I've got a pulsation in the steering on one of my 98 Explorers. I noticed just a slight bit of it in the steering when I was driving the vehicle. I'd raised up the front end to check for damage to ball joints, bearings, cv joints etc. because my wife had an accident and spun the vehicle. I found nothing wrong so I went to check the steering to see if I could duplicate the deep groaning type sound we get, especially when turning right. It felt smooth with the engine running so I decided to start the engine to see if the power steering had any effect at all. When I did the steering became twitch and you could feel the pulsation through the steering wheel and see it in the front wheels. I tried shutting it down and moving the wheel several times stop to stop to see if I could bleed off any air that might be trapped in the system. Then I started the engine and did the same thing. At that point the problem became worse. Any ideas what I should try? The problem could be associated with the damage from when she spun the explorer but I doubt it because it didn't seem to show up for quite some time after the accident, the groaning, rough feel in the front showed up immediately. Just to give you a little background she was traveling at about 10 -15 mph in 1st gear in 4 low on a snow covered road. She hit some ice and spun about 270 degrees hitting the rear left on a rock cliff. The body shop did an alignment and said everything was fine that it was cosmetic damage only, rear quarter panel, hatch etc. I have my doubts though because a week after she started driving it again one of the transmission return lines broke and when I inspected it there was evidence of it being scraped across something, large rock maybe. My wife said the front end may have gotten caught on something she doesn't know for sure. Possibly as a result I'm thinking she's damaged the bearings, spindle, or something else. I'd like to get the steering problem fixed before I tackle the rest of the problem. I thought it could have been the rack but it seems to be ok and we aren't losing any fluid. We've taken it to a couple of shops and they just tell us that they all get this way when they get old and not to worry about it (obviously not a good idea). Thanks in advance for any ideas you might have.

John

 

John, I think that you're on the right track...I think that you do have air in your power steering system. Every time - and I mean every time - I raise the front end and turn the wheels manually with the engine off (like when doing a brake job), I get the same pulsation. A little p/s fluid comes out of the pinhole in the cap, and air gets in the system.

When I first start driving the truck after getting it off the jacks, the steering wheel vibrates violently, especially during low speed turns. It sounds like the whole front end is about to shake apart. However, as I continue driving, the magnitude of the vibration lessens, and 20 or 30 miles (maybe 30-45 minutes) later, it's totally gone.

So drive it for an hour or so, and if it doesn't go away, then it's probably something else. Good luck, and let us know if that does the trick!

Kevin

 

Driving the Explorer for a while did seem to get rid of the vibration (pulsation) in the wheel. I've still got some problems however. There's still a loud groaning noise when making turns, for a while it was mainly to the right, now it seems that it's mainly when making tighter left turns. When it was happening while making left turns I thought the noise was coming from the left side only. Then I had someone else drive the truck while I road in the passenger seat and the noise is just as bad on that side. I got out and had them turn the wheel while I got down beside each of the front wheels and listened and the noise is equal on both sides. At a certain point in the wheel travel there's still a noticeable pulsation and rough spot in the steering. I checked the power steering fluid and it's full of metallic shavings. At this point I'm thinking the steering rack is bad in it. A complete rack from NAPA isn't too expensive for the Explorer and this 98 has 160,000 miles on it plus the accident so I'm thinking about replacing the rack. I don't know if I should replace the pump as well while I'm at it due to all the debris in the power steering fluid or just flush it out well and see what happens.
John

 

Sounds like your main problem may be the pump. The pulsing could be do to a lack of pressure the pump is putting out to the rack.

I would replace the pump and install an inline filter on the return line to the pump to catch any shavings that may still be in the system.