Just Replaced Faulty Power Steering Pump... Created More Problems

Discussion in 'SN95 4.6L Mustang Tech' started by CWSpartan, Oct 9, 2017.

  1. Hey guys over the weekend I replaced my failing power steering pump on my 2004 gt 5 speed. The pump I installed is a remanufactured part from autozone. When I put it on I drained the fluid from the system, replaced it with merc 5 ATF and turned the wheels lock to lock to get all of the air out of the lines. I used a hand operated vacuum pump to encourage some of the air to come out. When I started the car up (still on the jack stands) the pump started whining like it still had air running through it. Whenever I pushed the brake is made a scraping noise like it was causing strain on the pump. When I turned it off and tried to work air out of the system again, I noticed that moving the wheel would cause the level of fluid in the reserve rose, and the hand pump was no longer pulling a vacuum (I could hear air bubbling through the lines). The odd thing about this air coming in to the lines is that no fluid is leaking out anywhere, and whenever I start the car the fluid drops to a normal level. I think there might be a problem with the hydro boost system but I'm not sure. Any ideas?
  2. I will qualify my next statement by saying that I don't have a Mustang your year. That aside:

    I don't think that you should be using a vacuum pump of ANY KIND to help pull air from the PS system. All of those connections are sealed by o-rings and teflon backing. They "work" by having fluid pressure act on them in order to inflate and fill the cavity. You are pulling air through those seals by creating negative pressure in the power steering system.

    Ditch the vacuum pump, re-fill the reservoir, start the motor, and run the steering lock to lock while an additional person ensures that the pump reservoir maintains an adequate fluid level.

    Do not re-apply the vacuum pump or you will undo the system bleed.

    The o-rings are not designed to resist pressure travelling in that direction. Think of it like a pressure seal on an aircraft. When the aircraft is pressurized, the seals inflate against the mating surfaces to create the seal.
  3. The reservoir is currently filled to the right level. Should I drain the system again? I should note that the fluid I drained the first time was clean and I saw no debris in the reservoir.
  4. Don't reuse fluid.
  5. FWIIW, I'm not so negative on the use of vacuum to help bleed power steering and actually think it's a positive idea. It would seem to me that IF the problem is there is still air in the system that falling back to more "standard" methods should resolve it without a need to refill.

    I KNOW from experience that IF there's any air in the system that allowing the air to become pumped through out the system will only make the bubbles smaller and more difficult to remove. Therefore one method change is to STOP the motor just as soon as bubbles are seen. Allow the bubble to clear. Wash, rinse, and repeat.

    I also know from experience that it can take several cycles to fully bleed the air. It can take quite some time depending upon just how small and far the bubbles are through the system.

    Suggest going back to double check your work. Look for any bent or kinked lines.

    Just so that we understand, what was the reason to replace the PS pump in the first place?
  6. I've seen many re-man PS pumps bad out of the box over the years...
    nosshane and 74stang2togo like this.
  7. I didn't think that using a vacuum pump would be an issue. If I recall correctly the Ford service manual even details using one to evacuate the air.

    I'm not entirely sure the problem was with the power steering pump in the first place. I've noticed since I bought the care in June that my steering becomes difficult at low speeds (like when I'm parking). I still have power steering at this point, but it is greatly reduced to the point that I have to use two hands and some effort to move the wheel. I know this might not be the source of the problem, but it was my best guess.

    Also in response to Noobz347 I did not reuse fluid and did not plan to.
    #7 CWSpartan, Oct 10, 2017
    Last edited: Oct 10, 2017
  8. I'm confused. Is the main complaint excessive steering effort at slow speeds? Was the complaint present before replacing the PS pump? How did the symptom change after replacing the pump.

    FWIIW, excessive steering turning effort could be cause by bad ball joints.
  9. Looking back that was very unclear on my part...

    So the initial problem was the difficult steering at low speed. I thought the problem could be with power steering pump since this was an intermittent issue that got worse the more I was on the brakes.

    I replaced the pump on Sunday, and since the whining has started I left the car on the jack stands. So to be honest I have no idea if the initial steering issue has been fixed.
  10. Ok I have an update.

    There is fluid on the passenger side rack boot. This leads me to believe that there is a leak somewhere in the lines or on one of the seals. I'm going to try to track down the source of the fluid.

    I'll keep you guys posted. If anyone has any suggestions let me know.
  11. Air in the system, debris in the system or faulty parts. I'm on my 4th reman pump. They don't like rpm. :)
    nosshane likes this.
  12. So a lot has happened over the weekend I'll try to recap everything.

    The first thing I did was drain the system of fluid and flush a full quart of additional fluid through it. That didn't help so I moved on to the next possible solution. I realized at some point that I forgot to replace the teflon seal on the output line from the pump. I decided that since I had to replace that seal I might as well put the old pump back on to see if the new one was bad out of the box. When I turned the car on it was still whining so the problem wasn't with either the seal or the new pump.

    I decided that whatever the initial problem was I had simply made it worse by trying to replace the pump. I looked for anywhere there was fluid throughout the steering system to see if I could find a leak anywhere. Once again, I noticed fresh fluid on the passenger side rack boot. When I loosened the boot, a good 3 tablespoons of steering fluid poured out. I had someone turn the wheel while I looked at the inside of the rack near the inner tie rod. Every time the wheel is turned right, fluid is squeezed out of that end of the rack, and when it is moved left it sucks air into the rack.

    So in the end it looks like the seal was failing on that side of the rack, which was probably the source of my initial steering problem. I guess the negative pressure from the vacuum pump or draining the system the first time caused the seal to totally fail, which allowed air into the system and caused the pump to whine.

    I ordered a remanned rack from Motorcraft which should be here by Tuesday. I also noticed that the rubber boots on both of my balljoints are pretty much shredded, so I decided to replace those as well. They should be here by Tuesday too.

    Once all of this is on the car I'll let you know if the whining and the steering difficulty are fixed. Thanks for all your help everyone!
    Neuron likes this.
  13. Alright everyone final update.

    I pulled the old rack and the old lower control arms since I couldn't get my hands on the tool to pull the ball joints out. There wasn't anything wrong with the rack other than the dead seal. Let me just tell you though, the ball joints were in horrible shape. I'm guessing they were the reason I couldn't steer. I probably broke the rack seal when I pulled the vacuum on the power steering system.

    I installed everything over the weekend and had an alignment done yesterday. It runs flawlessly and I can finally maneuver it into a parking space with ease. Thanks for all the help guys I really appreciate it!
  14. Always loved a happy ending, thanks for the update. Scary thing when a ball joint lets loose while driving!