HEAVY STEERING - Bubbles in Power Steering Reservoir - Replaced Low Pressure Hoses. What's Next?

[jonheld]

Something else I want to mention--the steering feels too heavy to me - definitely heavier than my '93 LC I had before this '97.

Heavy steering is usually the result of too much caster correction.
Personally, I prefer the heavy feel since I put on the DVS arms. I was able to zero out toe which lightened the steering a bit while still maintaining good road manners and strong return to center.
I would suggest getting the truck on a rack and check the caster and toe.

Also, the "notch" in the straight ahead position indicates worn knuckle bearings.

 

[harrydunn]

Appreciate the input. Good thinking on the on the caster correction but this is a stock height rig. No correction bushings or brackets. Even on the worn original springs it was super heavy to steer--I installed stock-height springs a couple of months ago, however. May be on to something with the toe. I'll get it in for a look this wknd. Yah, I may do the trunnions this winter... not sure why the PO was in that far with the axle rebuild and did not do trunnions. Thanks.

 

[jonheld]

Appreciate the input. Good thinking on the on the caster correction but this is a stock height rig. No correction bushings or brackets. Even on the worn original springs it was super heavy to steer--I installed stock-height springs a couple of months ago, however. May be on to something with the toe. I'll get it in for a look this wknd. Yah, I may do the trunnions this winter... not sure why the PO was in that far with the axle rebuild and did not do trunnions. Thanks.

That makes sense. The more "sag" the front springs have, the greater the caster. As you lift the front, the caster decreases, hence the need for caster correction after a lift is installed.

 

[harrydunn]

Hmmm, I'm going to check the steering box preload tonight. Screw looks to never have been turned in as there are plenty of threads showing, but I may back it off 1-turn to see if there is any discerable difference.

 

[harrydunn]

Did I find the Smoking Gun? Unsure if this would be enough for overly heavy steering but check this out. I pulled out the PO's extensive notes on his own maintenance history (best I've ever seen). He did indeed replace the trunnion bearings in 2021. Started reading further and there it was:

"0.1mm-shimmed to 15 lb/ft preload for larger tires"

I know the FSM states up to 9.9 lb/ft (which isn't always followed obviously)

It's got stock size KO2's on it still. He did not get around to slapping larger tires on it before he decided to sell it. What do you think? New trunnion bearings are not even 2 years old and there's a binding spot in the middle of the steering on both knuckles as mentiond earlier. Not terrible but it's there by hand when you've got the drag link and TRE's disconnected.

Would 5 lbs of extra preload wear that into them in just 2 years and 10,000 miles or so? I've done several FZJ80 axle jobs so not a big deal for me to get in there and check things out one weekend.

OR…do I just pop the upper trunnion cap off, remove the .1mm, slip a .2mm in there, button it up, see how it feels? I know you can’t measure preload by doing it that quick way, but if he’s getting 15 lbs with a .1mm shim, that’s a good starting point to work from.

Thanks!

 

[baldilocks]

If you can feel a detent/binding when you swing the knuckle around the trunnion bearings then I’d say she needs to be torn down for a visual evaluation and possible bearing replacement.

The thicker shim is most likely needed but only after you’ve confirmed the installation of good parts.

 

[himhj60]

 

[himhj60]

I repaired all the pumps and gears, but in the end this was the cause of the heavy steering.

 

[harrydunn]

Yah that’s my thinking too. Trunnions already somewhat trashed. If I can feel a detent turning the knuckles by hand with the wheels/tires on, it should be exponentially more difficult to turn through that detent without the mass of the tires helping. I’ll pop them off, and drag link, TRE’s, and give it a go.

If you can feel a detent/binding when you swing the knuckle around the trunnion bearings then I’d say she needs to be torn down for a visual evaluation and possible bearing replacement.

The thicker shim is most likely needed but only after you’ve confirmed the installation of good parts.

 

[harrydunn]

Interesting. I’ll take a look.

I repaired all the pumps and gears, but in the end this was the cause of the heavy steering.

 

[harrydunn]

Reached out to the previous owner. May as well ask him if he recalls what factory shims it had when he did the trunnions last year. Can baseline things that way. Should have thought of that sooner.