Brake bleeding hassles

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  • #99736

    Roy
    Member

    I’ve just put a calliper cooler (heat sink thing) in my rear brake line and I’m having all sorts trying to bleed it. What does it mean when you press on the pedal and nothing at all happens. The pads don’t move in from their spread position at all.

    #199154

    I’m no expert what so ever on this but last time i did brakes i used a large syringe about 100mm and a small tube and pushed the fluid from the bleed nipple back up into the reservoir doing this a few times till the air bubbles stop making sure you do not put any air bubbles in as you go. Then lock it off and bobs your uncle

    #199160

    Roy
    Member

    That’s exactly what I’m doing Corey but it’s not working. It’s like somethings wrong but it was all fine before I started so I guess it has to be air in there somewhere.

    #199162

    I would guess a air block for sure. I HATE fixing brakes :angry:

    #199161

    alan
    Member
    Corey8 wrote:
    I’m no expert what so ever on this but last time i did brakes i used a large syringe about 100mm and a small tube and pushed the fluid from the bleed nipple back up into the reservoir doing this a few times till the air bubbles stop making sure you do not put any air bubbles in as you go. Then lock it off and bobs your uncle

    thats what i have found to sorry not much help :blush:

    #199163

    pete
    Member

    I had some crap blocking the nipple which caused me a head ache. :pinch:

    #199165

    drew
    Member

    bundy, try finding a bit of tube that will fit onto the bleed nipple, a nice fit so it seals.

    get a bit long enough to touch the floor, get a jar put enough brake fluid in the jar to cover the end of the tube, crack the bleeder then pump the lever.

    keep an eye on the reservoir and top it up as it goes down. do this until the air stops coming out the tube in the jar.

    doing it this way you don’t have to hold the lever down while you tighten the bleeder back up, as when you let the lever back up it will only draw fluid back in.

    if using this method does not help any, there may be a leak in the joins on the cooler somewhere.

    #199167

    Roy
    Member

    Thanks for the tips. I took the cooler back out and re-bled it and all is fine. Will get me through this weekend and then when I have a bit more patience/time will try again. Must be air getting trapped in the extra long banjo bolt somehow.

    This was what I am trying to fit.

    http://slavensracing.com/products/brakes/brake-caliper-cooler-ktm-husaberg

    It had better make my brakes work better when I finally get it on as it makes bleeding brakes a real prick.

    #199156

    Roy
    Member

    Been thinking about your technique x-y. Wouldn’t it be better if you put brake fluid in the tube and then tied the tube to something high. This way the fluid is always down against the nipple and the air bubbles will rise away from the nipple. Just a thought. I think I will give this a go next week on attempt 6 of trying to get this cooler fitted.

    #199157

    David
    Member

    Hello Bundyroy,
    Thought i would throw in my 2 cents worth.
    One thing i would suggest is that you back off the push rod adjuster on the brake pedal.
    You may need a longer stroke to push more fluid through.
    Sometimes when the adjustment is used to take up pad wear you actually reduce the piston stroke in the master cylinder and in doing this you reduce the amount of fluid that you get through.
    I have used the brake fluid in the bottle process and it works. The reason behind the tube being submerged in fluid is to stop the bleed nipple drawing air back in as you lift the pedal. If it is not in the fluid the air in the caliper just gets drawn in and out and nothing is achieved.
    I am always a little wary of forcing fluid through a master cylinder in reverse. The seals in the master cylinder are cup seals and are meant to work in one direction. Forcing fluid over the cup seal lip in reverse can cause damage to the seal.
    As everyone has said keep an eye on the reservoir as they are pretty small on the KTMs.
    I have been thinking about using the extended reservoir on my KTM to aid in fluid cooling.

    As i said just my 2 cents worth.

    Rebore.

    #199173

    Roy
    Member

    Thanks Rebore.

    I have put the reservoir extender on as well as the cooler. I had to take the cooler off at this stage to get it working in the timeframe I had left before riding. Hopefully the extender by itself will still make a difference.

    There is no worse feeling then cruising down a long steep hill and going for the rear brakes only to find nothing let me tell you. Front brakes alone are okay but only if you know that is all you’ve got and ride accordingly.

    #199158

    Chris
    Member

    Recently put braided brake lines on me DRZ400 and it took forever to bleed.. After finally getting it done and chatting with TB he suggested next time to fill the brake reservoir about 1/2 way.. Get a fat long syringe and fill it with brake fluid, then a small hose(1/4′ works well) which one end will go on the end of the syringe and the other end over the bleed nipple which is in the open position… Then pump the fluid backwards though the lines, caliper etc until fluid bubbles into the reservoir.. It may cause spillage and a bit of a mess at the reservoir.. However all air will not only be gone but all fluid in place… Ceanup with brake cleaner..

    for what its worth…

    #199174

    jamie
    Member

    *Put a new master cylinder on my husky,had a nissan, then replaced it with a Brembo which was slightly different lengths. Didn’t have a longer hose handy the only hose lying around was from busted camel back. No probs – same diameter,but on bleeding found an air pocket which was now clearly visible,prior to the master cylinder. I removed the reservior while bleeding and got the air to rise back.

    *dodgey backyard mechanic :laugh:

    #199175

    David
    Member

    Yep totally agree!
    I lost my rears at Micks Birthday ride and on the wet clay trails the front brakes were no fun.
    That’s why i am thinking about using the reservoir extension.

    Also had another thought, in my dark old mechanic days we used to leave problem brake bleeds to sit over night and bleed them in the morning. Sometimes used to get a good result, i guess the theory is that the air would settle????

    #199177

    Roy
    Member

    did the leave overnight thing previously. I even took the calliper off the bike and sat it on the ground so it was all up hill to the master cylinder. I thought it was leave it so the air bubbles had time to work their way up the brake line.

    Why is it there never seems to be just a 5 minute job with bikes. Maybe I have problems cause I’m not drinking beer whilst working.

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