swapping brake fluid: taking FOREVER to bleed the air!!

[snuff58]

Ok, so I am replacing lines at wheels w/ braided SS. And flushing OEM fluid w/ Motul rtb600. Started w/ rt rt. changed line. started vacuum bleeding. took a long time, but finally no air.
Went to lt rr, same, but the air in the line is going on forever!!!. Started to use pedal pumping along with the vacuum pump. It got too late, so I stopped. Why is this taking so long???

'14 BRZ ltd

[snuff58]

um started w/ right rear

[ryoma]

what order did you go? you're supposed to go rear passenger side > rear driver side > front passenger side > front driver side. I have no idea what lt and rt mean

it is usual for air to come out when bleeding after changing lines, but it definitely shouldn't take too long unless you had air in the system prior, or let the master cylinder run dry and cause it to pull in air. how long is long? 5 minutes? 10 minutes? how many bleeds did you do? open the nipple for like 3-5 seconds then close it. did you start seeing clear fluid?

[snuff58]

Sorry for confusion. Left hand drive car. Order of bleeding: passenger rear (rt (right)rr, driver rear (lt (left) rr), passenger front, driver front. Yes, I expect a lot of air, since I am changing the brake lines at the wheels. I am monitoring the master cylinder reservoir, and not allowing it to run out. My connections are tight. No apparent leaks. I am curious if anyone else has found a lot of air in the system during the bleed. The brakes were working fine: no sponginess.

[Mr.ac]

did you make sure you have enough brake fluid in the reservoir? and not let it go empty?

[snuff58]

Oh yes! kept a good eye on reservoir!

[wparsons]

Sounds like it wasn't enough vacuum to work faster, more pressure differential would speed it up.

[bhmax]

Haven't done this car yet, but on other cars while using a vacuum bleeder I've had air seem to get from atmosphere through the bleeder threads making it seem air is still in the system. Fixed those by using thread sealant on bleeders just prior to bleeding(once dry, it seemed to allow air back through on the next bleeding months later). Finally got a Motiv pressure bleeder and all is right with the world now.

[snuff58]

bhmax:
the bleeder nipple gave me some pause,..... maybe that is it. I'll tape it up before I continue.
I will let everyone know how this proceeds!

[snuff58]

UPDATE: My first track day, 2 days ago, went without a hitch! Mid-Ohio Sports Car Course. AutoInterests acclimation program. I will need work on gear shifting and shift timing!
Prep summary: replaced wheel studs and nuts. replaced brakes lines at all wheels w/ braided lines. The bleeding process took a long time, and replaced fluid w/ Motul RBF 600. The bleeding never completely was void of air, but the pedal was solid. Replaced all stock rotors w/ Centric #'s 120.47031(rear) and 120.47021(front). Replaced all brake pads w/ Carbotech XP8's. The bedding process went very well using country roads. Ran the stock Michelin Primacy HP's.

bhmax: I did not add any sealing tape to the bleeders, just kept it up...

[Pat]

How far are you opening the nipple? Sometimes if you don't open it enough there won't be enough flow to force out any bubbles.

[snuff58]

Pat:
about 1/3 to 1/2 turn. I gauge it on perceived flow in the clear tubing. My ending results were good. Very solid pedal and no fade at the track under hard braking.

[solidONE]

Google "reverse brake bleed" It can be done with or without special tools (gravity fed reverse bleed). Once you do it this way, you wont go back to the standard way of feeding fluid from the reservoir.

[stevesnj]

may need to open the bleeder a little more. Use your vacuum pump and once you think you have new fluid through close the bleeder with the hose end still on. then remove the hose and open the bleeder slowly till an even dribble comes out I let it dribble for 15-30 seconds just to be sure Been doing this way for a while with no issues ever.