GM Tech II needed for ABS bleed
- Thread starter Bonj87
- Start date
I do not believe that any of the newer obd2 cars that would require the tech2 would have the old style ABS systems where you have to home position them to get the system to bleed.
Almost all are now self bleeding or have internal bleed screws.
Disregard my comment if you have an older than 95 ???? SS
Almost all are now self bleeding or have internal bleed screws.
Disregard my comment if you have an older than 95 ???? SS
talked to my fellow hack...generally you avoid air getting into the abs, but if the system was not cycled (battery disconnected during brake repair/key cycling) it generally doesn't get air into those bleed/apply circuits.
but yeah, on more than a few they've swapped in the speed bleeder valves and done a few abs stops in the gravel back lot (parking brake works great to get it to sense lockup and activate) after a [primary bleed with the bleeders just open enough for a leak that pushes
just crack the bleeder after an abs stop (driver still holding pedal).
its roundabout and annoying if you cant reach the bleeder with the wheel on.
even if you don't want your wheels to get fluid'd'd and yank em, just a couple times of abs would get the air out of the solenoids.
so you don't need the tech 2, it just activates /cycles the solenoids to get the bubbles out....so yeah, just trigger em in a more labor intensive way if you don't wanna pay for the tech2
but yeah, on more than a few they've swapped in the speed bleeder valves and done a few abs stops in the gravel back lot (parking brake works great to get it to sense lockup and activate) after a [primary bleed with the bleeders just open enough for a leak that pushes
just crack the bleeder after an abs stop (driver still holding pedal).
its roundabout and annoying if you cant reach the bleeder with the wheel on.
even if you don't want your wheels to get fluid'd'd and yank em, just a couple times of abs would get the air out of the solenoids.
so you don't need the tech 2, it just activates /cycles the solenoids to get the bubbles out....so yeah, just trigger em in a more labor intensive way if you don't wanna pay for the tech2
yeah id rather not play like that on a gravel road esp since I put some decent money into some paint work late last year. we're having an issue bleeding the rear brakes more than anything.. pump 4 times.. hold.. crack the bleeder.. not much come out until I mash the pedal to the floor then a bunch of air comes out.. the pedal (mind you I did a hydroboost swap) is spongy and soft. I know there is air in there, I figured it was in the ABS since I never feel the ABS activate anymore.
The mashing to the floor to get air out of the rear brakes is a Cause by the proportioning valves on the two rear circuits.
If you did a hydroboost swap you probably didn't even have to pull/replace the master cylinder. Hydroboost is always on for people to get used to because it is hydraulic assist not vacuum assist you end up with far better power assist with the hydraulics but it can feel weird when you're using the steering as well as applying the break if you do not have the correct power steering pump spring and valve orifice
With the proper pump you'd be even more likely to have the spongy pedal remember a vacuum assist does not provide the assist the hydroboost US I am sitting in a hydroboost powered Chevy truck that has been properly blood and does not even have abs and it's pedal is still spongy if I wanted to I could try to push it all the way to the floor and try to blow a line somewhere.
With vacuum assist the assistance it helps you with is far less then with hydraulic where it will continue to apply pressure even past where manifold vacuum no longer assist you unless you're pulling 28 inches of manifold vacuum.
You may want to test drive and actual hydroboost powered truck so that you can get the idea of what I'm talking about. but get used to being able to push down harder and get the pedal to go farther....
With vacuum assist the assistance it helps you with is far less then with hydraulic where it will continue to apply pressure even past where manifold vacuum no longer assist you unless you're pulling 28 inches of manifold vacuum.
You may want to test drive and actual hydroboost powered truck so that you can get the idea of what I'm talking about. but get used to being able to push down harder and get the pedal to go farther....
If you're uncomfortable with damaging your paint on a gravel lot buy a couple bags of pea gravel or sand and spread it in a parking lot in a straight line so that it only affects one side of the truck that should keep you from damaging your paint but still cycle the ABS so you can try to get the air out I'm going to guess that you did manage to introduce air into the system especially since between then and now you probably have engaged the ABS solenoids.
Without the tech2 you can trigger it by driving or trigger the solenoids with a junkyard harness that way you can sit in the driver's seat and use a 9-volt battery to cycle them
Without the tech2 you can trigger it by driving or trigger the solenoids with a junkyard harness that way you can sit in the driver's seat and use a 9-volt battery to cycle them
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