My power steering fluid is bubbling out of the cap after I drive on the highway for while. When I get off the highway on the back roads I can here it whining especially when I turn the wheel all the way to the side, than after it cools down its fine. I checked the fluid level and it was just a little low not much so I added some. I haven`t had any work done on it so it shouldn't be an air in the line issue. I`m puzzled ?? Any help would be appreciated.

 

There is air in the system from running low on fluid. The pressure line is prob leaking or the rack could be leaking into the boots. With the engine idling and the fluid full slowly turn the wheel to one direction and turn the engine off. Let the truck sit until all of the bubbles come out of the fluid. Fill the reservoir if needed and start it back up and steer all the way to the other direction, shut it off and let it sit again until the fluid has no more bubbles. Rinse and repeat until there is no air in the fluid. If you dont shut the engine off then aerated fluid is being pumped so the air can't bleed out.

 

Is there another, more direct, way of bleeding the power steering system? I've followed the above procedure probably a dozen times on each side and haven't gotten much improvement. I'm fairly certain there is air in the system as I didn't have the issue until after I replaced the broken low pressure line going from the ps pump to the cooler in the front of the truck. Raised the truck on stands and turned the wheels by hand (actually grabbing the tire and turning the rack that way) with the engine off at which time I heard fluid sloshing from what I believe is the rack. Is there a bleeder valve on the factory rack? Would loosening the high pressure line and bleeding that way help? Tried looking for a more detailed procedure in the forum and couldn't find anything easily.

Hoping someone can assist. Thanks!

 

OTC makes a tool that attached to a vacuum pump and seals the reservoir so you can pull a vacuum on the PS system. The vacuum will draw any air out. The tool number is 211-265 and it's around $80 IIRC. But the method I described above works fine, it just takes longer. Moving the wheels with the engine off can actually draw more air into the rack. What are your symptoms? Can you see aerated fluid in the reservoir while the engine is running?