New 14mm Front Master Cyl. Bleed Question

[IanDMacDonald]

Just a quick question: I ordered the MC that Phil suggested. The plan is to fill it on the handlebar, pump it with my finger over the hole till fluid comes out, then attach the banjo fitting for a final bleed with the bleed screws. Anything I'm missing?

[Schming]

Jat

Hi Ian, You could hook up an old, clean brake line to the MC and submerge the free end in the MC reservoir and work the lever til no air bubbles appear.

Don't forget the rag on the painted parts, but you know that

[bikerphil]

Ian, your method sounds like what I did, it did take a little longer to bleed than ones I've done in the past, YMMV. One thing to remember with a MC with a fluid sight glass is to remove the top whenever you are compressing the caliper pistons, the window may pop out otherwise. GL

[IanDMacDonald]

One thing to remember with a MC with a fluid sight glass is to remove the top whenever you are compressing the caliper pistons, the window may pop out otherwise. GL

I read that sentence out-loud many times before it made sense to me. Gotcha. However, the only time I assume I will compress the pistons will be to change the pads. Some kind of caliper/rotor upgrade is inevitable over the Winter.

[bikerphil]

Some kind of caliper/rotor upgrade is inevitable over the Winter.

With different calipers that 14MM MC may/may not work for you.

[IanDMacDonald]

Well, for $35, it'll work for now, lol.

[MaximPhil]

Pictures Ian remember we need to see pictures of your MC conversion.
Phil

[IanDMacDonald]

I'll take pics of everything pre/post install Phil. It might require a day or so to bust-out the laptop for a more formal review of everything.

[Arthur_of_Hex]

At the bike shop we are constantly cleaning/rebuilding master cylinders. One thing good about bikes is: in most cases if the piston is horizontal, the line is vertical with no loops for air to get trapped, the brake line will bleed itself of air. Leaving only the little bit in the caliper. With Master cylinder and piston level, push lever and hold, wait 5-10 seconds to allow bubbles to climb back up the line toward the MC. Release and repeat, you should see bubbles escape the tiny hole closest to the banjo in the reservoir. The trick is to wait with lever held, the bubbles climb slow. Of course once bubbles end, finish with usual caliper bleed.

Note: once the line is free of air, squeeze the lever much slower or a nice fountain will jet out of aforementioned micro hole

If I missed the question completely, I second the: loop a hose back around from the banjo to the reservoir to prime the master.

[DeanR]

Also good to tie the lever closed overnight to purge the micro bubbles.
and maybe fill from the caliper nipple instead of the m/c.

[bikerphil]

we need to see pictures

Notice how the aluminum cap is oxidizing only after 6 months....