My first full hydraulic brake bleed . . . using the proper tools!
I have done many quick bubble bleeds but not full bleed before.
I got a reasonably cheap and very cheerful yellow multi-brand brake bleeding kit.
It's very straight-forward with shimano.
The same, a bit more fluid spilled with magura.
Bleeding disc brakes there seems to be a few variants on how to do it, gravity bleed from top. Push fluid up from caliper. Both ways. And there are a few optional lever wriggles to eliminate air from system that vary a bit also. I'm trying to find a simple method that works for me.
My brakes are on the road and off road occasionally and pick up lots of grime and gunge so generally the brake caliper is filthy inside and out. So good to clean everything.
GMBN have 2 videos, pretty close to how Dealer's manual say to do it.
So best steps I think following Dealer's manual closely (but cleaning as we go):
0. Collect tools and cleaning cloths, warm soapy water.
Clean everything as we go.
Raise bike so caliper is at lowest point.
(Note: for rear brake front handlebars probably need to be raised higher.)
Set out a lunchbox for keeping small bits safe and for drying brake pads.
Mineral oils are interchangable, different colours can tell you when you have done full bleed.
Shimano Red was in my front brake as expected but blue blood was in my rear!
There was a little bit of contamination front and rear but not too bad.
1. Raise brake lever to parallel.
Freestroke all the way in. (oops - I didn't do this)
2. Remove wheel. Remove brake pads. Push back Pistons. Fit bleed block spacer. Clean things.
Plastic tyre tool preferred to push back pistons but flat-headed screwdriver might be needed.
Opening the lever reservoir might help push pistons back.
Fit in bleed block spacer.
Inspect pads & clean caliper and rotor and maybe pads (VERY carefully) if they are contaminated.
Set out to dry. Wipe off later with clean paper towels.
Do not touch the face of the brake pads more than necessary. Use very clean brushes/other.
Today rosemary sticks and leaves were used! !? yeah.
3. Remove plug nut at lever (careful of the o ring, keep it with the nut.)
Gently screw on bleed cup (plugged).
4. At caliper, remove dust protector.
Prepare syringe hose with open hose end.
Have 7mm wrench or allen/torx of right size ready for opening caliper.
Fill syringe with clean mineral oil.
Attach syringe to caliper nipple.
5. Unplug the cup at lever.
Open the caliper (1/8 or 1/4 turn).
Push syringe and push hydraulic fluid into caliper. (one video does a little pull here)
If it is reluctant to go don't push too hard! Check correct lever is open. Open caliper a bit more.
You will hear and see it coming into cup.
Tap brake hose and caliper as you do this.
5.1. When all oil is pushed in then close the caliper.
Plug the cup. Take it off. Pour old oil into old oil container.
5.2 Kind of optional steps, reverse bleed, lever wriggles/squeezes, freestroke and lever adjust.
Put cup on again. Put some some clean oil into cup.
5.2.1 Open caliper, reverse bleed (using bottle/baggy) to eliminate caliper air.
Tap caliper and brake hose.
5.2.2 With brake lever pressed do quick open/close of caliper. 2 or 3 times.
5.2.3 Finished at caliper now. Wipe off. Plug.
5.2.4 At lever squeeze lever in and out a few times, flick it a few times,
wriggle lever angle up and down,
screw in freestroke and lever adjust.
Watch for bubbles coming up into cup.
5.3 Take off cup, replace lever plug nut and o ring.
Oil flush with top, don't introduce air.
6. Finishing up . . . brake pads back in . . wheel on.
Wipe off and dry caliper, brake pads and rotor.
Remove bleed block spacer.
Re-install brake pads.
Put wheel back on.
Check wheel spins ok, pads free of rotor.
7. Put lever back in position.
Squeeze lever a few times to move pistons back in so that pads grip rotor.
Test ride. Careful now.
8. Clean syringe and bleed tools with soapy/wash up liquid warm water.
Dry.
Tidy away tools etc.
My commuter Ridgeback vanteo has shimano hydraulic brakes front and rear.
Front brake lever & caliper replaced a few years ago after lever damaged.
Front brake lever on right, shiny silver Shimano De-ore XT freestroke.
Front brake caliper has nipple at highest point and 7mm wrench nut on nipple to open at the caliper.
Rear brake lever on left, all black, original that came with bike.
Very little markings on lever or caliper except for Shimano and very small BL-MS55(or M855?) Malaysia 22.2. ? so maybe of the BL-M8000 series ?
The caliper has bleed nipple cover flush with side of caliper and separate bleed screw.
A bit easier to use.
 |
| Rear brake lever - original to bike - on left. |
 |
| BL-M855 ? |
 |
| Rear brake caliper - FILTHY |
 |
| Front brake lever on right. |
 |
| Front brake caliper, pretty grubby. FILTHY inside. |
 |
| Front brake caliper, a bit cleaner, with spacing block fitted. |
 |
| FILTHY. Washing up liquid and rosemary to scrub. |
 |
| Brake pad surface. Don't touch. ALOT cleaner. |
Diagrams here,
my front caliper is like the BR-M446 with 7mm wrench at bleed nipple,
my rear caliper is like the BR-M395 with bleed nipple to side(but flush into caliper not sticking out) and separate bleed screw at 90 degrees. Easier to use.
