Disconnect the negative battery terminal using an 8 mm wrench. Look for the belt routing sticker on the fan shroud. If it is not there, make a note of the routing before removing the belt. Draw it out or take a picture with your cell phone or camera. Remove the serpentine belt by placing a 16 mm wrench on the automatic tensioner and lifting upward on the wrench. This will move the tensioner away from the belt, thus relieving the pressure, and allow removal of the belt. Do not allow the tensioner to “snap” back quickly, as damage to the tensioner arm may occur.
Changing the power steering pump on a 1990 Chevy Astro van is moderately challenging due to the complexity of the procedure. A special tool is needed to extract the power steering pulley. The majority of power steering pump failures is due to either a leaking front seal or contaminated or damaged pressure relief valve. Changing the power steering fluid when signs of contamination are present extends the service life of the pump.
- Drain pan
- Power steering fluid
- Power steering pump pulley remover tool (most install as well)
- Set of sockets
- Common flat-head screwdriver
- Set of wrenches
- Large adjustable wrench
- Torque wrench
Remove the pump pulley with a suitable removal tool. Use a wrench to hold the center shaft and the large adjustable wrench to turn the extractor nut counter-clockwise to pull off the pulley as the clamps grasp it. Place the drain pan under the pump.
Remove the pump retaining bolts to mounting bracket using a socket. Position the pump for easy access to the rear of the pump. Remove the low-pressure hose by loosening the hose clamp with a flat-head screwdriver. Remove the high-pressure hose with the use of a wrench. Drain all the power steering fluid into the drain pan. Remove the pump from the van.
Position the new pump and uncap the ports. Install the high- and low-pressure hoses. Position the pump on the mounting bracket and install the bolts. Torque the retaining bolts to 37 foot-pounds using the torque wrench.
Install the pump pulley using the same tool as used for the extraction by removing the clamps used for pulling. The large nut will push the pulley on. To make it a little easier to install the pulley, pull the oil dipstick and use your finger to rub off some oil on the pump shaft and on the nose of the pulley. Hold the center bolt with a wrench and with the use of the large adjustable wrench, turn the nut clockwise to install the pulley.
Confirm the nose of the pulley is flush with the end of the pump shaft when installing the pulley. If not, the belt will be misaligned and accelerate the wear on the belt. Install the serpentine belt as illustrated on the fan shroud. Place the 16 mm wrench on the bolt in the center of the tensioner pulley and lift the tensioner. Place the belt under the tensioner pulley and relax the tension on the tensioner.
Fill the pump with approved power steering fluid. Start the engine and rotate the steering wheel lock to lock in each direction slowly to evacuate the air from the system. Continue until the pump is quiet. Shut the engine off and top off the power steering reservoir. Replace the cap on the reservoir.