Why do ABS brakes grab and push air?

SOURCE: no brake lights

Took my Trailblazer to dealership. They replaced both rear tail light socket boards (these are plastic parts that house all of the rear lamps/bulbs and attach to tail light housing) They advised the sockets in the boards have a tendency to go bad. Everything works just fine. Cost of each part was approximately $29.00. Easy to replace yourself and save the labor.

Ned C Cook

• 3433 Answers
• Posted on May 25, 2009

SOURCE: hard brake pedal hear air leaking when pedal pushed

When you press on the brake? Have your brake vacuum assist checked. It,s that bigspaceship looking thing between the brake master cylinder an firewall. good luck and be safe.

SOURCE: ABS & park brake lights come on after about 10 min. of hwy drivin

there is a problem with your abs sensor ....sounds like the sensor is applying the breaks for you when it shouldn't ....have a mech. look at it ...the e- brake issue could be causing a fault in the system ....all the symptoms may be the car.s computer,s way of telling you there is a problem "please bring me in "

SOURCE: Does my truck have abs brakes? It is 4x4 1992 chevy 1500

Your truck is equipped with RWAL or rear wheel anti-lock. This just worked on the rear brakes(duh) but the speed sensor was taken from the speedometer drive at the transmission tailshaft, and would allow one rear wheel to lock as long as the speedo kept turning. Later models were improved with wheel speed sensors at each wheel.

Jeffrey Turcotte

• 8991 Answers
• Posted on Oct 10, 2010

SOURCE: I hve a 96 chevy

you may have air trapped in the ABS EHCU. Did you use this procedure?

Bleeding the EHCU

Bleeding the EHCU requires the use of the TECH-1 scanner or its equivalent and the appropriate cartridge. Additionally, 3 tools, J-39177 or equivalent, are required. Bleeding cannot be performed without this equipment.
The EHCU must be bled after replacement or if air is trapped within the unit. It must be bled after bleeding the master cylinder and before bleeding the individual wheel circuits.
The Internal Bleed Valves on either side of the unit must be opened 1 / 4 - 1 / 2 turn before bleeding begins. These valves open internal passages within the unit. Actual bleeding is performed at the two bleeders on the front of the EHCU module. The bleeders must not be opened when the system is not pressurized. The ignition switch must be OFF or false trouble codes may be set.

1. Open the internal bleed valve 1 / 4 - 1 / 2 turn each.
2. Install one tool J-39177 on the left bleed stem of the EHCU. Install one tool on the right bleed stem and install the third tool on the combination valve.
3. Inspect the fluid level in the master cylinder, filling if needed.
4. Slowly depress the brake pedal and hold it down.
5. Open the left bleeder on the front of the unit. Allow fluid to flow until no air is seen or until the brake pedal bottoms.
6. Close the left bleeder, then slowly release the pedal. Wait 15 seconds.
7. Repeat Steps 4, 5 and 6, including the 15 second wait, until no air is seen in the fluid.
8. Tighten the left internal bleed valve to 5 ft. lbs. (7 Nm).
9. Repeat Steps 3-7 at the right bleeder on the front of the unit.
10. When bleeding of the right port is complete, tighten the right internal bleed valve to 5 ft. lbs. (7 Nm).
11. Remove the 3 special tools.
12. Check the master cylinder fluid level, refilling as necessary.
13. Bleed the individual brake circuits at each wheel.
14. Switch the ignition ON . Use the hand scanner to perform 3 function tests on the system.
15. Carefully test drive the vehicle at moderate speeds; check for proper pedal feel and brake operation. If any problem is noted in feel or function, repeat the entire bleeding procedure.