“jumpy” Steering And Alignment

‘75 cj5. I recently replaced the tie rod and drag link, so, had an alignment done. Except for the left front camber( 0.4), all is good. The steering over 50ish, is still jumpy/sloppy. Ive been tightening the steering box incrementally over the last few days as well, with a tiny bit of success. In total, I’ve adjusted maybe 1/2 a turn. Is this just a product of a short wheelbase ? Tire pressure on my 30x9.5 km3’s is now 30 psi, up from 25, which helped a bit. The “jumpy” part is in turning, where it feels like it wants to turn too much. Any thoughts ?

 

Sorry if I'm brusque - I've covered this so many times in the past.

Went through this with a friend who bought a used '72 Jeep and found it hard to control. We took the springs off and found a caster shim in one side. Removed that shim and it drove fine.

You should have the same and adequate caster on both wheels.

Don't adjust the steering gear in the Jeep. The TSM tells you emphatically not to do that. There are steps to follow before you adjust the gear mesh (screw on top). Skipping those steps can be dangerous and/or damaging to the gear.

 

Not at all, I’m thick skinned. With no shims, apparently I’m within spec, but to my question. Is a short wheelbase something which would make it feel jumpy ?

 

No not jumpy. They drive pretty decent in a straight line when everything is in order.

Things that might make it jumpy:

• Too quick of a steering gear ratio. Swap in a box with more turns lock-to-lock to fix this.
• Slop in the system somewhere. Have someone sit in the Jeep and turn the steering wheel back and forth while you watch every steering component for slop under the Jeep. Fix what's bad.
  
• Toe setting not correct. Not enough toe-in can cause twitchy steering. You can check the toe yourself with a tape measure.
  
• Not enough caster. More caster provides better directional stability. 5-7 degrees is ideal. This can be adjusted with angled caster shims between the spring and axle housing.

Taking it to a reputable alignment shop and getting a print out and inspection would be a good place to start.

 

All good thoughts. I think I can delete a few of them. I have a new tie rod and drag link, alignment was yesterday, all is now good except the afore mentioned camber. The guy I’ve been going to for nearly 10 years said there wasn’t anything bad in front end, so, what’s is this sorcery about steering box, of which you speak? That sounds like something that could be. I’ve always thought it was way too easy to steer

 

You can adjust the steering gear, but the TSM tells you to do it on the bench, and in a specific order. RTFM. Read any '70s TSM for the procedure.

This is from the manual steering gear chapter in the '79 TSM free to read and download on the Tom Collins site:



The screw is the "overcenter drag torque," essentially the mesh between the pitman arm gear and the worm.

The warning gets more emphatic as the years go by. That screw must be very tempting. Power steering chapter says the same thing. Makes sense if you think about it mechanically.

The TSMs get more detailed as the years go by; I'd advise following the later manual if what your working on does not change.

 

A worn steering gear will make the steering sloppy. Sloppy and jumpy are not the same.

Going down a straight and level road, the Jeep should continue straight ahead without correction. If the toe is off, it can pick a new direction - that's often called "darty." Another way it can be darty is with too little caster. The caster keeps the wheels pointing straight ahead, and provides the force to return to center when you let go of the wheel. If you drive in a small circle, let go of the wheel, the Jeep should return to straight ahead on its own.

Think of Easy Rider. There is a scene with a few minutes of hands-off riding. The long forks of choppers make like 45 or 60 degrees of caster - that's why they are so stable. Great on the highway but hard to maneuver at slow speed.



The factory spec is 3 degrees positive. It's in the TSM - again, RTFM. If you have 0.4 degrees, that's basically zero caster. One would expect jumpy. One would also expect "light" steering, since there is no caster to work against.

Did you get the printout from the alignment shop? You should have - it's part of the procedure. Post it up here.

 

I wasn’t clear. Camber is .4. Caster left/right is 2.7 and 2.5 respectively

 

Your Jeep could stand more caster. Most folks with around 5 degrees find the vehicle tracks very well. 2 or 2 1/2 degree wedge shims would probably help, provided your steering box is in good shape and adjusted properly.
-Donny

 

Caster is not positive enough despite the factory calling for only about 3 degrees positive. Increase that to 5-7 degrees positive and you will notice a huge difference in how well it tracks. I’d go 2 1/2 to 3 degree shims. Looking at camber you may experience a little bit of a pull to the right as well. I’d look for some adjusters to change left side camber to better match right side but right now that is the lesser issue. Also, get that steering gear adjusted correctly or replaced before you start having other issues. Like Timgr has posted correctly, there are very specific procedures for adjusting a Saginaw gear and that external adjustment is the last one that gets made.

 

x3, The factory spec at around 3 degrees would likely work fairly well when the jeep was new and all parts of the steering, suspension, factory size and bias ply stiff tires and so on were all brand new with zero wear on them.
However as all the parts here and there begin to wear a little the total sum will Slowey start to add up to a gradually increasingly more sloppy (or darty as you describe) steering feel. By adding a little more positive caster will help to force the issue of straight ahead tracking, making up for the slight loss of the drivability because of the wearing in of of the steering system. Just exactly as timgr pointed out referring to to the easy rider chopper bike with large amount's of caster keeping the bike pointed straight ahead with practially no input from the driver.

 

I’m on board. Looking for shims as we speak

 

I bet she will drive a lot better.

 

Ok, so, i got the shims. Which way do i face them to help my issue. Yes, you are welcome to snicker at my ignorance

 

Thick part faces forward to tilt the steering axis back at the top.

 

On my 72 CJ5, I had wandering, and hard to return to center after a turn. All front end parts new including gearbox. Adjusting the gearbox a turn here and there is IMO a bad idea as you most likely had preload on it and would be hard if not impossible to feel any difference other than binding until you drove it. I had a 4 corner alignment and put in 6 degree steel shims and now it goes down the road very solid and feels good at all speeds up to around 60 is as fast as I want to go. I think your biggest benefit will be to get the correct amount of caster and you should see a huge difference. Note, you will most likely need new center pin/bolt for the leaf pack on each side. easy to obtain and install.

 

So, shims are in, and as someone stated earlier, sloppy and jumpy are not the same things. Much less jumpy now, but still wanders in the lane. Now on to looking at steering