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! I bleed the brakes starting with the right rear caliper then the front left. Then did the left rear then the right front calipers. I followed the bleeding procidures that wilwood gave me with their calipers
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As for gravity bleeding.... I highly doubt that that will fix anything nor work. Unless it was a joke.
Brake and Front End Magazine wrote:SELLING SERVICES
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Bleeding ABS Brakes After Component Replacement
By Larry Carley
Bleeding the brakes after brake components have been replaced is a step you don’t want to skip if you want a firm brake pedal. Air trapped in the lines, calipers or wheel cylinders will make the pedal feel soft and spongy. Air is compressible, so when the brakes are applied any air bubbles in the system must first be compressed before the hydraulic fluid will transmit pressure to apply the brakes.
As a rule, the brake circuits on most vehicles with anti-lock brakes can be bled in the usual manner — provided no air has gotten into the ABS modulator assembly. If the only components you replaced were downstream of the modulator (calipers, wheel cylinders, brake hoses or lines), chances are normal bleeding procedures will clear the lines of any unwanted air.
Brakes can be bled manually, with a power bleeder, injector tool or vacuum bleeder. It doesn’t make any difference which method you use as long as all the lines and components are flushed with enough fluid to remove any trapped air bubbles or air pockets.
The most common bleeding procedure is to bleed the brake furthest from the master cylinder first, then bleed the other brake that shares the same hydraulic circuit (which may be the other rear brake on a rear-wheel drive car or truck, or the opposite front brake on a front-wheel drive car or minivan). After these have been bled, you then bleed the other brake circuit starting with the furthest brake from the master cylinder.
Always refer to the vehicle manufacturer’s recommended bleeding sequence as this may vary from one application to another depending on how the system is configured.
NOT SO FAST
But what if you replaced the master cylinder, a brake line or valve ahead of the ABS modulator? Or, what if you had to replace the modulator or high pressure accumulator? Now you have a more difficult job ahead of you.
Air can be very difficult to remove from an ABS modulator assembly because of all the nooks and crannies inside the unit. The modulator may have eight to 10, or more, ABS/traction control solenoid valves, plus various check valves and dead-end ports. Some ABS modulators have special bleed screws to help you vent the trapped air when bleeding the system. Others do not and require the use of a scan tool to cycle the ABS solenoids while you bleed the system.
To better understand what may be required, let’s look at some bleeding procedures for some common General Motors ABS systems....
...DELPHI DBC-7 ABS
Introduced on 1999 Buick Regal and Century, and Chevrolet Tracker, the Delphi Brake Control (DBC) 7 ABS system is the successor to the Delco ABS-VI system. It replaced ABS-VI in 2000 on Chevrolet Impala, Monte Carlo, Malibu, Cavalier and Venture, Pontiac Sunfire and Montana, and Oldsmobile Cutlass and Silhouette.
Unlike the earlier ABS-VI system, DBC-7 does not use motor driven plungers to cycle pressure in the brake lines. It uses solenoids like most other ABS systems. The Brake Pressure Modulator Valve has one inlet (apply) valve and one outlet (release) valve for each brake channel, plus two accumulators (one for each brake circuit). So the BPMV contains a total of six ABS valves for three channel system applications, eight ABS valves for four channel systems, or 10 ABS valves if the vehicle has TCS traction control. The inlet valves are normally open, and the outlet valves are normally closed. The solenoid for each valve is energized when the EBCM provides a ground to complete the circuit.
The GM passenger car applications are all four-channel ABS systems, so each of the four BPMV outlets is connected to the brake line for a separate wheel. The lines are color coded for identification:
• Left rear is purple;
• Right rear is yellow;
• Left front is red; and
• Right front is green.
DBC-7 BLEEDING PROCEDURES
Normal bleeding procedures can be used to bleed the individual brake lines provided no air has entered the ABS modulator. But if air has entered the modulator, the system will have to be bled using a pressure bleeder and scan tool:
Connect the pressure bleeder to the master cylinder reservoir.
Turn the ignition on.
With bleeder screws closed, pressurize the system to 35 psi.
Select the “Automatic Bleed Procedure” on the scan tool. The scan tool will then energize and cycle the ABS solenoids in the BPMV for one minute.
After this, the scan tool will instruct you to bleed each wheel. During this step, the pump runs and the respective release valve cycles for one minute. This is repeated for each wheel. Finally, the scan tool performs a final 20 second cycling of the ABS solenoids to purge any remaining air.
Relieve pressure at the bleed tool and remove it from the master cylinder. Then check pedal height and feel to make sure all the air has been removed and the pedal is firm.