Mopar 4798158AB Power Brake Booster

Removal steps 1. Park on level ground, chock wheels, set the parking brake and wear eye protection and gloves. 2. Depress the brake pedal several times to reduce vacuum assist, then disconnect the negative battery cable. 3. Remove or protect the brake fluid reservoir cap and cover the reservoir to keep contamination out. 4. Support the master cylinder so brake lines are not stressed; if the master cylinder must be loosened, plug or cap the brake lines to prevent fluid loss. 5. Disconnect the booster vacuum hose and any electrical connectors or vacuum switches (typically at or near the booster); note or label connectors for reassembly. 6. From inside the vehicle, access the brake pedal area and remove the retaining pin/clip or fastener that connects the booster pushrod clevis to the brake pedal. 7. From the engine compartment, loosen and remove the booster mounting nuts on the firewall (mounting method varies by design); hold the booster while removing fasteners to prevent it from falling. 8. Carefully withdraw the booster straight out from the firewall, feeding the pushrod through the pedal area and avoiding damage to surrounding components. 9. Inspect the booster mounting gasket, firewall grommet, vacuum hose, and check valve for wear or damage and set old hardware aside for comparison. Installation steps 1. Compare the new booster to the removed unit and transfer any reusable check valve, grommets, or brackets if required; replace worn seals or hardware. 2. Position the booster at the firewall and feed the pushrod through to the pedal area, aligning the booster mounting studs/holes without forcing it. 3. Install the mounting nuts and snug them evenly to seat the booster against the firewall (do not apply unspecified torque values). 4. Reconnect the pushrod clevis to the brake pedal and secure with the original retaining pin/clip or specified fastener; confirm the pedal connection moves freely. 5. Reinstall or secure the master cylinder to the booster, ensuring brake lines are not twisted or strained; if lines were opened, bench-bleed the master cylinder and then prepare for system bleeding. 6. Reconnect the vacuum hose (ensuring check valve orientation as marked) and any electrical connectors previously removed. 7. Reconnect the negative battery cable. 8. Check brake fluid level and top as necessary, start the engine and verify vacuum assist operation (pedal feel should change when engine starts) and check for audible vacuum leaks or warning lights. 9. Bleed the brake system as required if the hydraulic circuit was opened, then perform a cautious low-speed road test to confirm firm pedal feel and proper braking. Repair tip: Photograph and label connections during removal, replace worn rubber grommets and the vacuum check valve while installing, and avoid getting brake fluid on painted surfaces.