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  • Shimano bleeding – what did I do wrong? 🙁
  • phil5556
    Full Member

    As per my other recent thread, I’ve just bled some Shimano 4 pot XT 8120s for the first time. Followed the Park Tools video to the letter (I think) and was expecting the levers to have that solid Shimano feel when I’d finished, that feel that I don’t really like preferring SRAM.

    But they don’t, they feel more like a nice SRAM lever now, which my wife won’t like! They both feel the same, which is at least something and they do seem to work well, just with more throw than I think they used to.

    It’s as if the pads haven’t advanced enough now I’ve finished. I used a bleed block that seemed to fit exactly, I presume it’s not supposed to be under sized to allow the pistons to advance slightly when bleeding?

    Only other thing I can imagine is that because the bleed port is on the bottom of the caliper there’s a bit of air stuck at the top? I could try re-bleeding with the calipers off and upside down?

    Fat-boy-fat
    Full Member

    Did you rotate the levers repeatedly to get the very last bit of air out? Normally a very simple procedure:

    1. Rotate lever to horizontal, unscrew reservoir top and fit shimano bleed pot full of fluid.

    2. Unscrew free stroke screw as far as it goes.

    3. Remove pads, push pistons back into caliper, fit bleed block to caliper.

    4. Open bleed port and caliper and let fluid run down until you can clearly see new fluid coming out of caliper.

    5. Close bleed port on caliper.

    6. Rotate lever down to normal position and flick lever quickly and repeatedly until no bubbles come out.

    7. Rotate lever up to horizontal and flick lever again until no bubbles come out in pot.

    8. Rotate lever up to about 30 degrees above horizontal and do the flick thing again.

    9. Keep rotating and flicking until you get no bubbles at all coming out.

    10. Remove bleed port but dribble a bit of fluid into the reservoir so that it is super full. Put the screw back into the reservoir. Screw the free stroke adjuster all the way in. Remove the bleed block from your caliper. Clean everything up and refit pads.

    11. A couple of pumps of the lever with your pads and wheel in, and you should be all good to go.

    oceanskipper
    Full Member

    You may find they get stiffer in use plus part of it is the ServoWave feature I think. Also I noticed on mine that the higher grade rotors are ever so slightly thicker so the levers stiffen earlier and as such feel a lot firmer, again probably due to the ServoWave.

    phil5556
    Full Member

    I could be mi-remembering what they felt like originally too as it’s not my bike 🤔

    I’ll get my wife to give them a pull.

    mashr
    Full Member

    Shimano’s always feel like that in the stand ime – take the bike on a ride and see if you/they feel the same then

    oceanskipper
    Full Member

    I’ll get my wife to give them a pull.

    After she’s tried the brakes obviously.

    benos
    Full Member

    Amen to rotating and flicking. I got the tip from a Kiwi (iirc) mechanic in a bleed vid which I can’t find now. Keep going until the bubbles stop – it takes a while!

    diggery
    Free Member

    benos – was it Marshy, and this vid?

    stick_man
    Full Member

    Flick the brake hose a well as the lever.

    PJay
    Free Member

    Did you bleed with the bite point adjustment screws wound out (then screw them in for less freestroke)?

    BearBack
    Free Member

    <p style=”text-align: left;”>If they’re not a solid feel on the stand, i’d say there’s air in there.</p>
    I’ve found 8120 and 9120 4-pots like to trap air in the caliper and a gravity “flush” absolutely won’t help you with that… unless you have the caliper in you hand and can have the bleed nipple above the caliper body, contorting into all manner of positions whilst tapping it furiously.

    benos
    Full Member

    @diggery that’s the one! I don’t go to his lengths but it was great for tips.

    @stick_man
    yeah, I flick the hoses too 🙂

    colp
    Full Member

    I let the caliper hang down, put the front wheel on a box, bleed funnel on. It can take hours to get every last bubble out.

    If there’s too much lever travel, try a pump or 2 on the brake with the wheel out and let a bit more fluid go into the master.

    phil5556
    Full Member

    Did you rotate the levers repeatedly to get the very last bit of air out?

    Yes I did it your way except I started by pushing fluid up from the caliper as per the Park Tools video.  I’ll try again with the caliper off and hold the bleed nipple at the top.

    Did you bleed with the bite point adjustment screws wound out (then screw them in for less freestroke)?

    Yes, maybe not enough though. 3 turns I think.

    If there’s too much lever travel, try a pump or 2 on the brake with the wheel out and let a bit more fluid go into the master.

    I’ve not had to do that since my base spec SRAM Levels.

    bigyan
    Free Member

    You want the bleed nipple to be the highest point on the caliper while bleeding, on quite a few calipers/frames/forks you will need to remove the caliper from the frame/fork to bleed.

    Adding to FBF lever rotation advice, I also point turn the bars and tilt the bike up and down in the stand to get air bubbles out the lever, imagine rolling an air bubble around the lid of the master cylinder, trying to get it to line up with the bleed cup fitting.

    whippetboy
    Free Member

    I had a similar problem after bleeding them the way shimano states having had no problems over the last few years. The solution was to do a gravity bleed, found a 20min ish vid on yt of a bike shop in the states with a bloke showing you how to do it (he had a dangley earring from memory). Using the same kit, did that and hey presto back to factory bleed quality although the rear took two attempts. I think it also included setting the brake to your pad wear as well. Hope that helps.

    chrismac
    Full Member

    Another vote for the gravity bleed technique here. Works every time as long as you remember to unscreened the freestone screw first.

    nparker
    Full Member

    I followed the instructions supplied with the epic bleed solutions kit and found these gave the best results out of all the different “how-to’s” I’ve tried in the past.

    dirkpitt74
    Full Member

    Top down bleed always seem to work better than bottom up for me.

    Have you done it with caliper on or off the bike?

    Take caliper off so you can get it & bleed port as low as possible.

    Have you done the ‘pull lever & crack open & close bleed port’ a few times too? That always seems to get a bit more aiirated fluid out.

    hijodeputa
    Free Member

    Yorkshire bike mechanics method is simple and has always worked for me

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