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08-09 Electric Brake Booster Brake Bleeding WEIRDNESS
Hummer H2For those who like a little more gleam to their Hummer, the H2 offers a similar rugged look as the H1, but as a lower cost, and with more added features, making it almost a massive luxury SUV.
08-09 Electric Brake Booster Brake Bleeding WEIRDNESS
idk how many of you have noticed this on later h2s but gm switched from hydro boost to some weird hydroelectric bullcrap that was also used in the Colorado, h3, and fj cruiser I guess for fuel economy reasons in the recession. It looks like this and takes about a quart to fill the reservoir.
It almost looks like a glorified hydro boost with an electric motor and a massive accumulator(the one pictured has a smaller one)
Just finished installing all new steel lines on my 08 and that’s a whole discussion in itself. Naturally as I waited for parts I just let the truck slowly **** out every ounce of brake fluid.
when I went to bleed the brakes, NOTHING was happening. I would pump 3-4 times and the pedal would firm up and go soft again, but the fluid level in the reservoir would not go down and there was no fluid reaching the brakes. However as soon as I turned the truck on I could hear the pump run and see the fluid level go down. Then it only took about 10 pumps to bleed each of the rear lines.
Does anyone know anything about these electric units and why it behaved this way? I’d like to learn more about how they work.
all the information I have found indicates the master cylinder cannot be bled without a scantool,
First the master cylinder needs to be bled then the brakes are bled
This one unit along with the EBCM controls;
anti lock braking
dynamic rear proportioning
Hydraulic brake booster power supply
traction control system if equipped
vehicle stability enhancement system if equipped
Going to have to replace mine soon, I can feel aeration every so often in the peddle and I have a small leak inside at the push rod.
They are a little pricy from what I remember,
idk how many of you have noticed this on later h2s but gm switched from hydro boost to some weird hydroelectric bullcrap that was also used in the Colorado, h3, and fj cruiser I guess for fuel economy reasons in the recession. It looks like this and takes about a quart to fill the reservoir.
It almost looks like a glorified hydro boost with an electric motor and a massive accumulator(the one pictured has a smaller one)
Just finished installing all new steel lines on my 08 and that’s a whole discussion in itself. Naturally as I waited for parts I just let the truck slowly **** out every ounce of brake fluid.
when I went to bleed the brakes, NOTHING was happening. I would pump 3-4 times and the pedal would firm up and go soft again, but the fluid level in the reservoir would not go down and there was no fluid reaching the brakes. However as soon as I turned the truck on I could hear the pump run and see the fluid level go down. Then it only took about 10 pumps to bleed each of the rear lines.
Does anyone know anything about these electric units and why it behaved this way? I’d like to learn more about how they work.
Added safety feature! ACTIVE BRAKE CONTROL (JL4) :Allows the driver to not exert as much pressure on the brake pedal+StabiliTrak assist.
Hummerz I have also seen that this is used in the fr cruiser, forerunner and Tacoma. I also read and experienced that there is some special programming for the h2 in 4lo mode for torque vectoring and it works really really well. I wonder if it’s similar, if not the same system that Toyota uses with A-TRAC minus having to push a button.
Had My Brake fluid changed on my 09 H2 by my Personnel Wrench Monkey. It was time...that gack should be flushed out every few years or what ever. Anyway, he used a Scan Tool which had program that ran the Motor in the ABS Pump system as he flushed out the old chit. Also had a Pressure bleeder hooked to the MC and all he had to do was walk around and open each bleeder valve and let the old gack and the new gack in. The Pump ran in sequence to the pressure bleeding.
08-09 Electric Brake Booster Brake Bleeding WEIRDNESS
