Kia 5911038006 Brake Booster Assembly

For detailed photographs of the brake system, inspect the brakes every time the wheels are removed or whenever a defect is suspected. Symptoms indicating a potential brake system defect include the vehicle pulling to one side when the brake pedal is depressed, squealing or dragging noises when applied, excessive brake pedal travel, pulsating pedal, or brake fluid leaks, typically onto the inside of the tire or wheel. Begin by loosening the wheel lug nuts, raising the vehicle securely on jackstands, and removing the wheels. In disc brakes, each caliper contains two pads (outer and inner) that are visible with the wheels removed. Check the pad thickness by looking at each end of the caliper and through the inspection window; if the lining material is less than the specified thickness, replace the pads. If the thickness is difficult to determine, remove the caliper(s) and pads for further inspection, cleaning them with brake cleaner and re-measuring. Measure the disc thickness with a micrometer; if any disc is thinner than the specified minimum, replace it, and check for scoring, gouging, or burned spots, which may require resurfacing. Before reinstalling the wheels, check all brake lines and hoses for damage, wear, or leakage, ensuring they are clear of sharp edges and moving parts. For rear drum brakes, ensure the parking brake is off, remove screws around the drum, and tap the outside with a rubber mallet to loosen it. Clean the brake assembly with brake system cleaner, noting the lining thickness on the brake shoes; replace them if worn to within 1/16-inch of the rivets or if cracked or glazed. Ensure all springs are connected and check for fluid leakage from the wheel cylinder. Wipe the inside of the drum with a clean rag and check for cracks or imperfections that may require resurfacing. Repeat for the remaining wheel, and if all parts are in good condition, reinstall the brake drums and wheels. To check the brake booster, sit in the driver's seat and perform a series of tests: with the brake fully depressed, start the engine and observe if the pedal moves down slightly; with the engine running, depress the brake pedal several times to ensure the travel distance remains unchanged; then, with the engine off, hold the pedal for about 30 seconds to check for sinking or rising. Finally, check the parking brake by parking on a steep hill with the brake set; if it cannot prevent rolling, it requires attention.

In order to do an operating check, engage the service brake apply the brake pedal a few times with the engine switch off but the gap between the brake pedal pressure should remain the same. Next, manipulate the pedal and start the engine; if the pedal slightly descends, operation is typical. Required for an air-tightness check, start the engine and run it for a minute or two before shutting it off, following with application of the brake pedal several times; if the application pressure decreases each time and the brake pedal depresses less, the booster is airtight. Subsequently, with the engine on, engage the brake pedal and shut off the engine with the brake pedal pressed; when this is done, check that the needle on the pedal reserve travel does not move after 30 seconds, then this will be an indication that the booster is airtight. When disconnecting power brake booster units it is important not to dismantle since the units are positively complicated and require intricate tools. First of all, start with the dismantle of the brake master cylinder and, depending on the specific car model, it may be easy to completely discard the crossover brake lines that intersect in front of the master cylinder. Caution and detaching the vacuum hose from brake booster, then pardon the brake pedal return spring at the top of brake pedal and removing the brake booster clevis pin retaining clip and the pin. You then undo the four nuts and bolts that are securing the brake booster on the firewall, and pull the booster straight backward till the studs are out of holes. For installation reverse the following removal procedures, and then tighten the booster mounting nuts to the prescribed torque. The next components to fit are the master cylinder and the brake hoses; when fitting the master cylinder, set the brake pedal height and freeplay and bleed the brake system.