Pressure Bleeding

WARNING: This page does not describe the selected car, but rather 30 other vehicles, including the 1998 Pontiac Trans Sport, 1998 Oldsmobile Silhouette, 1998 Oldsmobile Bravada, 1998 GMC Yukon, and 1998 GMC Suburban. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Air tends to cling to caliper walls. When bleeding vehicles with disc brakes, lightly tap caliper to help remove air.

WARNING: DO NOT use rigid clamp to position hold-off valve stem. This may damage valve assembly, causing brake failure.

Retain hold-off valve stem of combination valve using Valve Retainer (J-23709) on Commercial Van, or (J-39177) on all other models. See Fig 1. This allows brake fluid to flow through combination valve and entire system during bleeding.
Clean master cylinder cap and surrounding area. Remove cap. With pressure tank at least 2/3 full, connect pressure bleeder to master cylinder with adapters. Attach bleeder hose to right rear bleeder valve.
NOTE: On vehicles with 4WAL, if brake pressure modulator valve was replaced, or is suspected to have air trapped inside, it must be bled next. See appropriate ANTI-LOCK article.
Place other end of hose in glass jar partially filled with brake fluid so end of hose is submerged in fluid. Open release valve on pressure bleeder. Set pressure bleeder to 20-25 psi (1.4-1.8 kg/cm² ) or pressure specified by equipment manufacturer.
Open bleeder screw 3/4 - 1 turn and note fluid flow. Close bleeder screw when no air bubbles are present in fluid flow. Repeat procedure on left rear, right front, and left front wheels in this order.
Check brake pedal operation. Remove pressure bleeder. Remove valve retainer from hold-off valve. Refill master cylinder reservoir, if necessary.

Fig 1: Positioning Hold-Off Valve On Combination Valve (Typical)

Courtesy of GENERAL MOTORS CORP.