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Replacement lever question

JW599JW599 Posts: 30
edited February 2018 in MTB workshop & tech
I somehow managed to mess up the bleed port, took out the screw to find the thread from the port had broke and stayed attached to the port screw.

I've sourced a replacement lever assembly (M615), when this arrives will the entire system need a full bleed or could I get away with just topping up the oil from lever?



  • JBAJBA Posts: 2,716
    You'd struggle to simply top up the oil in the lever and get all the air out. Do a full bleed. It only takes 10 minutes and saves a lot of potential hassle.
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  • swod1swod1 Posts: 1,639
    you could burp the system maybe but a full bleed would be better. i have in the past used the burp method but changing levers your bound to get a load more air in the fluid.
  • JW599JW599 Posts: 30
    Full bleed it is then, many thanks!
  • JW599JW599 Posts: 30
    I think I did something wrong!

    The bike hasn't been out for about a week and some oil has escaped. Enough to lose a good amount of bite from the lever.

    It seems to be coming from where the brake hose enters the brake lever assembly. I didn't find any oil around the bleed screw.

    How tight should the connecting bolt be? Could it be because I over-tightened and damaged the olive or didn't tighten enough?

    Not yet had a chance to remove the connecting bolt to have a proper look.
  • cooldadcooldad Posts: 32,601
    Most likely not enough, if it's all assembled correctly. Nip it up and see.
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  • JW599JW599 Posts: 30
    Let hope this sorts it.

    I could literally un-screw it by hand.
  • The RookieThe Rookie Posts: 27,748
    That's not going to hold the pressure generated when braking.

    Why did you not do it up first time?
  • 02GF7402GF74 Posts: 1,294
    JW599 wrote:
    Let hope this sorts it.

    I could literally un-screw it by hand.

    That's much too loose.

    Generally the olive should be replaced but as you are replacing like for like, you will probably get away with it.

    The olives are brass or aluminium and are crushed in order to make the seal, same principle as in domestic plumbing.

    I think it is 7mm spanner you need, tighten it up, hard to explain how much but I would guess as much as you can when using your little finger on the end of the spanner., assuming you are not Arnold Schwarzenegger.
  • JW599JW599 Posts: 30
    All good since!

    I have no idea how that happened, I did use a 7mm originally but must have been in fear of overtightening after wrecking the bleed port - or bad karma hit me after shouting at a motorist.

    Anyway, the other brake has been absolutely fine and was fitted weeks ago when I upgraded.
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