No rear brake???????

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This topic contains 24 replies, has 0 voices, and was last updated by  murph the surf 11 years, 4 months ago.

Viewing 13 posts - 16 through 28 (of 28 total)
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  • #249082

    Richard W
    Member

    Make sure the petal goes fully back as well.

    #249194

    i boiled mine on parachute hill too but i cooled it straight away with camelbak water (the caliper, not the disc) and it came good straight away.

    i reckon on yours the bubble has worked up to the master cylinder and has “airlocked” it.

    try taking the brake line off at the master cyl. end first Murph.
    pull the banjo bolt right out and stick your thumb over the hole and pump it.
    if you feel pressure on your thumb the seals are ok.
    pump it a few times and hold it down as you let the top of your thumb off a bit and air will come out.
    keep doing this until mo more air comes out.
    the rest of the system can be bled with a vacuum (syringe or pump or what ever or the ols skool “bottle and tube, pump and nip” way)

    when i rebuild my mates YZ we had heaps of trouble bleeding brakes up and this procedure is what the manual recommended, to pre bleed the master. (wish I’d read it first :( )

    worst case is you will know straight away if the master seals are blown but i will almost guarantee they will be fine mate. ;)

    there is very little air pressure generated in a boil situation, compared to the pressures the seals take during normal application.

    :huh: why am i telling a fitter this :laugh: :laugh: :laugh: :laugh:

    #249083

    Nickj has got it Murph.

    Take the calliper off and get it as low as you can, place something about the size of your disc between the pads.
    Make sure the tube on the bleed screw is tired on tight so no air can get in, place some brake fluid in a bottle and place the other end of the tube in this. Open your bleed screw up to start pumping the new fluid will come through and get the air out.

    Make sure the open end of your bleed hose always stays under the fluid in your bottle it can’t suck any air back in then.

    Hope this heaps.

    If all else fails just ride it without the back brake it didn’t seem to slow you down at all Sat Afternoon :laugh: :laugh:

    #249205

    Thanks you all. :)
    Played for a little while today on the braking of the 5 hungey.
    Tried everything that was thrown at me. :blink:
    No Bloody Good.
    Sorry, ya’ll.
    There must be that much of a bubble of air in the system that it can not be reach by any other means. :ohmy:
    I may break the system, tomorrow. :ohmy: 👿 :pinch:

    #249297

    Aint getting any noise/pressure release from the slave cylinder/bleed screw.
    No matter how many times ya pump da pedal.????????????/
    I’m over it. :sick: :silly: :blink:
    Catch up with ya’s when our worlds collide…..!!! :silly: :silly: :pinch: B) B)
    Cheers, Rock On.
    Murph

    #249095

    alan
    Member
    Buzz wrote:
    I have used syringes before with no success, so I splashed out and bought a vacuum pump designed to bleed brakes and it works a treat. I loaned it to Aaron to bleed a brake on a Kato 65 he was having trouble bleeding and it worked a treat again. I think it cost me about $90-00, but it payed for it self already by not having to pay my local mechanic to do it. Hope this helps.

    Buzz

    reckon buzz no s what he is talking about here murph B)

    #249198
    menace wrote:
    i boiled mine on parachute hill too but i cooled it straight away with camelbak water (the caliper, not the disc) and it came good straight away.

    i reckon on yours the bubble has worked up to the master cylinder and has “airlocked” it.

    try taking the brake line off at the master cyl. end first Murph.
    pull the banjo bolt right out and stick your thumb over the hole and pump it.
    if you feel pressure on your thumb the seals are ok.
    pump it a few times and hold it down as you let the top of your thumb off a bit and air will come out.
    keep doing this until mo more air comes out.
    the rest of the system can be bled with a vacuum (syringe or pump or what ever or the ols skool “bottle and tube, pump and nip” way)

    when i rebuild my mates YZ we had heaps of trouble bleeding brakes up and this procedure is what the manual recommended, to pre bleed the master. (wish I’d read it first :( )

    worst case is you will know straight away if the master seals are blown but i will almost guarantee they will be fine mate. ;)

    there is very little air pressure generated in a boil situation, compared to the pressures the seals take during normal application.

    :huh: why am i telling a fitter this :laugh: :laugh: :laugh: :laugh:

    I guess, the Old Bulls that I went past, down that bloody hill are laughing now.
    And so they should be. :blink:
    Laughing Sams Dice. :laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh:
    Thanks Menace?? “don’t ya want coco’ coco’ cocaine. :woohoo: :woohoo:
    Talkin about LOVE
    ZEP FEVER
    Let you know how it went tomorrow.
    Cheers
    Murph

    #249096
    Buzz wrote:
    I have used syringes before with no success, so I splashed out and bought a vacuum pump designed to bleed brakes and it works a treat. I loaned it to Aaron to bleed a brake on a Kato 65 he was having trouble bleeding and it worked a treat again. I think it cost me about $90-00, but it payed for it self already by not having to pay my local mechanic to do it. Hope this helps.

    Buzz

    Where did you buy this machine??????/vacuume pump thingy?????
    May be a last resort as I haven’t had any of my bikes back to the shop, well hardley ever????
    I did take this Fuel injected bike back to see if they could find a fault. They didn’t and luckily it never happened again???????????????????????????????????????????????????????????????????????????
    Cheers
    Murph
    P.S. Keen to have another go at Murphs Horn when ya iron out the wrinkles. :ohmy: :unsure: 😆 :cheer: :laugh: :laugh: :laugh: :laugh: :laugh:
    Nothing is impossible. :whistle: :whistle: :pinch:

    #249300

    Alex
    Member

    Murph if you brake and clutch bleed your cars and bikes yourself – sure get a vacuum bleeder they are brilliant. If it’s just to fix your back brake IMO bring it to a shop.

    #249301

    Ron Birrell
    Member
    Murph the surf wrote:
    Buzz wrote:
    I have used syringes before with no success, so I splashed out and bought a vacuum pump designed to bleed brakes and it works a treat. I loaned it to Aaron to bleed a brake on a Kato 65 he was having trouble bleeding and it worked a treat again. I think it cost me about $90-00, but it payed for it self already by not having to pay my local mechanic to do it. Hope this helps.

    Buzz

    Where did you buy this machine??????/vacuume pump thingy?????
    May be a last resort as I haven’t had any of my bikes back to the shop, well hardley ever????
    I did take this Fuel injected bike back to see if they could find a fault. They didn’t and luckily it never happened again???????????????????????????????????????????????????????????????????????????
    Cheers
    Murph
    P.S. Keen to have another go at Murphs Horn when ya iron out the wrinkles. :ohmy: :unsure: 😆 :cheer: :laugh: :laugh: :laugh: :laugh: :laugh:
    Nothing is impossible. :whistle: :whistle: :pinch:

    Hey murph, I bought it through gasweld tool centre here in Tamworth but you could get one through any reasonable tool shop.

    Buzz

    #249311

    Had another play with my rear brakes yesterday
    Pulled them completely apart, found a bit of sludge in the master cylinder.
    Question:- When operating the master cylinder with no fluid should it it suck air back through the top on the return stroke or is it meant to suck air from the reservoir?
    I would of thought it would return so far and then take in more fluid ready for the next pump.
    Cheers
    Murph

    #249084

    Adam Rodgers
    Member

    Murph,

    You would need to block the outlet with your finger to stop the air returning from where it came.

    When the system is assembled and full of oil the spring will push the piston back but can’t suck the calliper piston in as there is to much effort required. This allows it to act a bit like a one way valve.

    You’ll need to act like a valve :P

    Put some fluid in and cycle it past your finger as per Menace’s suggestion.

    Hope this helps :huh:

    Adam.

    #249837

    New master cylinder seal/piston kit
    It bled straight away and all is good. B)
    Cheers
    Murph

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