U-Joints, PS pump, or rack?

[Joe Dirt]

Ok, for about 6 weeks now, I've been noticing this, and would like to fix it now.

When turning, when I get to close to full turn, the truck seems to slightly bind. My other V8 AWD didn't do this at all. The TC is not at fault. CV's and bearings are all brand new. Same binding was there before replacing them...

When returning wheel to center after the turn, from 1/2 turn to 7/8 turn I get a small vibration in the wheel.

About 3 weeks ago, I had to refill some PS fluid, as it was about 1/2" low in the resevoir. I did turn to full turn, shut off and let system bleed overnight. Problem was not remedied.

Sometimes when driving, I get a vibration when driving straight between say 45 and 70. Sometimes I can hear it too.

2-3 times, I've gotten a whining, pretty loud- when moving from whatever speed to nearly stopped. Once whining, the speed of the truck doesn't much matter. I can stop the truck, shut off for 15 minutes, come back and no noise when I drive it again. The time shut off isn't diagnosis, just after parking it went away.

I have zero discernable play in the U-joint between the front axle and the transfer case, and no evidence of leaking or lubricant breakdown from the joint.

There was a minor leak from the front diff, but that was remedied by replacing the CV's/seal. There was still adequate fluid in the diff.

Tires are all brand new and obviously matching.


Thoughts?

PS pump? Rack going south? Maybe a U-joint? I don't think it's a U-joint or it wouldn't exhibit the turning thing, yes?

 

[waskly]

when you give it gas does it go away?

i would say rack....

 

[Joe Dirt]

Not really, but I rarely floor it. Under acceleration though, no, it stays there...

The only thing that really worries me is that whining. Since I always have a camera with me, if it does it again, I'll get a clip of it if I don't fix it first.

 

[gmanpaint]

If the rack goes south, it will blow the seals and there will be a huge mess under the hood.

1) Air in the steering system still. Turn steering wheel lock to lock multiple times with engine running only.

2) The pump itself is going out. This can go south slowly. Good pumps can whine, so it's hard to say if it's bad from a whine.

3) U-joint will just make a clunking thud noise. Your drive shaft will fall off eventually if a cap is off from a failed snap ring, cracking of the cap (losing bearings), or a retainer failed.

4) Binding maybe from a bad hub, bad caliper, bad tie rods, or (hate to say) cracked bearing cap inside the diff, causing the spider gears misalignment with the inner cv shaft.

My guess is the PS pump is going out on you.

 

[OneLever]

You are probably more qualified than me but I'm pretty good boiling things down so here goes nothing:

When turning, when I get to close to full turn, the truck seems to slightly bind

I get a vibration when driving straight between say 45 and 70.

I've gotten a whining.... whatever speed to nearly stopped. I can stop the truck, shut off for 15 minutes, come back and no noise when I drive it again.

There was a minor leak from the front diff

Binding on turn, constant whining, and known leak. Did you flush out the fluid on the front differential and replace? Any contaminants in it?

 

[gmanpaint]

A whine is more indicative of a hydro pressure build up.

A groan/grind is more indicative of metal to metal pressure.

Distinguishing the two noises apart will help on diagnoses.

 

[Joe Dirt]

It's definitely not a metal on metal noise. What's weird is how and when it appeared. I last noticed it when I was on my street driving home. From 25-ish when I heard it over the radio and opened the door to listen, it was a constant (non speed specific for occurrence or pitch) noise. The pitch definitely sounds hydro, not driveline to me. Only after I was slowing down and nearly stopped in the garage did it stop. It doesn't sound like a typical Ford PS pump whining, which is why I'd think failing PS pump. I don't know what in the steering rack would make that noise, unless it is indeed a hydro pressure build up, which makes sense. The thing is that it was a constant whine, but only 3 times for a total of about 10 minutes. It comes and goes with a long time in between occurrences. I think if it was something int the front diff, it would do it all the time.

Since I've done more stop-to-stop wheel turns and poor-man's bleeding of the PS system since it started trying to evacuate air, I think the best thing to try first is replacing the pump. I'd like to flush the PS fluid anyway as mine was a nice chocolate color. Changing the pump would let me do that and try a new pump in the process.

If that pump is failing, could the feeling of "binding" and maybe more appropriate as 'harder to steer' (no popping or chattering, etc.) be increased pressure feedback from the rack from the pump not performing as it should at the ends of the stroke of the rack? I know nothing about racks unless they're on deer or dear.

Thanks guys...

 

[gmanpaint]

Racks are a simple mechanism.

There is not too many things can go wrong with a rack. It is a simple tooth gear rail inside the rack. Another Round gear that rides on top of it, that when turned, it forces the rail side to side, pushing/pulling the rams connected to the inner tie rods. Seals on either side keep the fluid pressure build up inside the unit. The PS pump is just an assist for it. Seals go bad, or the gears go bad from being worn. I guess if a tooth is worn or missing it could cause binding, but normally if that happens it jams solid and when the PS pressure forces it, the seals blow.

Completely off the wall suggestion here, but stranger things have happened. Just something to look for.

A small object can lodge between the brake dust shield and the rotor, causing binding.

A object can be lodged in the control arms rubbing the C/V axle.

The new C/V axle might be bad.

 

[OneLever]

A whine is more indicative of a hydro pressure build up.

The pitch definitely sounds hydro, not driveline to me.

That makes sense. This is from my shop manual.

Condition:
Power Steering System Noise (Whine-Type)

Possible Source:
Aerated fluid.

Action:
PURGE air from system. REFER to Section 211-02. If the noise still exists, REPLACE power steering pump. REFER to Section 211-02.

I think you're on the right track Joe Dirt. One of the things I like about this forum is I'm always learning better ways to recognize and describe problems before they happen to me.

 

[CDW6212R]

You guys have mentioned almost everything and it's in there.

Given the mention of the PS fluid being a little low once, and the color, I'd concentrate on the fluid first. The PS pump is expensive, avoid that. Plus the lines have teflon seals which can be an issue for leaking from installations.

I suggest a basting tube to remove as much PS fluid as possible, and topping it off with the best PS fluid you can get. Find a tiny bottle of PS additive from Lubegard, they make the best ATF additive so I think their PS stuff should be good too.

Hopefully you just have a poor fluid condition, it needs to be really clean. I've used to use Valvoline Synthetic PS fluid, last year I started buying Amsoil's PS fluid. Most parts stores have the Valvoline fluid, try that, and it's not high. Regards,

 

[Joe Dirt]

Don-

It's nasty. I was going to flush it this spring, but probably should do that now. Will basting out the reservoir be enough, or should I evacuate the system totally? How about putting on an in-line PS filter?

Fluid looks like this:

PS- steering didn't get better or worse after the new CV's, old ones had leaky boots though.

Thanks guys...

 

[CDW6212R]

I had found mine a little dirtier than it should be about two years ago. It did make a little noise which got me looking for it. I probably basted out fluid about four times, letting it run between each time. That cleared it up a bunch, and I haven't noticed anymore issues. I also planned to drain it all and swap the fluid, but it was Winter then and I pushed it off. Now almost two years later, you remind me I need to look at it again. LOL, out of sight and mind.

 

[the_aszman]

this wouldn't have anything to do with the whine but have you checked the steering mid shaft ?

the joints in the knuckle are notorious for going bad and will cause a bind like your describing.

the whine sort of sounds like air in the system.it can be a pain in the a&& to bleed the steering system.without a vacume pump it takes me all afternoon to bleed my power steering system with it jacked up on stands.

i just recently replaced a ps pump,rack and pinion with with tie rods,and mid shaft to fix my steering.the rack had a couple of "hard" spots and needed replacing but the mid shaft ended up being my biggest problem.

 

[OneLever]

The shop purge procedure uses a hand pump to create a vacuum with pressure of between 68-85 kPA (20-25 in/Hg) atmospheric pressure is 101 kPA. The vacuum pump can also be used in brake bleeding if I recall correctly. They don't cost much either: Link.

 

[Joe Dirt]

Ok, so I have the pump ordered, new twist tonight.

I was starting the truck to back out of hte garage so I could bring in some firewood. It cranked about 2 seconds. Let off the key, tried again, and it labored, like nearly seized. Like something was holding the belt from turning. Let go, tried to restart, fires up, runs normal. It did that about a month ago once, never did it again.

This PS pump is taking a crap isn't it...

 

[CDW6212R]

I doubt that PS pump would make that symptom. I would very soon though pull the belt and check all of the pulleys and accessories. Now is a great time to replace the three idler pulleys, those bearings are only good for say 100k miles. 75k would be an early failure, and 150k would be fortunate for those. They only cost about $15 each, check around at parts stores and Ford. Some are plastic pulleys, some steel, and some will be different from different sources. Cheap insurance for those bearings, and the belt too.

 

[Joe Dirt]

I did check them all when I replaced the belt about a month ago, and they were all fine, 2 were already replaced. Something stopped the belt from turning though, that was weird...

I guess it could have been something amiss with the starter too though...

 

[CDW6212R]

The worst that usually would happen is an accessory would seize, but the belt would still turn, and squeal. The crank should spin the belt no matter what unless the engine is the problem. So I'm not saying you have engine trouble, but the starting issue shouldn't be related to any accessory. Maybe a spark plug check is in order.

I'm hunting a very rough running problem with my 91 MarkVII, and my worry is that it's a burned valve/seat or plugged injector. As cold as it's been it's no fun right now to work outside.

 

[1AJeremyD]

Even if the a pulley was stuck the belt would still be able to turn. The starter might be going if it seems like there is holding the engine back. Could be a bad spot on the coil windings for the starter. Just a thought....

 

[Joe Dirt]

Yeah, there was no belt squeal, so the starter thing does make sense... Cool- more parts to buy!