street_ride14

Hello guys, I need your help ..

This is driving me crazy! ..
So after doing the Legend twin-piston front caliper upgrade, I bleed the brake system in the sequence illustrated per Helms manual, with the motor off. Pressure builds as air is forced out of the brake lines substituted with new brake fluid. ..
Now, engine is turned on and brake pedal suddenly loses all that pressure! .. I have no brakes, pedal still comes up on its on after being pressed down, but no pressure. .. after this I bleed the system 3 more times and same story, pressure goes to near zero when engine is on .. help!

.. What is going on with my brake system ?

street_ride14

Also wanted to add .. installed both my Legend calipers with the bleeder screws pointing down instead of up. .. Air pocket trapped inside calipers? .. Could this be the cause?

Drive 4 fun

To start you need to get the air out. I do not see how it is possible to get the air out of the system with the bleeders down. I have that on the back with RSX caliers on an Integra, and I have to take the caliper off and hang it with the bleeder up to keep air out. Either switch sides for the calipers, the drawback of Legend calipers, or take them off of the brackets and hang them with bleeders up at the highest point to remove the air. You may have air up into the system as air bubbles can go up the lines. I cannot tell about the booster from the description, but get the air out first.

street_ride14

okay, will turn them upside-down for the bleeding phase, will report back, thanks.

street_ride14

all fixed,
the cause of the problem ended up being in the bleeder valve location .. caliper was mounted with bleeder valve being on the lower end instead of the upper end of caliper (trapping air at top of caliper), took the front calipers off and turned them so that bleeders were pointing up, bleed the system, and now have constant brake pressure .. thanks for working through this with me guys!

Dogginator

And Kudos to you for mounting directional calipers in the correct direction. Did you use a block of wood for the bleeding process?

JTypeR89

Bleeding during brake system upgrades i've found to be time consuming. This is common problem with a simple solution. Good Thread & solution

el crapitan

Or you can use a power bleeder