Bleed rear brakes?

Shepherd

Joined
Nov 10, 2020
Messages
13
Location
Essex, U.K.
It's time I came out of 'lurking mode' after hiding for a few months - so might as well ask a question :)
I have a slight binding on the front brakes, so decided to be big and brave and give the calipers a clean up. I removed all the pistons to get them as clean and smooth as I could, including the centre left that is part of the rear system.
I still have air in the system after bleeding through 3 reservoirs of dot 4, so I'm leaving the lever halfway pulled overnight to see if the fairies and pixies help.
Do I have to bleed the rear caliper too? If so, how to get to it? Reading through every post about brakes on this great forum of information, it looks like I remove the pannier on the right hand side. Is this still the easiest way to get access?

Thanks in advance,

Shep
 
Yes, removing the left pannier is the easiest way although I've done it "by feel" without removing the pannier but that always left me with a feeling of not doing it correctly. With the pannier removed you can clearly see the caliper and also the bleeder bolt.
 
You can do it without removing the pannier.

Get about an 18inch length of clear hose that fits firmly over the bleeder (from memory it is 3/16” hose). Place a ring scanner on the bleeder and then fit the hose over the bleeder with the hose going up above the bleeder.

Crack open the bleeder and apply pressure to the rear brake. Once the pedal bottoms out close the bleeder and let the pedal return to its normal position. Repeat until clear fresh fluid with no bubbles is coming from bleeder. Good brake feel should retun after three or four cycles of bleeding.

It may also help to have a container to catch the fluid coming out of the clear hose.

Seagrass
 
Shep,
You may want to invest in one of these. https://www.amazon.com/MV8000-Autom...=1609301713&sprefix=mighty+vac,aps,281&sr=8-5
It makes changing clutch and brake fluid easy. It will also draw any air out. I changed the brake fluid on my NT and did not have to remove any panels. It connects on to the caliper bleed bolt and extracts fluid and air through there. You just need to top up the brake reservoir as you bleed out fluid.
 
Thanks guys (y)
I got stuck with one bolt in the pannier rounded off, so couldn't get the job done completely. I did bleed the fronts again, including the centre piston on lhs, and it seems I have pressure in the brake lever again - happy days.
I know I should do the rears, but I'll wait for warmer weather before attempting again. I have a one way valve/bottle combi thing, which meant not having to buy a mityvac this time, but will invest in the spring when I do the job properly.

On to the fork seals next ... :rolleyes:
 
If you unbolt the front calipers from the forks, remove them from the rotors, and tie them up to the forks so that the crimps in the hoses are the highest spot, a lot of the air in the calipers will slowly work it's way up to the front master cylinder, if you leave it sit for a couple of days. Leave the front brake lever fully released when doing this, so the front master cylinder piston exposes the return passage in the cylinder. You don't need to remove the master cylinder cover to do this procedure, but check the level after the calipers are bolted back up.

Brad
 
@ rc_heli_nut
Thanks for this tip - I think I'll give that a go (y)
Having gone for a short journey today, I notice I had to pump the lever one time to get resistance before travelling. It wasn't an issue after, but there must be a little air left in the lines.
The weather is turning, so I have time to do the above, and still have the 125 to get by with.
 
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