[Spokerider]

Have a few Samurai steering related questions please guys.

What is the optimum caster angle for an SJ13 with power steering, 30" [measured] tires, yj spua?

Factory Suzuki caster angle is 3.5 degrees, plus or minus one degree. Factory front pinion angle is 10 degrees.
My front pinion angle is currently 10 degrees, which puts the caster angle right at 3.5 degrees positive.

My steering is "slow to return to center" after making a turn, and steering input is needed to get it to steer straight ahead again, once the turn has been made. It gets tiresome having to always make minor corrections to the steering wheel to get it back to tracking straight again. It should be tracking straight ahead, hands off wheel, by itself.

My steering box sector shaft adjustment is no too tight. I checked this already. No excess slop, and not too tight.
Toe "in" is set to 1/8" at the tread perimeter......on these 30" tires. More toe in needed?
Tire pressure is 28 lbs in the front...….prolly more than this vehicle needs for a full width foot print, but not wanting a lower tire pressure to be a factor in limiting steering return.

I had rebuilt the knuckles with all new seals and king pin bearings. King pin / knuckle turning torque was within factory spec [ before installing the knuckle wiper seals ]. I checked this when rebuilding the knuckles.

Should I install 2 degree leaf spring shims to bring the caster angle to 5.5 degrees, positive? Will this help return steering to center? Enough to make a difference?

Have any of you noted increased knuckle friction after rebuilding the knuckles and installing new rubber or neoprene wipers? Enough increased friction to impair the steering to be able to return to center, with hands off the steering wheel, after making a turn?
It may be matter of letting these new wipers "loosen" up some, with use.

Thanks.

[Gwagensteve]

what steering box? Is it still the 80 series one?
Is the car back to SPUA?
What steering arm/drag link/tie rod are you using?
How parallel are the drag link and tie rod at straight ahead?
I’d aim for 6 degrees

Don’t add more toe in. It will mess with the handling be make the car feel like it has loads of bump steer.

[Gwagensteve]

Oh, current rim backspacing?

Steering damper fitted?

[Gwagensteve]

Oh, total turns lock to lock?

[Gwagensteve]

and...

[Spokerider]

Gwagensteve wrote:

what steering box? Is it still the 80 series one?
Is the car back to SPUA?
What steering arm/drag link/tie rod are you using?
How parallel are the drag link and tie rod at straight ahead?
I’d aim for 6 degrees

Don’t add more toe in. It will mess with the handling be make the car feel like it has loads of bump steer.

Sorry for the late reply.....just busy with life stuff.

I've completed the spua conversion. Turned out pretty well. I am using the same FJ 80 box and made new tie rod and drag link. I used a combo FJ 60 tie rod end, the one with the hole for the drag link taper, and fj 80 TRE, and EMF brand chev 1 ton DRE's. The tie rod / draglink design I chose to build is the same Y design as the oem Suzuki design.

The tie rod / DL angles are good.....only about 10 or 12 deg difference between them at static suspension rest. I did need to move the front axle forward and inch to get the needed clearance between the tie rod and DL during suspension articulation.

I went with OME yj springs in the rear and modded my front yj's to match the ride height of the rear OME's. Bilstien shocks front and rear.

Yep...had to shorten both driveshafts too, and have modded the vw diesel oil pan for spua clearance.

After completing the spua conversion, the front pinion flange angle measured at 10 deg, which put the caster angle at 3.5 deg. I decided to re-install the 2 deg spring shims I had in earlier, when I was messing with the caster in spoa configuration. Now, the caster angle is 5.5 deg.

Others that have installed the Trail Gear rubber knuckle wipers after a knuckle rebuild have also experienced steering that was "slow to return". This may be the case with mine too. Seems the new rubber wipers have way more friction to them than the oem zuk felt wipers did. I'll try loosening the bolts holding the half-moon metal knuckle rings in place.....see if that reduces the friction enough to quicken the steering-return some. Anyone here experience this knuckle wiper seal friction?

I'm going to try some different wheels and tires. Will be removing the 15 x 8 2.5" back set wheels and trying Grand Vitara alloy 16" wheels. These are 7" width. I wanted 6" or 6.5" width, but cannot find any, so 7" it is..... Hoping the 4" back set on these wheels will work for me. I have 215 85 16 tires. I need the tire height [ diesel gearing ] but not the width of a 245 70 series tire...… Yes, they are E rated tires with stiff sidewalls. I'll see how low on the psi I can go with them.

I have not yet gone for a drive to feel the difference with the caster adjusted to 5.5 degrees, or with the knuckle bolts loosed to 6 lbs torque.
Guess I'll find out......

[Gwagensteve]

sorry, same same - busy.


Take the knuckle seals off and see how the return to centre is. If it's fixed, go back to felt.

The factory used urethane and felt (not rubber) for a reason, I'm guessing.