Abs Brake System Fluid Replacement

[pm26]

I aksed this question already in the light truck forum, but need a confirmation from a GM tech on this. Is there any special procedure required when manually bleeding the ABS equipped brake system? I am just replacing the fluid and intend to use a length of tubing attached to each bleeder, with the other end submerged in a bottle partially filled with clean brake fluid, and pumping the brake pedal several times for each caliper/wheel cylinder. The truck is a 2006 Z71 with rear drum brakes.

would it be better to use a vacuum pump such as MityVac to bleed the system?

[pm26]

I asked this question already in the light truck forum, but need a confirmation from a GM tech on this. Is there any special procedure required when manually bleeding the ABS equipped brake system? I am just replacing the fluid and intend to use a length of tubing attached to each bleeder, with the other end submerged in a bottle partially filled with clean brake fluid, and pumping the brake pedal several times for each caliper/wheel cylinder. The truck is a 2006 Z71 with rear drum brakes.

would it be better to use a vacuum pump such as MityVac to bleed the system?

 

[pm26]

[TBLAZER]

I aksed this question already in the light truck forum, but need a confirmation from a GM tech on this. Is there any special procedure required when manually bleeding the ABS equipped brake system? I am just replacing the fluid and intend to use a length of tubing attached to each bleeder, with the other end submerged in a bottle partially filled with clean brake fluid, and pumping the brake pedal several times for each caliper/wheel cylinder. The truck is a 2006 Z71 with rear drum brakes.

would it be better to use a vacuum pump such as MityVac to bleed the system?

There is no special procedure to change the brake fluid,just don't introduce air into the system,the easiest way is to use a pressure bleeder but the manual system works just as good only slower,MityVac works fine just keep the fluid reservoir from running out of fluid no matter what system you use.

[C & A s Dad]

Pete, some disagree with my method and I understand why, but I will tell you what I did.

 

First off I used Valvoline's Synpower fluid for my replacement. It is a synthetic Dot 4 formula that can be used in Dot 3 or 4. It has a higher boiling point than conventional fluid.

 

I pulled my fluid out of the M cyl with a large cleam suction needle and refilled it. I then used the truck as normal for a few weeks, the fluid became somewhat darker during this time and I replaced it again. This time the fluid did not darken up for about a month or better and then I could see a slight change in color. I changed it again, and it has remained pretty clean.

 

I realize this is not a total flush but the fluid does mix to some degree as the brakes are used. If it did not mix, the fluid in the reservoir would always remain clear and this is not the case.

 

I just was not comfortable with bleeding the ABS equipped system and the truck had no other issues that required it going to the Dealership. One day, I will need to take it in and I will likely have them do a total flush.

 

Just my .02.

[Giant]

My Yukon has just recently been in an acciden, and while pulling off loose/broken parts, I found one of the lines from the master cylender to the ABS controler to be kinked.

 

What happens if I do get air in the system?

[TBLAZER]

My Yukon has just recently been in an acciden, and while pulling off loose/broken parts, I found one of the lines from the master cylender to the ABS controler to be kinked.

 

What happens if I do get air in the system?

If you get air in the brake lines calipers or cylinders you just do a normal brake bleeding procedure,If you get air in the ABS valve then you need to use a scan tool to bleed the ABS valve assembly folow by normal bleeding procedures.

The ABS Valve has a series of channels that are normaly closed soo when you bleed the system is just like a non ABS system,but if there is air in the lines and you drive the vehicle and activate the ABS by hard braking you can introduce air into the ABS Valve and it will get trapped in the valve,at the same time if there is air in the ABS Valve and perfome severall hard braking events and cause the ABS to activate the air may get pushed out of the ABS Valve and into the lines,Now this can be DANGEROUS as air in the system can caused the brakes to fail.

[cerbomark]

I usually use the EZ Bleeder but C&A has a good idea that I ve never thought. His way would be ideal if you have any doubts.

[KB06YUKONXL]

The fluid at the calipers or wheel cylinders is where it takes the beating and high temps. So you want to flush the whole system versus cleaning out the MC.

[C & A s Dad]

KB, You are correct but this is why I did it 3 or 4 times. I realize it is not the best method but it helps if someone is not comfortable with the bleeding process. I still plan on doing the entire system when I get it back to the dealer.

 

 

Mark, would you please remove the picture of your truck? That is a gorgeous ride and each time I see it, I have an uncontrollable urge to go the dealership and trade in my "paid for" Yukon XL. So far I have been able to control myself but I am not sure how much longer I can hold on.