Hi all, i need some bleedin disk help.
New Shimano M785 disk brakes, shortened hoses but needing bleeding. When i go to do this it takes super human efforts to pass any fluid from the syringe to the lever. Also, when dripping back from the lever to the calliper nothing happens.
If i pull the lever fluid comes through though.
At one point fluid was seeking out (when pulling the lever) from beneath the long top cap on the brake lever. I took this apart, blew on it a bit, put it back on and then it seemed to stop??
My best guess is that there's something very small stuck in there somewhere, yet it still kinda works as it is but i know it's not 100% bled right.
On a side note, i can bleed a set of Avid Elixirs very easily, zero effort required to feed fluid through the hose.
Any suggestions?
The stopper is not in the yellow funnel is it?
Nope, no stopper anywhere. I only use that when i remove the funnel from the lever.
Bite point adjuster screwed too far in?
I struggled when bleeding mine, using 2 syringes that come with the Epic kit. I found that when pushing fluid from the caliper up to the lever, the pressure required to actually push the lever syringes plunger up was too much for the seals in the lever, resulting in fluid seeping out of the lever reservoir.
I got round that by just taking the lever syringe's plunger out when doing that stage.
This mimics what you would do with a Shimano bleed kit and its funnel.
Yes i have the same pressure issue. I'm using the funnel and syringe method. Have tried different twists on the funnel (not to tight and tighter) but make no difference.
Not tried it with no funnel though, so can see if that makes a difference. The issue though is that the funnel does not drip back to the calliper, so there must be more to it?
Have you got the wheel out and a bleed block in place?
Yep like francisco... above on Deore 596's I found the same thing as that. Although one brake did leak a bit, the other one didn't.
Force required was quite high with the Epic bleed solutions kit but I found lubricating the plunger of the lever end syringe with mineral fluid seemed to help.
Couldn't get a good bleed adhering to the Shimano method and funnel but the Epic kit worked a treat - all be it with a bit of fluid leaking from the lever seals.
Edit - good question dmort !
Yes, bleed block in place:
1. Remove wheel + pads. Add Yellow bleed block
2. Level lever, pop lever port screw and apply funnel with 2cm of fluid into lever port
3. Prepared syringe with genuine Shimano Mineral oil (lubed plunger with mineral oil) attached to calliper bleed port (just above 7mm spanner).
4. Plunger removed from Funnel, open calliper port (spanner) push on syringe to feed to funnel.
No fluid moves up, or with the mother of all effort it does in a non smooth hand hurting way.
5. Working in reverse, nothing drips out from the line when letting the funnel bleed to the calliper.
However if i squeeze the lever the fluid will come out at the calliper end.
Managed to pull back on the syringe to draw air through from the line (whilst the funnel is attached and filled with oil). This was again very hard to do but it did pull out some air.
so yeah, all the suggestions and silly things to miss along the way are covered (i think). I've tried it with the servo wave and lever adjust at different settings, still no joy.
Still need help!!!
You are opening the bleed nipple on the caliper enough aren't you (half a turn should be enough)?
Sure your not just incopetent 🙂
After all the things you have tried I personally would have taken it to a bike shop and asked for help.
The sun is shining, you need to be riding not bleading.
I'll try opening it a good half or more turn and see what happens. I've been doing it a bit over 1/4 turn so far, based on the spanner turning 90 degrees. Fingers crossed it's that simple!
Been following those instructions, hence trying to open over 1/8 of a turn as shimano state. Not tried a full 1/2 turn though.
Shop is a last resort, be great if i had somewhere really good to take it to. But even then they need it booking in so i won't get it done anytime soon enough to get out this weekend.
Also - I really want to be able to do this myself. I can do everything else and even sorted out the tricky Avid bleed system. There must be a way. Currently thinking about fitting new goodridge hose kit to ensure there's no blockage.
Bite point adjuster as previously suggested??
binno - it does sound like you have covered it all and if you can do Avids then competent 😉
I usually open the bleed nipple 1/4 to 1/2 turn as when fitting the syringe hose over it I always move it - towards the closed position for some reason !
Maybe try removing the bleed nipple completely and check for blockage ?
I've had this recently.
Whilst I'd bled the first 5 of the 6 M785s I have without any issue, the 6th one refused to bleed. 😕
[b]The solution is to slacken-off the bite point adjuster.[/b]
When it's screwed in fully, it appears to push the piston far enough forward to isolate the master cylinder from its reservoir and this prevents bleeding in either direction.
A bit of a design flaw if you ask me, but only a minor inconvenience once you know about it.
Just to be sure, Is the bite point adjuster the servo wave thingy?
thanks all for you help, if nothing more it's confirmed that I'm on the right track.
no, it's the small screw on the reservoir body, right next to the pivot around which the lever operates.
[edit] It's actually labelled as "free stroke" next to the screw [/edit]
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"•Easy-bleed System" according to Shimano.
http://singletrackworld.com/forum/topic/advice-on-bike-tools-for-workshop
must be a different binno.
That's still me, only one binno i know of?
Yeah, i was calling free stroke servo wave earlier. Had a go with that already. Bugger.
Going to try a fresh hose and see if it's blocked. I'll dismantle it and work it out one way or another.
When I did mine I'm pretty sure I opened the bleed nipple more than 1/4 turn. It wouldn't go in on 1/4 turn, as I didn't bother with instructions I just opened it more till it went in. Probably best parts of a full turn IIRC.
as mentioned with the epic kit yes you have to remove the plunger from the reservoir end. You seem to have everything else cock on so if you can't bleed them with the nipple open a good full turn sounds like you have an issue that's more serious.
What about trying attaching the funnel to the top, filling that with fluid and then pulling through from the caliper end? Maybe something has broken off inside causing a blockage?