Results 1 to 5 of 5
  1. #1
    Curmudgeon
    Reputation: shif's Avatar
    Join Date
    May 2008
    Posts
    86

    Formula The One pad change question

    I just cleaned my pistons per the comments in a thread down below titled, “sticky pistons…” Great instructions in that thread, thanks guys. I re-mounted my calipers so that my rotors were perfectly centered in the slots and I installed new Kool-Stop pads. Very tight to fit them in, even though I retracted both pistons fully using a chunk of hardwood. Gave them both a good squeeze and everything seems centered nicely. Minor disc rub, actually very subtle, no big deal.

    Went out for a big ride and all seems good except the bite point is much further away from the grips than I’ve become accustom to. Is this normal? If not, how can I get the lever feel to be like it was back when the brakes were brand new, you know, lots of pre-travel in the levers. Were the stock pads thinner by any chance?

    By the way, the Kool-Stop pads seem to be good, at least in my riding environment, steep long descents in dry Nor Cal. I’m testing two compounds, sintered in the front and organic in the rear. A set of new pads measured together are .310 inch thick. I also received four sets of semi metallic + graphite pads made by DiscoBrakes (cheap via eBay), a set measure .320 inch thick. These might be difficult to install unless I can retract both pistons further.

    -Shif
    __________________________
    Ibis Mojo + TALAS 36

  2. #2
    Custom User Title
    Reputation: coldsteele's Avatar
    Join Date
    Jul 2004
    Posts
    1,287
    Per the instructions you need to open the bleed on the "lever" and let the fluid out so you don't tear the bladder in the "pump" on the lever. If you force the pistons back into the bore with the bleed port closed you could cause damage to you master cylinder/pump/lever.
    Team MOJO Wheels.

  3. #3
    mtbr member
    Reputation:
    Join Date
    May 2007
    Posts
    3,980
    If you do open the bleed port to do as stated above, you should attach a bleed syringe and make sure the bleed port is vertical. It's way cleaner this way. You may need a 2nd person to pull back on the plunger of the syringe to create a bit of a vacuum.

    If you dont have a bleed syringe, just wrap the lever with a rag and clean up with alcohol (99% if you have it).
    Lead by my Lefty............... right down the trail, no brakes.

  4. #4
    Curmudgeon
    Reputation: shif's Avatar
    Join Date
    May 2008
    Posts
    86
    Quote Originally Posted by coldsteele
    Per the instructions you need to open the bleed on the "lever" and let the fluid out so you don't tear the bladder in the "pump" on the lever. If you force the pistons back into the bore with the bleed port closed you could cause damage to you master cylinder/pump/lever.
    I have not seen the above statement in either the forum threads nor in the Formula The One owners manual. In fact the manual states that after cleaning the pistons you should:

    -Temporarily put the WORN pads back in position and, using a screwdriver to push down between the pads, push the pistons fully back inside the caliper.
    - Remove the worn pads.
    - Insert the new pads with the spring.

    Perhaps I don't understand how an open system works. In a closed system such as my trusty Hope C2 brakes, it makes perfect sense that reduced fluid volume results in more pad clearance.

    Well I guess I should bleed 'em at the levers now and see what happens.


    Please advise...

    -S

  5. #5
    Custom User Title
    Reputation: coldsteele's Avatar
    Join Date
    Jul 2004
    Posts
    1,287
    My bad I guess it was a phone conversation I had with Chris at Formula. Here is an email he sent me about bleeding. Maybe this will help.

    It is critical during the bleed process that the bleed port for the MC assembly is pointed vertical, otherwise there will be the potential for lots of air to get trapped in the reservoir. The port needs to be the high point of the reservoir so that air floats to the port and not to a location in the reservoir where it would otherwise get stuck and not come out.


    Regarding moving fluid into the system to check for bubbles: This is not a good way to check. When you force fluid into the system this way, you are actuating the rubber diaphragm in the reservoir as opposed to compressing air bubbles. If you have a bad bleed...it may be doing both. The best way to check for bubbles is to ride the brake after you bled it and then remove the MC from the bar, and situate it with the lever pointing vertical. (The bleed port pointing up.) Remove the bleed port and if you got a good bleed on it, you should see fluid all the way up to the top. If you don't, use a single partially filled syringe to suck the air bubble out and replace it with fluid. When you do this it is particularly important that the piece of tubing connecting the bleeder fitting to the tip of the syringe is nice and short (about an inch).

    Good luck. Call or email Chris. He is very quick to respond and is very helpfull.
    Team MOJO Wheels.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •