Brake Bleeding Sequence

[Colemak 3]

Hello all

 

I'm overhauling the front caliper on my lad's bike, so will be needing to bleed the brakes.  The caliper has 3 pistons and 2 hoses running to it, so I'm assuming it has linked brakes?  It's a 2012 NC700x UK model, with ABS

 

Can someone tell me the correct bleeding sequence please?  Any common problems or tips you could share would be appreciated. Thanks, Nick

[embee 7,288]

As you say, linked brakes. The middle piston of the front caliper is operated by the rear brake, it has NO hydraulic connection at all with the front brake master cylinder. There is a separate bleed nipple for this middle piston.

The outer two pistons are operated by the front master cylinder only, there is NO hydraulic connection with the rear brake. There is a separate bleed nipple (the top one) which serves the outer 2 pistons.

 

I would strongly recommend a vacuum bleeder, I would not even attempt to do it using the "pump the lever" technique.

 

As far as sequence goes, since the front master cylinder and two outer pistons are on their own circuit, you just do it as normal. I always empty the reservoir of old fluid using the vac bleeder, top up the reservoir, then draw fluid through the bleed nipple until perhaps half of the reservoir is emptied (BUT NOT COMPLETELY), stop bleeding and close the nipple, top up the fluid, repeat the procedure and see what it feels like. The NC brakes are a bit "springy" I find, you'll never gat a "hard" lever feel.

 

The rear/linked circuit I do much the same, empty the reservoir of old fluid and refill, bleed the rear caliper, top up reservoir, bleed the front middle, top up, then repeat rear and front again and see what they feel like. I'm not sure if there is a recommended method for the linked circuit, it depends whether there is any air in either line and whether it is all removed in a bleed. If in doubt, draw a bit more fluid through.

 

Using a vac bleeder I have never had any problems in successfully bleeding a combined brake on a Honda bike.

[Colemak 3]

Thanks embee.

[DCTPaul 629]

Generally, start with the caliper furthest away, or on the longest line from the master cylinder...