Bleeding brakes

[ak diesel driver]

Anyone know the proper procedure for bleeding the brakes ont these things. Put on new calipers and can't get a firm pedal anymore. I thought I read somewhere about having to bleed the abs first. thanks

 

[Big T]

Anyone know the proper procedure for bleeding the brakes ont these things. Put on new calipers and can't get a firm pedal anymore. I thought I read somewhere about having to bleed the abs first. thanks

Best done with two people; one working the pedal the other the bleeder. Start with the furthest wheel first: passenger rear. Open, pump, close. Repeat. That's the only way I know and there is no bleed of the ABS that I know of. I did brakes all around this summer on mine and they're as firm as an 18....err 30 year old.:rolleyes5:

 

[ak diesel driver]

That's what I did and no go probably went thru more than a quart of brake fluid.

 

[Big T]

I recall going through a lot of fluid and experiencing the same, wondering if she would ever get firm. Eventually she did. The power brake system will mis-lead you as the pedal seems to float down. If it floats down to the floor, you need to bleed more. If it floats down 1/2 way, you're there.

 

[ak diesel driver]

I never did totally stop getting air. Slowed way down but never would stop. Never had this problem before. All I did was put new calipers on shouldn't have had any air except right at the caliper.

 

[Big T]

Rotate the crank position sensor 180:thumbsup:h

Put it down, crack a beer, think it through and go at it again.

 

[ak diesel driver]

LOL

 

[JiFaire]

ROFL - you guys kill me ... gravity bleed them, AK. Top off the master cylinder resevoir, put a hose on the bleeder, on each front wheel, put that into a jar to collect the brake fluid. Remove the cap on the master cylinder, open the bleeders and let it sit. Go out and check to make sure the master cylinder doesn't run dry.

Once you have the air out of the system, grab a partner and pressure bleed them again. Should be good to go!

 

[Big T]

ROFL - you guys kill me ... gravity bleed them, AK. Top off the master cylinder resevoir, put a hose on the bleeder, on each front wheel, put that into a jar to collect the brake fluid. Remove the cap on the master cylinder, open the bleeders and let it sit. Go out and check to make sure the master cylinder doesn't run dry.

Once you have the air out of the system, grab a partner and pressure bleed them again. Should be good to go!

I like that approach. In keeping with crack a beer.:thumbsup:

 

[Woody35]

if my memory serves me correctly it took me a long ass time to get all the air out of the brakes

 

[Matt Bachand]

Try bleeding the rears also.

I've replaced both calipers and rear brake lines and did not have to bleed ABS anything differently. Unless you got the master airbound? Did you clamp off the caliper lines to prevent full fluid loss and air fill?

 

[ak diesel driver]

Well I got her done. Still feels different. Might just be the new calipers are less stiff I don't know. The old ones had 220k on them.

 

[Tookie]

I ended up having to bring mine to a dealer, they have the scan tool to
cycle the ABS on, so it will pump the trapped air out. I think it eventually
will push the air out without doing this, but I got tired of bleeding them.

 

[Turbine Doc]

I used a mity-vac to pull bulk of air, then tried & true 2 person pump-hold-vent method for final bleeding.

 

[Chevylover]

I ended up having to bring mine to a dealer, they have the scan tool to
cycle the ABS on, so it will pump the trapped air out. I think it eventually
will push the air out without doing this, but I got tired of bleeding them.

That is what I got in my mind ! You'll need a scanner to bleed them right, if ABS equipped, IIRC !

Cu,
Sven

 

[540s10]

That is what I got in my mind ! You'll need a scanner to bleed them right, if ABS equipped, IIRC !

Cu,
Sven

GM says you bleed them as if the ABS isn't there, and you ONLY need to activate the ABS to bleed them IF you replaced one of the ABS solenoids.

I do the normal open- down- close- up procedure about 5-10 times, and then pump 5 times and hold, open, close., and then open- down- close- up a few more times, always works.

 

[bison]

GM says you bleed them as if the ABS isn't there, and you ONLY need to activate the ABS to bleed them IF you replaced one of the ABS solenoids.

I do the normal open- down- close- up procedure about 5-10 times, and then pump 5 times and hold, open, close., and then open- down- close- up a few more times, always works.

X2,if the pedal feels spongy,bleed the rears as well.
proper procedure is to bleed the shortest line first.LF,RF,LR, RR.And repeat if needed.

 

[GJF]

IIRC GM suggest a vacuum bleed system that pulls from the master to each wheel. I have a Snap On vacuum brake bleeding unit. And it works perfectly everytime.

 

[SmithvilleD]

I borrowed a neighbor's power/pressure bleeder. The one from Motive products. Pretty slick idea.

It's basically like one of the little pump up garden sprayers. You fill the power bleeder's tank about halfway up w/ brake fluid. The power bleeder's hose goes to an adaptor that replaces the brake master cylinder reservoir's lid/cap.

Then screw on the power bleeder's pump handle (again, pretty much like the garden sprayers) & pump up to put a few lbs of pressure pushing brake fluid from the power bleeder tank into the master cylinder reservoir.

Then go back to the right rear brake & crack the bleeder valve. You've only got a few psi of pressure pushing the old fluid out, so it doesn't come squirting out as rapidly as the tried-n-true 2nd guy pressing the brake pedal. But it does work pretty well for just 1 person.

And since the power bleeder is pushing new brake fluid into the master cylinder reservoir, you don't have to worry as much about the master cylinder reservoir running empty, then letting air into the system, forcing you to start over.

Only issue I had was the seals btwn my truck's master cylinder reservoir & the metal plunger body couldn't contain the 8-10 psi pressure the Motive Product's instructions recommend. Anything over 4-5 psi would push brake fluid past those seals - don't suppose they're really designed to contain pressure beyond gravity.

After having this system work well for bleeding brakes, I wish the tranny slave cylinder's had a different bleed valve setup that would allow connecting this power bleeder. If there were a way to use the power bleeder to push fluid back up the line to the clutch mc quickly, it might make bleeding the clutch hydraulics faster/more effective.

 

[Jess_sr]

BLEEDING PROCEDURES As per Alldata

Important: Never pump the brake pedal. Fluid cavitation may occur.

NOTICE: Gravity and vacuum bleeding are not recommended for this ABS system.

Two Person Procedure (Preferred)


1 Raise the vehicle to gain access to the system bleed screws. Install clear tubing on the bleed screws so that air bubbles in the fluid can be seen.
2 Begin by bleeding the system at the right rear wheel, then the left rear, right front and left front.
3 Open one bleed screw at a time 1/2 to 1 full turn.
4 Slowly depress the brake pedal until it reaches its full travel and hold until the bleed screw has been tightened. Release the brake pedal and wait 10-15 seconds for the master cylinder to return to the home position.

Important: Repeat steps 1 through 4 until approximately 1 pint of brake fluid has been bled from each wheel. Clean brake fluid should be present at each of the wheel bleed screws. Check the master cylinder fluid level every 4 to 6 strokes of the brake pedal to avoid running the system dry.



5 If any component is replaced which may have caused air to enter the BPMV, use a Scan Tool to run "Function Test" four times while applying the brake pedal firmly.

Important: Set the park brake when running the "Function Test."



6 Rebleed all four wheels using steps 1 through 4 to remove the remaining air from the brake system.
7 Evaluate the brake pedal feel before attempting to drive the vehicle and rebleed as many times as necessary to obtain appropriate pedal feel.