Power steering pump and alignment issues

[david85]

Is there any way that a power steering pump could affect a poor return to center when driving in a strait line? This is a problem I've fought with my truck since getting it.

Power boost seems to be fine in both directions when maneuvering near 0 MPH, but it seems that there is a delay when trying to make gentle corrections on the highway. The truck will hold a gradual turn in either direction no matter what the road camber is.

New kingpins on both sides helped a little. Replacing the steering box changed nothing (used). Tires are wearing well and camber is bang on. No play in the steering gear. Hard turns at higher speed are also fine with plenty of power boost felt through the wheel.

The truck will return to center depending on vibrations in the road almost as if friction is being overcome by the shaking (driving over areas with tar patched cracks will do this). Hard to describe. A slight tire shake at certain speeds will also aid in self centering. In some cases a "bump-steer" can happen where I am trying to correct lane tracking and roll over a bump resulting in an over correction with no change in steering wheel position (crossing the thresh hold of a bridge for example).

I feel its really close to where it should be but not quite there yet. Any ideas would be great.

 

[CESMITH]

check the tierod ends closely with the engine runing and someone turning the wheel my 86 was doing the same with less than 6000miles on new ends

 

[Metalmacguyver]

It sounds like your caster is out of adjustment but IDK how that could actually happen.......

 

[Hybrid455]

This is a common complaint with these trucks. Is your truck a 4x2 with a transfer case for low range? It would help me to know what it has for a front end.

 

[david85]

I do have a transfer case, but the front end is the forged I beam stock 2wd setup for a 1986 F250. The truck drove the same before swapping the 4wd E4OD tranny in though.

 

[Hybrid455]

I just wanted to know if it had a 4x4 or 4x2 front end because I would approach each differently. Have you replaced any parts other then the box and the king pins?

 

[david85]

Nope. No idea if the pump is original, but I did replace a seal on it recently since it was leaking from the reservoir.

 

[f-two-fiddy]

Usually, not returning to center is a problem inside the steering box.
Have You adjusted it? To tight f a preload will lead to no return to center.

Prolly time for a new Red Head box.

 

[david85]

This truck always had this problem. Changing the box didn't affect it at all. I did try adjusting the box afterward and simply put the settings back to where they should be.

The replacement box came out of a low miles ranger, but it was still a used one. Seems a little far fetched for both old and new boxes to have the same problem though.

 

[Hybrid455]

Ok. The cause of the problem you are describing can be cumulative. You may have 1 issue and there may be several. CESMITH is on the money. You need to start by checking for looseness in the steering linkage. As he said. Have someone in the truck rock the steering side to side with the engine running and watch for any sideways movement in the tierods and drag link at there studs. When your rocking the steering wheel and looking at tierods only rock the freeplay in the steering wheel. You only want to take up the slack. Its harder to see small movement if you get all crazy rocking it. Also ck the lower steering shaft on the slip joint for movement. Ck the rag joint at the gear as well. It doesn't take much to screw the pooch. Zero tolerance on the side to side movement. Since the King pins have been replaced we can assume they are ok but I have seen king pins fitted too tight. That can cause a poor steering return problems. Check the radius arm bushings and the axle pivot bushings. You can rock the steering harder when looking at them. You want to stress the front end. Some give in the radius arms is normal but if there sliding back and forth in the brackets you need bushings. While I'm thinking about it.... If you need bushings. Everyone always goes loco for polyurethane. Don't do it. Polyurethane has its place but for the everyday driver all they are is noisey squeakin kreakin sob's. Just use good quality MOOG frt end parts and you won't go wrong. Anyway... back on track here. Ck the radius arm brackets sometimes rivets and bolts loosen up. If the radius arms get to shifting around to much your caster is going to be all over the place. The truck may dip and weave when you hit a bump. Check the steering gear adjustment. Ford has a way involved procedure but here's how I do it. Steering straight ahead. Loosen lock nut and screw the adjustment down just till you feel it bottom. Rock the steering and check it again making sure the worm has just bearly bottomed then back it out 1/4 - 1/2 a turn and lock down the lock nut. Make sure your front tires are nice and square. A rounded off cupped tire will make the truck drive like crap. Sorry for the book. There's more but this gives you something to chew on for now.

 

[david85]

Wow thanks, Hybrid455! Tons of info there

The kingpins are perfect. If I have the truck on blocks and pop the tie rods out, the wheels will swing back by gravity and can be pushed with a finger tip. I'm quite confident they are as close to perfect as can be.

All the rivets for the radius arm chassy bracket are good. I had to remove the kingpin and radius arms when it came time to do the kingpins and it seems the rubber mounts are also in very good shape (Likely not factory original). They are not urethane but I did hear of problems with urethane being too stiff and even causing stress cracks in some cases in these trucks.

Based on what you just told me however, its possible my steering box is slightly too tight. I will follow your method and see if it changes anything.

I don't think there is any play in the tie rod or steering shaft, but I will check again. I am thinking of getting an upgraded steering shaft though. Guys here speak highly of an aftermarket replacement that eliminates the rubber joint on the box end of the shaft.

Basically the only complaint is the steering is slightly too stiff near the center. Not enough that you have to fight it with muscle, but enough that you have to hold the wheel turned for a second or two before a slight lane tracking correction takes effect. There is also a lack of "feel" for the truck near the center. There is no force feed back unless going over bumps that seem to loosen it up enough to return all the way to center.

Tires are near new, but I think one of the rims is bent slightly. Been meaning to take a closer look at that. Although I don't think that will affect much.

 

[happyreefer]

I was having a lot of steering issues too. then one day it just stopped steering to the right. install a gear rebuilt by redhead and man this truck steers like it just came off the lot.

it might be that time. I had 185K on my original when she went on me. good luck.

 

[david85]

Steering box checks out. I tried backing it off a little and ended up with play in the steering but still no return to center.

Is it possible for ball the Tie Rod ball joints to be stiff in the strait ahead position? They have always been well greased, but I dunno?

How stiff should they feel? Usually when messing around with the front end, the studs are easy to swivel by hand but thats pretty subjective.

 

[Hybrid455]

It's possible you could have something tight or bent in the linkage. I have seen bent studs. Not very common though. Do you have a great big steering damper on it? I've had those give me steering return problems. The column itself isn't tight is it? If it's a tilt does changing tilt position change the way it feels? Increasing positive caster can help steering return but Ford didn't give us an adjustment on these trucks. It can be accomplished by using aftermarket kits. These kits usually involve eccentrics that are intalled in the front of the radius arm or special radius arm bushings. This would obviously involve a good alignment shop willing to crank up the caster for you.

 

[Black dawg]

hows it act if you kill the motor at speed? ive seen those steering shaft ujoints be tight in the straight ahead pos.