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Don't laugh (well, you can if you like) - it's the first time I've ever tried to bleed Shimano brakes 🙁 .
They are Deore M615s and I was using the Epic Bleed Solutions kit and [url= http://www.epicbleedsolutions.com/blog/how-to-bleed-new-shimano-brakes/ ]guide[/url].
Everything was going swimmingly until step 11: "[i]With the brake lever depressed, open and close the bleed nipple in rapid succession (for approximately 0.5 seconds each time) to release any air bubbles which may still remain in the caliper.[/i]"
I now realise I should have just fastened the lever to the bar with an elastic band or something, but what I actually did was get my girlfriend to squeeze the lever firmly while I undid the bleed nipple.
The lever shot back to the bar, and lost all resistance. The lever now seems to have become uncoupled from the rocker it actuates (which is just visible between the lever blade and the body of the lever), and when I move this rocker myself with my finger, it just clicks back and forth, offering no resistance and clearly not moving any hydraulic fluid around.
Having the caliper bleed nipple done up or undone makes no difference. I also tried pumping in more hydraulic fluid from the caliper bleed nipple, but nothing will enter the brake any more - pushing the syringe as hard as I dare, eventually fluid just begins to leak from around the tube where it should enter the bleed nipple.
I'm guessing I've ruined it, but what's gone wrong? I'd have thought if I'd blown a seal in the lever, I'd still be able to add more fluid..? There's also no visible signs of leakage anywhere.
Is the bleed screw out at the lever end when pushing oil back in?
Don't know. Sounds like her fault though. Get her to buy you some new ones.
Sounds like she has massively strong hands, count your chickens
Ha ha. She is a climber 😆
Yes, the bleed screw at the lever is still out at the lever end, and I've had a bleed block in place throughout. Any ideas from the morning crowd?
maybe an air lock somewhere, try a top down bleed, Epic syringe on the lever, fill it up, open bleed port at caliper and try and squeeze fluid through. Once/if you get bubble free fluid coming through into the tube/bag at the caliper you can then redo the final stages (on your own 🙂 )
Piston jammed in the master cylinder? You could try removing the lever and pulling the piston out using some pliers; bleed nipple and reservoir cap screw undone, of course.
I'd say try again, but in the spirit of conflicting advice I'd bleed from the calliper up to lever. If the lever is full of air it'll mean your only pushing it a short way rather than through the whole system
Piston jammed in the master cylinder? You could try removing the lever and pulling the piston out using some pliers
Thanks, that sounds possible. How does one remove the lever? Is it a case of just undoing the reach adjust screw fully?
After I've tried that I'll have another go at bleeding - either top down or bottom up 😕 😆
Agree with MArtynS, bottom up bleed is far easier...air rises so filling from the bottom will aid any air removal.
Sticka syringe in the lever with a small amount of fluid in it, attach a full syringe to the caliper. Depress plunger on the caliper syringe and the fluid should fill the caliper and hose and then fill the top syringe when the system is full.
I'd then depress the top syringe a bit and then repeat the bottom syringe. Then I'd depress the top syringe a bit more (not fully) then I'd pull the top syringe so it draws fluid up through the system.
The air should be gone (it should be almost all gone with the first depress of the bottom plunger). Remove the top syringe and put the bleed nipple back in. Then undo the bottom syringe and replace bleed nipple...it should then be fixed.
Total time is about 5 minutes per brake and it should be pretty clean and mess-free.
Sticka syringe in the lever with a small amount of fluid in it, attach a full syringe to the caliper. Depress plunger on the caliper syringe and the fluid should fill the caliper and hose and then fill the top syringe when the system is full.
This was the first thing I tried last night, but as per my first post at this point it's simply impossible to get any fluid into the caliper. Perhaps it'll become possible if I'm able to free up the piston in the lever...?
How does one remove the lever?
By undoing set screw 7 you should be able to take out the hinge pin (5)
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Aha, thanks! I just found this guide too which seems like it might be useful: https://www.bikehub.co.za/forum/topic/155987-fixworkaround-shimano-xt-m785-brake-lever/
Agree with otsdr. If fluid won't go through with both bleed points open, it's pretty much got to be that the master cylinder piston is "in" i.e. past the point at which it shuts off the reservoir and it sounds like it's somehow got jammed in there.
'Girlfriend' definitely not included in the kit Epic sent me. I'm going to give them a call to see why not. Disappointed.
what I actually did was get my girlfriend to squeeze the lever firmly while I undid the bleed nipple.
Cooooooorrrrr that does sound dorty... 😀
Now I realized there's nothing you can pull on, the connecting rod is not affixed to the piston.
Well, after all that, I don't think I can blame my girlfriend (or me, really).
I ended up draining the brake and taking the lever apart, and it's a terminally sticky master cylinder piston. It turns out you can't remove the lever blade on Deore M615 brakes to access the piston and try and clean it (bolt 7 on the exploded diagram above is only present on SLX and above), so the lever is a write-off.
I've posted a wanted ad for a replacement right-hand lever [url= http://singletrackmag.com/forum/topic/wtd-shimano-ispec-b-disc-brake-lever-or-complete-brake?replies=1#post-8629212 ]here[/url] if anyone has anything.