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Cleaning brake pistons? Dot fluid? Cotton bud?

pilsburypiepilsburypie Posts: 891
edited March 2009 in MTB workshop & tech
Gonna be changing my pads soon on my Juicy 5's. There seems to be lots of censored and pad dust inside the brake unit around the pistons. What is the best way to clean this as part of routine maintenance? Cotton bud and Dot fluid? is there a better way to get into the nooks and crannies?

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  • GrindyGrindy Posts: 25
    I would recommend getting some brake cleaner from a motorbike shop (or Halfords?) You could spray it on and around the caliper then use an old tooth brush to remove the stuck on dust and muck.
  • DOT fluid is nasty corrosive stuff that will atack any painted finishes. Keep it inside your brake calipers and not on the outside (although some disagree [sigh]). Meths and Isopropyl alcohol are suitable for cleaning DOT systems and are less aggressive than brake cleaner. The seals in the caliper will thank you.

    An old tooth brush may get you into most of the nooks and crannies, but cotton wool buds will get you access to the last of the grime.
  • supersonicsupersonic Posts: 82,708 Lives Here
    petercarm wrote:
    [sigh].

    Is that in reference to the other thread on this matter? The way you are going on you would think people had said to drop the whole caliper in a vat of the stuff!
  • dave_hilldave_hill Posts: 3,877
    Gonna be changing my pads soon on my Juicy 5's. There seems to be lots of censored and pad dust inside the brake unit around the pistons. What is the best way to clean this as part of routine maintenance? Cotton bud and Dot fluid? is there a better way to get into the nooks and crannies?

    Leave it. Do your brakes work? Can you see it when you're riding? That's all that matters, then.
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  • Can't remember if the pistons are stainless or resin - if they're resin they won't get corroded by muck & grime, stainless ones will eventually pit if you don't clean them.

    As far as DOT fluid goes, it is supposed to attack paint, but I've never seen it happen - I still wouldn't use it to clean stuff though. It doesn't seem to touch anodising.

    For cleaning calipers, I'd use washing powder! Really - if you can get a small toothbrush in, just dip it in hot water, then dip it in some powder, then scrub away - it seems to clean anything including salt encrusted motorbike stuff.

    Not a cheapskate though...
  • petercarm wrote:
    DOT fluid is nasty corrosive stuff.

    Agree. It can damage everything from anodizing to carbon fiver. It will make alloy oxidize and steel rust. It also leaves a residue so does. The longer it is exposed to air for the more corrosive it becomes so if you ever do get it on anything be positive to wash it of. More so you don't want it on your skin and really not in your eyes or swallowed. Its one of those things that in the long run can do you real damage.
  • stumpyjonstumpyjon Posts: 4,069
    I just clean mine from time to time with Hope censored shifter and a brush seems to get all the gunk out.

    DOT fluid will strip paint, I didn't believe it until I left an allen key covered in the stuff on top of my metal heater in the garage for half an hour and the paint bubbled. That said with all the fuss made I thought it would strip paint if it so much as touched it. It doesn't (at least not DOT 5.1) if you deactivate it with water and remove it reasonably quickly.

    Think DOT 4.1 is more corrosive.
    It's easier to ask for forgiveness than for permission.

    I've bought a new bike....ouch - result
    Can I buy a new bike?...No - no result
  • funny I thought that DOT 4.1 would be less corrosive than DOT 5.1
    4.1 apparently resists heat less well than 5.1
    that is probably if your doing major downhill though
    I assume this is French petrol - be careful in reverse - the car will retreat rapidly at the least provocation.
  • stumpyjonstumpyjon Posts: 4,069
    Yeah I assumed that but it appears Dot 5.1 has a higher boiling point and is less corrosive, double bubble :lol: .
    It's easier to ask for forgiveness than for permission.

    I've bought a new bike....ouch - result
    Can I buy a new bike?...No - no result
  • pilsburypiepilsburypie Posts: 891
    dave_hill wrote:

    Leave it. Do your brakes work? Can you see it when you're riding? That's all that matters, then.

    The lever return is a bit slow...... thought a clean around the piston may sort this - if not just be a good maintenance exercise....

    So I take it Dot fluid aint ideal.... may go for the isopropyl alcohol then....

    Cheers
  • nicklousenicklouse Posts: 81,520 Lives Here
    funny I thought that DOT 4.1 would be less corrosive than DOT 5.1
    4.1 apparently resists heat less well than 5.1
    that is probably if your doing major downhill though

    there is no fluid with a DOT4.1 spec it is DOT4.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • nicklousenicklouse Posts: 81,520 Lives Here
    dave_hill wrote:

    Leave it. Do your brakes work? Can you see it when you're riding? That's all that matters, then.

    The lever return is a bit slow...... thought a clean around the piston may sort this - if not just be a good maintenance exercise....

    So I take it Dot fluid aint ideal.... may go for the isopropyl alcohol then....

    Cheers

    maybe you need to clean the lever end?

    brake cleaner is great. if you then want to lude the seal then yes a bit if brake fluid is fine or even some brake rubber grease. just keep both away from the pads.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
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