I replaced the power steering pump supply line on my 1990 blazer 5.7. I purged the the system to get all of the old power steering fluid out. I replaced the return line and filled up with new fluid,when I start the truck and turn the wheel from side to side, there is a noise coming from the pump.Could this bebecause I did not get all of the old fluid out? I usedValvoline syntec fluid. After I turn off the engine andcheck the fluid level itsreally foamy. Could this be the new fluid mixing with the old?

 

You need to cycle the steering with the engine off and the front wheels off the ground. This will purge all of the air from the pump and steering gear.

Mostlikely the air that was in the new pressure line went straight into the fluid, causing it to foam up and is the source of your noise. If you wait for quite awhile, the air should separate back out and allow for proper bleeding of the system.

 

thanks for the info. what do you mean by proper purging? i followed the instructions with the new supply line. it said to fill up the fluid, disconnect the return line from the pump and cap it. then with the engine running turn the wheels back and forth until the fluid that comes out is clear. then reconnect the return line and refill with new fluid

 

The engine should not be running while you purge the pump and steering gear. The cycling of the steering gear side to side will purge the air out.

The method listed with your new pressure line will work so long as you keep the ps res full. If at any time the pump draws in air, you have to start all over again.

 

so with engine off, cycle side to side until fluid is clear?

 

thanks for the help, that fixed it