Viewing 13 posts - 1 through 13 (of 13 total)
  • Can't get my new calipers to bled
  • PJay
    Free Member

    I’ve just fitted some M595 calipers in place of my old M585s, according to Shimano they’re compatible with the M585 levers. I just can’t get them bled (I’ve bled brakes before) the levers just don’t stiffen up. The only difference is that I’m using Stendec mineral oil rather than Shimano (I’ve got some Shimano on order in case that’s the problem).

    It’s a top down bleed, what am I doing wrong?

    Mister-P
    Free Member

    Have you used new olives? Tightened the bolts enough? Got callipers as low as possible to ensure no bubble in the top of the calliper?

    DezB
    Free Member

    Sounds frustrating! As far as I know all Shimanos are compatible, so wouldn’t have thought that was the problem.
    Tried binding the levers to the bars overnight? Worked on my brother’s Deores that were being a pain to bleed. (I mixed Shimano mineral oil with Citreon stuff from Halfords and they were fine)

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    younggeoff
    Full Member

    I reverse bleed shimano brakes.

    with the bike level and the caliper below the lever, take reservoir cap off.
    Use a syringe with a small tube on, attach to bleed nipple.
    open bleed nipple and draw all old fluid out with syringe.
    take another syringe full of fresh fluid
    attach to bleed nipple
    open bleed nipple and slowly force fluid back up thru the system until you have filled the reservoir.
    Close bleed nipple, put cap back on and job done.
    Seems to work for me.

    PJay
    Free Member

    Yep, new olives and inserts on the caliper ends, shroud nuts done up nice and tight. (I didn’t disconnect the hose at the lever ends). Did what I did before with the old calipers. The front lever has stiffened up a bit but it seems to stiffen nearer to the bar that the old M585s, maybe that one’s okay. I can’t get the rear to stiffen at all. I’ll have another go tomorrow when I’m a touch calmer, I was in a bit of a rush. I might try Shimano oil again although I’ve heard of people running them on oliver oil, so I can’t imagine that’s the problem. I might try the bottom up approach too.

    The stendec oil comes in a bottle without a dropper and I’ve also discovered that a syringe isn’t the best way to fill the resevoir either, what a mess!

    I’ll give it another go tomorrow, failing that it’s off to the bike shop.

    Mister-P
    Free Member

    You are bleeding these on the bike I assume?

    Rorschach
    Free Member

    Bleeding shimano caliper fron dry is always a royal pain in the arse.Bottom up first…then bleed them with the pistons protruding 4-5mm.Then do it again.They actually redesigned the calipers to make them a bit easier on xt-xtr.

    Northwind
    Full Member

    Yup, it’s just like trying to do motorbike brakes from dry without bench bleeding the master cylinder first- the lever piston is empty so can’t push anything through the system, but the piston isn’t filling because there’s nothing drawing it through. Sometimes it works, sometimes it doesn’t. Bleed from the bottom up, it’s always the best way with Shimano.

    bigyinn
    Free Member

    Did this 2 months ago, following caliper replacement to an M595.
    Do it from the caliper up to the lever, then from lever to caliper, allowing the pistons to move in an out a few times (use the bleeding block once the pistons start moving) and you should be fine.
    Any oil as long as its mineral oil. Castrol LHM FTW.

    PJay
    Free Member

    I think that the front’s probably okay although it’ll need a ride to be sure. The seals in the M585 were terribly temperature sensitive (hence the change) and, depending on the ambient temperature, lever travel varied greatly, so I’m not 100% sure what’s normal. I can pull the lever to within about an inch of the bar if I pull hard but it firms up pretty soon into its travel (there’s a diagram in the bleed instructions showing lever position but it’s unclear whether the ‘firm’ position is where the lever meets resistance or its furthest possible point of travel). The rear lever though goes right back to the bar though but there’s much more hose to get air into.

    — edit —

    I’m bleeding them on the bike but tomorrow I’ll try it with the calipers fixed to the adapters rather than loose. The instructions show the calipers loose to give a straighter hose but I’ve discovered (rather messily) that having a hand on the lever and another on the spanner controling the bleed value whilst trying to keep the resevoir topped up and control a loose caliper isn’t going to happen with just two hands!

    Being a fairly inexperienced home mechanic I tend to lose confidence and assume it’s something I’ve done wrong, but I’ll give it another go tomorrow, I guess I’ll get there eventually.

    PJay
    Free Member

    Okay, it sounds like a bottom up approach might be worth a try. What I don’t understand though is that if I follow the instructions for a top down bleed of a drained system to the point where I’ve got bubble free oil coming out of the bleed nipple with it open, and no bubbles rising from the resevoir port with the bleed nipple closed, how can the lever go straight to the bar with no resistance? One option might be a leak, but I’d have thought that I’d have noticed that (and it’s a new caliper) and I’d still have expected some resistance from the lever, unless the oil was gushing out but there’s no associated drop in fluid level from the resevoir anyway. The only other option I can see is a sizable pocket of air still in the system but the bleed instructions seem to suggest that no bubbles = no air.

    I guess it’s knocked my confidence a bit, I was intending to add hydraulic brakes to a bike I’m building for my partner but now I’m doubting my ability to bleed them safely.

    coatesy
    Free Member

    Still got air in there, usually a waste of time following the instructions that you’ve just mentioned as you end up with a lever that comes back to the bar.Either try the pull lever,open nipple,close nipple,release lever and repeat method, or use the syringe method mentioned.

    PJay
    Free Member

    Will do, thanks.

    — Edit —
    Embarassingly I recommended the open nipple, pull lever, close nipple, release lever approach to someone on here recently with bleeding difficulties, then I decided that I ought to follow the ‘official’ Shimano approach due to my inexperience. This approach actually instructs you to simply operate the lever with the bleed nipple open; that’ll learn me!

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