Wat problems will incorrect steering box pre-load cause?

Discussion in '40- & 55-Series Tech' started by Rick '79 FJ40, Nov 10, 2005.

  1. Rick '79 FJ40

    Rick '79 FJ40 SILVER Star

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    I have a factory power steering setup on my '79 FJ40, but it seems to be kind of "loose" when you are going down a straight road. I bought the gearbox used and don't know if the PO had changed the preload before I got it.

    I was wondering what changing the preload, either increasing it or decreasing it, would do to the steering. Would a too light preload make it wander or feel like it is loose?

    I have replaced all of the TREs and the rag joint and rebuilt the drag link end and the center arm, so there is virtually no play in anything else in the steering.

    I also have a new OME steering stabilizer.

    Thanks for any help you can give me!
     
  2. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    too much preload would not make it wander, but harder to turn...




    what is your suspension configuration/condition? what is your caster set at?


    what is the condition of the trunion/knuckle bearings on the front axle?



    You are not going to have the same tight steering with this Land Cruiser as you have with you '99 runner...
     
  3. Pin_Head

    Pin_Head

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    Besides making it harder to turn, increasing the preload on a box that has worn out sector shaft bushings can result in cracking the box casting (usually the end cap) when you hit a bump.
     
  4. Rick '79 FJ40

    Rick '79 FJ40 SILVER Star

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    I should have gone into it a little more I guess...

    When I first got the truck, I had the knuckles rebuilt. I am assuming (hopefully correctly) that the guy who did it replaced the bearings and stuff like that. I think i told him to but it's been a year and I can't remember for sure.

    After I first got the steering changed over and had some problems with wander, I had the caster checked and the shop said it was correct, approximately +1. I may need to increase it a bit based on what I've read here, but it shouldn't be terrible the way it is.

    The PO put approximately a 3" lift on it, I'm not sure exactly. It has Rancho springs and probably Rancho bushings on it. It rides hard as hell on bumps, but seems pretty good other than that.

    I am more interested in what too little preload might do, since my steering seems to be too easy instead of too hard. Does anyone have experience with this?

    I may not be able to get it as tight as my 4Runner, but I'd like to get it to the point where I am not "chasing" the road all of the time.

    Thanks!
     
  5. Pin_Head

    Pin_Head

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    There are two kinds of preload on the box. One is the preload on worm gear bearings that is adjusted by removable shims. You don't need to fool with this once it is set. The other is the preload on the sector shaft. This changes the tooth engagement of the sector shaft and worm gear follower, but it is set as a preload value on the worm gear by turning the adjuster screw on the sector shaft end cap. If there is too little preload, it will create a little more backlash in the gears. This should have no effect on causing wandering, but if your truck doesn't track straight it will make it harder to correct. Try adding more caster if it wanders.
     
  6. Horsehead

    Horsehead

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    My '76 is stiff as a board cause of the ROUGH country springs, very aptly named if you ask me. also, larger tires often times make it follow ruts in the road, etc. etc.... I had to install dual stabalizers and the difference is amazing as far as how the wander was decreased...
     
  7. Rick '79 FJ40

    Rick '79 FJ40 SILVER Star

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    Steering Preload

    I think I'm doing a bad job of explaining my problem...

    The truck doesn't really wander, but there is play in the steering wheel when it is centered and the truck is going down the road straight. The steering wheel is extremely easy to turn right and left to a point then it gets harder when you try to turnright or left. I have removed all of the play from the linkage (I think) but this issue is still causing the truck to be difficult to drive. I think the wheels are moving within this play, but it is so easy to turn the steering wheel that I tend to overcorrect and have to turn back the other way. This is what is causing the wander, not the linkage.

    I was hoping that increasing the preload would increase the amount of effort you have to use to turn the truck in this center area of the steering. That may not be it, I may just need to get the box rebuilt, but I wanted to ask about this before I spent the money. Especially if rebuilding isn't what it needs...

    I hope this is a little clearer.

    Thanks for all of the help.
     
  8. Pin_Head

    Pin_Head

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    With proper caster, the truck should track straight, so there is no need to constantly correct.

    Check the play in the box to see if it is OK. About +/- 20 degrees is normal. Have someone rock the wheel back and forth while you look at the end of the sector shaft where the pitman arm bolts on. If the arm doesn't rotate when you rock the wheel 20 degrees, then it might need adjustment. If the shaft end wobbles back and forth before it starts to rotate, the bushings are worn. It is not a good idea to increase the preload on a box with worn bushings. Rebuilding a manual steering box is polishing a turd IMHO. get a PS box.
     
  9. Rick '79 FJ40

    Rick '79 FJ40 SILVER Star

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    Steering Preload


    I agree, but this is a factory PS box that I'm talking about...

    Do you (or anyone) know what it costs to get one of these rebuilt? And who ito get to do it?

    Thanks!
     
  10. trekker

    trekker

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    Are you in Woodstock, GA? I'd talk to Dave ar UrbanLandCruisers in Atlanta. He'll fix you up.
     
  11. Rick '79 FJ40

    Rick '79 FJ40 SILVER Star

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    Steering Box preload


    Yes, I'm in Woodstock. Where are you?

    That's David Dearborn? I've heard of him... I'll check him out.

    Thanks!
     
  12. Pin_Head

    Pin_Head

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    I guess that I should have read it more carefully. The cruiser PS box is the same as the 79-85 mini truck except the main casting is different. All the parts interchange. The PS box has needle bearings on the sector shaft and these to not tend to wear out. You can go ahead and tighten the preload adjsuter as described in the FSM to see if this removes any excess play. I doubt it will as the PS box does not tend to wear as much as other components. Just find where the slop is by having someone rock the wheel back and forth to see what moves that doesn't result in movement of the wheel.
     
  13. Rick '79 FJ40

    Rick '79 FJ40 SILVER Star

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    Well, I figured out what the prolem was with my steering..

    I'm an idiot!

    I was poking around looking for problems this weekend and decided to check the adjustment of the center arm. The adjustment was fine, but I discovered that the bolts holding it onto the frame were so loose they were about to fall out! I'm damn lucky I checked it when I did, or I would have had some SERIOUS problems on the road!

    I tightened the it up (torqued the bolts real good this time) and now it drives like a new truck! I'm excited!

    The thing drives so diffferent that I had to learn how to drive it again...

    Thanks for the help guys!
     
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