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My front road brake is locking on/rubbing so i'm guessing a bleed is needed.
There are two completely different ways of bleeding i've found online -
Cyclist show a gravity fed bleed from top to bottom with some squeezing of the lever
BikeRader bleed bottom to top https://www.bikeradar.com/gear/article/how-to-bleed-shimano-road-bike-disc-brakes-43717/
I'm thinking about trying a combination of both - when I bled XT's the fluid was filthy. Pushing the dirty fluid from the caliper up the hose to the lever seems a bad idea but bottom to top seems like a good way of getting bubbles out.
Also, where do i buy one of those neat little clips for the bleed nipple that is shown in both of those videos (without buying a full kit as I've got all the other stuff I need)?
you'll probably find its more likely a build up of brake dust and crap round the pistons. I'd give them a push out and good clean 1st.
With a new brake I always do a bottom to top bleed for Shimano with the bleed bucket and syringe, never failed to get a good bleed that way. However, with old oil I might be tempted to fill up the bleed bucket and flush downwards 1st, then from bottom to top with clean fluid.
This worked perfectly on mine.
That makes sense.
I gravity bled from the top. Stuff that came out of the front was black. Rear wasn’t nearly so bad (and was also clear not pink so i suspect rear was bled with non-Shimano fluid when the bike was built onto a replacement frame shortly after I got it). Front also seemed to have quite a bit of air in it.
Then pushed some in with a syringe.
Very odd feature on the 785 callipers - pad retention pin has a flat head screwdriver slot. I’ve never seen that on any Shimano part before.
I push a syringe of fresh fluid from the caliper end to a funnel in the lever.
Empty the funnel of old oil, put some fresh fluid in it and pump that into the now empty syringe. Pull lever> open bleed screw (fluid comes through)> close bleed screw> pump lever a couple of times > repeat until funnel is almost empty. Close the bleed screw and remove the syringe.
Once that's done I just pump the lever a lot whilst taping the hydro hose\lever\caliper to loosen any trapped bubbles, a minute of that should do the trick if anything is trapped.
Remember to use an appropriate sized bleedblock.