My Brakes Suck!

[adallak]

Adallak,

That would work. You have to make sure the reservoir stays full.

My power bleeder is a tank that pressurizes and has an outlet near the bottom. It is similar to the homemade unit Ranger linked to but is metal.

Yes, it should work. Besides, the 12V compressor which may be attached to the lighter makes the job faster. My only concern is how many PSI that compressor provides. Using a valve stem instead of a standard air fitting makes the job even faster.

Ranger,

Thanks for the link. I am going to try this valve stem and 12V air compressor setup when I finally replace my brake lines (some look really bad) As I told before, I was never happy with the braking ability of my car and never could fix it.

adallak, I would think you would need some type of pressure regulator and pressure guage on your 12V air compressor. The sites I was reading referring to power bleeders mentioned the air pressure shouldn't exceed 15-20 psi, or damage could to your system could occur. Don't those little 12V AC's put out more than that? I've used them and pumped up tires to over 35 psi.

Epricedright,

I am pretty sure the 12V air compressor is safe for the thask. The matter is that the pressure itself does not mean much without taking into account the crossection of the output, and the latter is really small. I will definitely try this in a week or so and let you all know what happens. LOL

[nigel]

hi, i've been reading through this topic and thought that i could add something constructive.

my sts has had a really bad pedal feel and while i could stop the car, i could very rarely get the abs to activate and i often thought i was going to hit things, my own account almost exactly matches that of boatboy, new rotors, pads and loads of manual bleeding.

but here's what i now know, the fault is with the abs modulator pump.

the brake fluid should be completely changed regularly, if not it becomes contaminated. this is not a problem as such but when changing front brake pads the easy way to fit the new pads is to wind the pistons in the calipers back. this forces old, dirty fluid into the abs modulator valve and can cause the accumulator valve to stick.

when applying the brakes the fluid can then flow into the accumulator, giving the feeling of a soft pedal. basically the master cylinder does not have enough travel and capacity to fill the accumulator and apply pressure to the front calipers.

if you hook up to a tech 2 and have the auto bleed sequence carried out then you may free up a stuck valve but don't count on it.

since fitting a new pump my brake pedal is nice and firm.

[nigel]

forgot to say that since the fault in the abs pump is mechanical and not electrical, a dtc won't be registered.

because there is no code many mechanics overlook the abs system as a source of trouble.

my car has the delco-bosch 5.3 system.

i also belive that some cars were recalled due to faulty abs pumps, i think they were 2000 models

[adallak]

hi, i've been reading through this topic and thought that i could add something constructive.

my sts has had a really bad pedal feel and while i could stop the car, i could very rarely get the abs to activate and i often thought i was going to hit things, my own account almost exactly matches that of boatboy, new rotors, pads and loads of manual bleeding.

but here's what i now know, the fault is with the abs modulator pump.

the brake fluid should be completely changed regularly, if not it becomes contaminated. this is not a problem as such but when changing front brake pads the easy way to fit the new pads is to wind the pistons in the calipers back. this forces old, dirty fluid into the abs modulator valve and can cause the accumulator valve to stick.

when applying the brakes the fluid can then flow into the accumulator, giving the feeling of a soft pedal. basically the master cylinder does not have enough travel and capacity to fill the accumulator and apply pressure to the front calipers.

if you hook up to a tech 2 and have the auto bleed sequence carried out then you may free up a stuck valve but don't count on it.

since fitting a new pump my brake pedal is nice and firm.

Probably it makes sense to open up the bleeding screw instead of removing fluid from master cylinder reservoir while bottoming a caliper piston. This way an old and possibly contaminated fluid will not get farther into the system.