Help with bleeding hydraulic brakes

[Maty]

Hi,

I want to learn how to do a few things on the bike myself rather than relying on the bike shop. First on the list is bleeding the brakes. I can already change pads etc but I'd like to be able to bleed them as well myself.

Bike is an 09 Cube with Shimano BR-M486 brakes and so there isn't a bleed screw on the brake lever like I believe there is with newer hydraulic brakes. I just want to make sure my process is correct...

1. Make sure brake lever is level.
2. Remove reservoir cover.
3. Attach pipe to bleed nipple on caliper with bag to collect waste fluid.

Then this is the bit I'm not sure about:

4. Open the bleed valve.
5. Pull the brake lever as far as it will go.
6. Tighten the bleed valve.
7. Release the brake lever.
8. Top the fluid in the reservoir up again.
9. Replace reservoir cover.

Ignoring the dirt as bike will be cleaned this is what I have:





Thanks,

[Kermit power]

That's basically it. The only thing you're missing is to position the bike in your workstand so that the nipples are at the highest point on the caliper, just to make sure you don't get air trapped elsewhere in the caliper. This is an easy thing to forget if you're used to bleeding car brakes, as obviously they're in the right place by definition assuming you've got your car the right way up!

If you can't find a pipe to fit over the nipple - and where on earth does one buy a short length of pipe, rather than a stupidly over-priced kit? - then you should be fine doing it without if you're careful and have a rag round it. There won't be much coming out anyway, and it's not corrosive like car brake fluid, although obviously not something to do with new pads in just in case you do spill some!

[Maty]

Thanks Kermit...

I'll give it a go!

[barker22]

The other option is to get a syringe and fill it full of fluid then inject upwards from the bleed nippple.
I prefer this way myself as you only have to crack the nipple open once. The important part being you need a good seal over the bleed nipple.

[Kermit power]

barker22 said:

The other option is to get a syringe and fill it full of fluid then inject upwards from the bleed nippple.
I prefer this way myself as you only have to crack the nipple open once. The important part being you need a good seal over the bleed nipple.

This is a cunning plan, but where do people get syringes and tubing? I can't even raid my wife's diabetic stash since she moved to using a pump!

[snotrag]

Almost, but not quite (bled many shimano brakes, lots easier than the rest!)


I've amended -

Maty said:

4. Pull the brake lever as far as it will go.

THEN

5. Open the bleed valve.

Lever will then pull closer to the bars, as you push old fluid out)

6. Tighten the bleed valve.
7. Release the brake lever.
8. Top the fluid in the reservoir up again.

Repeat 4-8 till new fluid is coming out the nipple

9. Replace reservoir cover.

Any time the nipple is open, there should be pressure behind it pushing fluid OUT so as not to allow air IN.

Other than that, make sure your using mineral oil not brake fluid, and if you've a workstand tilt the whole bike so the entire system is as near to vertical as possible, lever at the top.

[Maty]

Thanks,

I've ordered the shimano mineral oil which comes with a tube. Also going to pick up a cheapo bike stand from Halfords to make it a bit easier. I thought about injecting it in at the caliper but then the oil will spill everywhere at the reservoir, won't it?

Also managed to pick up a shimano caliper block on eBay for a few quid so I can take the wheel off as the pads are probably 50% worn.

[agentnomad]

Another trick (ex car one) is to remove the calliper and fit a piece of metal in place of the disc so you can hold the calliper above the resivior. so any air bubbles travel up and are bleed out of the system

[megaphone]

barker22 said:

The other option is to get a syringe and fill it full of fluid then inject upwards from the bleed nippple.
I prefer this way myself as you only have to crack the nipple open once. The important part being you need a good seal over the bleed nipple.

This is the best way I've found to bleed bike brakes.