Brakes Wheels 1st Gen Tires Soft pedal?

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by mrntd, Apr 3, 2014.

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  1. mrntd

    mrntd Well-Known Member
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    I replaced the fluid last year with ATE blue and bled them through. But the pedal still feels soft. The brakes work fine. It's just once I feel the brakes bite well there is still a good deal of movement left.

    My experience with air in the line is that once the pedal is down and you pump it it firms up. I don't have any of that. Most folks say they don't feel any difference with stainless line on the MINI.

    I'm looking for thoughts and ideas.

    Thanks
     
  2. DneprDave

    DneprDave Well-Known Member
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    I have no experience with ATE blue, but I have some with silicone brake fluid.

    Silicone bake fluid (DOT 5) is slightly compressible and causes a soft feel to the brake pedal. It shouldn't be used in ABS brake systems.

    Is ATE blue, DOT 5?
     
  3. Nathan

    Nathan Founder

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    ATE Blue is DOT 4

    It's the same as the fluid MINI/BMW uses but is colored Blue.
     
  4. ScottinBend

    ScottinBend Space Cowboy
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    With air in the lines it will never feel firm.
     
  5. Crashton

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    I didn't feel a difference when Chad put the SS brake lines on my MINI. I know they are better than the oem lines. Changing them out isn't going to solve this problem.

    Are your rear pads indexed into the piston correctly. I have seen that cause a similar problem.
     
  6. mrntd

    mrntd Well-Known Member
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    I'll check the rear pads. Then try bleeding the system again.
     
  7. tallguymini

    tallguymini New Member

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    Bleed all 4 again
     
  8. Dave.0

    Dave.0 Helix & RMW Powered
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    I use Motul RBF600 Synthetic DOT 4 Brake Fluid 500 ml and you can buy it on Amazon for $17.50.

    You need 3 for a complete flush.
     
  9. Crashton

    Crashton Club Coordinator

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    I'm going to switch my fluid out using Stop Tech STR-660. It has the same wet boiling point as the Motul, but its dry boiling point beats it.

    I've never used this before so I'll let you know how I like it, should I survive this experiment of using a non-Dave O approved product. :wink:
     
  10. cct1

    cct1 Well-Known Member
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    If there is air in the ABS, you'll need someone with the tool to get it out--either the stealer or an independent shop with a tool.

    The other possibility is a bad master cylinder. Turn the car on, and push hard on the pedal--what happens when you do this, with constant, firm pressure?

    Also, check your lines--if fluid is leaking out, air is leaking in.
     
  11. mrntd

    mrntd Well-Known Member
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    Update. I have upgraded the front to R56 calipers and stainless lines. I have bled the system 4 times.

    Cct1's question. When I push the pedal the breaks work but the pedal slowly keeps going down for a bit. But not all the way to the floor. It is not a firm pedal. It feels like rubber at the end of travel.

    I noticed when I was bleeding the rears a small stream of something dark came out in the bleeding line? This was not happening in the front. I thought it might be the rear lines themselves deteriorating.

    There are no leaks from anywhere and no loss of fluid.

    So what are everyone's thoughts?
     
  12. Crashton

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    I think you still have air in the system. Sinking peddle sort of sounds like a bad master, but I doubt that is it or rear brake lines failing. Not much help I know, but that's all I've got.

    Edit What fluid are you using? Is it from a new sealed container?
     
  13. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Has the fluid in the reservoir ever been below the "min" line when bleeding or changing fluid? If so, you probably have air in the ABS system. Because of where the reservoir outlet is located, the reservoir will never look completely empty, but it's still empty enough to get air in the lines.

    As for the dark color when bleeding the rears... Could be just old fluid in the calipers or lines.
     
  14. mrntd

    mrntd Well-Known Member
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    I should say that the sinking pedal only happens when the car is running.
     
  15. vetsvette

    vetsvette MINI Alliance Ambassador

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    Had the exact problem when I replaced my brake system. (rotors, pads, and stainless lines) I made the mistake of draining and refilling the old fashioned way by pumping all the fluid out and re-filling and bleeding. After that epic fail, I bought a pressure bleeder which I should have used to begin with, and re-bled multiple times. I, like you, had useable brakes, but a very soft pedal. Ended up taking it to my independent shop where he hooked it up to the Mini diagnostic computer and we bled it a few more times using his commercial pressure bleeder system and with the computer activating the ABS system before and after each wheel. That improved it considerably. It's still not a firm as I remember, but I've been messing with the darned thing so long that I could be mistaken. It's stopping just fine and at the extreme I can get the tires to chirp so I'm not worried about it from a safety point of view. After I put about 500 miles on it and have everything broken in I'm going to replace all the fluid again, but using the pressure bleeder this time.
     
  16. ZippyNH

    ZippyNH Well-Known Member

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    What kind of pads?
    Know that some pads, like akeebonoo pads, and feel kinds soft for a few miles...mine felt like I had air in the system, even after bedding them....but they firmed up after about 1000 miles...put them on with new high carbon rotors 3000 miles ago...the factory machining marks are still on the rotors the pads are so rotor friendly...lol.
     
  17. mrntd

    mrntd Well-Known Member
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    Went for a long drive today. After a considerably twisty and hilly part I had a really long pedal. It came back after an hour cool down. I think the fluid I used when changed the calipers was contaminated. I'm going to border some new fluid and power flush the system.
     
  18. Crashton

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    Never add fluid from an open container. Good way to have your fluid boil. You haven't lived until you are heading downhill in to a tight turn & you try to brake & all you have is bubbles for fluid. Big time yikes! Only happened to me once, but it is an experience I will never forget & hopefully never repeat.
     
  19. mrntd

    mrntd Well-Known Member
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    What is the tool? Is there another way to bleed the ABS?
     
  20. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Only things I'm aware of that can do this are autoenginuity (which I have, and have used successfully) and the dealer tool (which I also have, but haven't used). There may be other advanced scan tools with BMW extensions that can do it, but I don't know this to be fact.
     

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