Dunno much about the specifics of BAS but isn't it essentially an 'evolution' of ABS or an extra add on to it?
    ABS uses a pump and valve block to 'control' brake line pressure using feedback from wheel speed sensors. BAS uses a pump and valve block to do the same(?) but works at waaaaaay higher pressure adding an accumlator to 'store' fluid at very high (hundreds of bar) pressure. This allows it to significantly and virtually instantaneously boost braking force in an emergency, the assumption being that virtually no one brakes 'properly' in a panic situation, and also can be used for convenience type stuff like brake hold?

    Viscosity is a big deal for the tiny orrifices and valves in ABS pumps. I'd wager it's at least as much of a deal with BAS pumps? Silicone fluids have higher viscosities than traditional brake fluids. When ABS started to appear brake fluid developments/changes went in a slightly different direction with lower viscosities being one of the deals... DOT 5 junk through a spanner in the works of the numbering system so we got 5.1 for a higher boiling point but today pretty much every road car uses DOT4 +, DOT4 super or some other variation of DOT 4 instead which are lower viscosity and usually still match or exceed the boiling points of both DOT5 silicone tat and DOT5.1 with lower viscosity and a narrow viscosity range

    Silicone fluid is also waaaaaay more prone to cavitation which is a bigger deal with ABS and modern variations on it/talentless driver aides. Silicone fluids aren't miscible with water so any moisture that gets in (the system is vented at the m/cyl and anyone that's poured silicone oils will have seen them entrain air) will stay seperate where it can 1) wreck just as much havoc as ancient glycol based stuff that's saturated with water and 2) have a bigger impact on brake fluid fade

    Back when silicone brake fluids first appeared they offerred higher boiling points than glycol based stuff which is no longer the case. Best case scenario IMO is that they're like cross drilled discs i.e. pointless these days. Personally i consider dot5 more like 'waterless coolants'... pretty much snake oil and definately a solution to a problem that doesn't exist unless the car or whatever is parked in a museum or garage 99.9% of the time and occasionally started and moved/driven gently to a show etc
     
    chardF likes this.
  10. OP
    giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    apparently not, I could be wrong, some one on here should know. ????
     
  11. OP
    giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    I think BAS was developed before ABS, but as before, I could be wrong
     
  12. chardF

    chardF Senior Member

    Messages:
    369
    Likes Received:
    2
    Location:
    Warwickshire
    Your Mercedes:
    SL 1994 320 R129
    ABS was developed in the 1950s, introduced in the 1970s, MB adopted it in 1978.

    Mercedes introduced BAS on the S Class in 96, standard equipment in 98.

    Dot 4 brake fluid is pretty cheap and easy to replace. What do MB reccomend, do you feel lucky?
     
    giuseppe and hotrodder like this.
  13. hotrodder

    hotrodder Senior Member

    Messages:
    880
    Likes Received:
    9
    Your Mercedes:
    '93 320te, '54 ragtop beetle (in bits)
    chardF likes this.
  14. OP
    giuseppe

    giuseppe Senior Member

    Messages:
    635
    Likes Received:
    1
    Location:
    Bournemouth
    Your Mercedes:
    E220Cdi avantgaurde 2001
    On my filler cap it reads DOT 4 plus, and reading the spec it does have a higher boiling point, have ordered a litre of Pentosin on amazon for £12, and no, I do not feel lucky, not a lot of outlets seem to sell DOT4 plus
     
  15. John Laidlaw

    John Laidlaw Senior Member

    Messages:
    5,224
    Likes Received:
    103
    Location:
    Wirral
    Your Mercedes:
    W212 E63 AMG V8 Biturbo
    That's a really good price!
     

Share This Page