Article [13] ST1300 - Brake Maintenance - Getting all the air out of the brake system

[jfheath]

A detailed look at the process of getting the air out of the Honda ST1300 brake lines. A sequence of diagrams of the brake circuits, colour coded to show which parts of the system are being accessed when each bleed valve is opened and explanations of where the trouble spots are.

These are just small thumbnail images of some of the pages. Load the attached pdf to get the full document.






Prior to that, it is worth taking a look at a couple of videos. I had a picture in my head of how the bubbles would behave - that bubble would collect together at the highest point of the line and that if I pumped the lever fast enough that would take the bubbles with it.

I was surprised at how wrong I was.

First - a sealed jar of water coloured with black ink. I was blowing steadily into a tube fed into the jar, pushing the fluid down the tube. I am pointing out the location of trapped bubbles. Sorry - no commentary. I cannot talk and blow at the same time !

And another, this time sucking on a long tube on the left of the video as the fluid negotiates an 'n' shaped bend. I am sucking continuously all the time the video is playing - the fluid looks static in one or two places, but it is actually flowing through that long vertical air bubble. The video stops as the fluid is about to reach my mouth.

Click the link below to download the pdf file.

 

[Dave.David]

Re: Going on an Air Hunt

Brakes - Getting Rid of All of the Air

Below is a link to an article that I wrote a while ago for our biking club, specifically for the ST1300.

Click the link --> View attachment 180023


Full step by step diagrams of the brake system, showing the parts in relation to their height above the ground, along with notes and likely locations of air traps, and some pitfalls to avoid. I hope it will be useful to members.

Thank you for this information. Well done and clear, love the pictures.

 

[usedtobefast]

wow, awesome information! Thanks!

 

[MajorTom]

Thanks for the effort it took to make this article John. While I've done a brake bleed/fluid change on my STeed a couple of times, the last with a hand vacuum pump, your article makes it much clearer what's going on during the process and provides lots of helpful tips to make sure it goes right. For example, I'll be wrapping the bleed valves with teflon tape and using a Motion Pro check valve next time.

At the end of the article you say, "A frequent check on the SMC ‘feel’ is essential to verify that this line remains air free." Sorry, but I don't understand your meaning here. How do you check/detect the SMC 'feel'?

 

[Dave.David]

What is SMC?

 

[Soontobeone]

Secondary Master Cylinder = SMC
View attachment SMC.pdf

 

[Dave.David]

Secondary Master Cylinder = SMC
View attachment SMC.pdf

Thank you

 

[MajorTom]

Thanks John, that clears it up. :bow1:

 

[Dave.David]

With the bike up on the center stand and me laying down next to it I could use my foot to spin the back tire and my hand to shove the left caliper forward. I'm not saying this is a perfect test but it did stop the tire.

 

[Phil h]

Re: Going on an Air Hunt

This fixed my problem many thanks!

 

[Igofar]

Re: Going on an Air Hunt

This is a GREAT video showing folks the reason you should tap all the fittings/housings/bends/connections when bleeding your brakes, rather that just rely on watching the fluid!
I would suggest to also wiggle and push the plunger on the SMC when bleeding for the very same reason.
Both the clutch and brake master cylinder have casting shapes that trap air just underneath them. The handlebars should be turned in both directions slowly while tapping the housing to release this air.
Thanks for sharing.
Larry - Igofar

 

[Ph8]

I can download the file but I keep seeing the raw java script. How do I deal with this on a mobile device?

 

[Honda-st-team]

Thanks for the great info

 

[SupraSabre]

Good reference!

Thanks for sharing!

 

[Dave.David]

PM sent

 

[flip-flop]

awesome! I loved the part about not using water and ink in your brake system! LOL.

 

[jmcarruth]

Thanks! I used the MightyVac and clones for years, sometimes still do. Then I took a chance on this little jewel. Works great for me.

https://www.harborfreight.com/pneumatic-brake-fluid-bleeder-with-auto-refill-kit-61912.html

 

[ColinW1981]

jmcarruth,
I have similar, Motive Products, but cannot come up with a working adapter for the ST (I have the cages version but Motion Products don't list a Honda bike adapter). What did you use? Currently I use the 'bungee' cord method (strapped to the appropriate lever/pedal).

 

[cjames431]

I have done two bleeds since rebuilding my SMC and still have a soft peddle. Back to the bleeding..

 

[cjames431]

Don't forget the tapping and the flexing. - Oh and watch the video to see what may be happening inside the tubes.
I find cursing helps too. It doesn't do owt to get rid of the air, but I feel better.

It's after watching the video that woke up the little grey cells to whats going on. I try to save the cursing for after the work is accomplished and I am out riding and have experienced pucker after scaring myself because some odd bit has just departed the bike. Not really. Plenty taking of Harley Davidson in vain while working.