Vibe-zilla after shimms (1 Viewer)

[waaz]

Hello
Not a expert in the steering field. But from what I have gavered, you need to have negative caster to track propperly. Think of a shopping cart, the wheels tilt back.
Every vehicle has neg caster, or 0 caster. Go to steering shop and get a reading
on their computerised steering rack, and go from there.
To much neg caster is no good either. The guys that do SOA, twist their axels to get neg caster to track while going down the road.
Just my $ worth.
waaz

 

[Greg_B]

Hi Waaz

Short compilation of threads on Mud that deals with caster

https://forum.ih8mud.com/showthread.php?t=30364

https://forum.ih8mud.com/showthread.php?t=18798

https://forum.ih8mud.com/showthread.php?t=8630

There are a couple of pages of links to threads if you do a search of all forums with the words "positive caster" in them.

I ain't no steering expert either, however the general trend is 1deg+ caster is stock, and go up to 4deg+ when running large tires.

hth's

gb

 

[waaz]

Hello Gregg_B
I had a bad steering issue wit my BJ42, It wandered very baddly, wanted to change lanes with out asking ect.
Took it to Kal Tire and had it checked out. I was + 2.5 on right side and + 2 on left side. (caster)
I put 4 deg shims under springs to bring me back to neg caster. Like day and night difference.
Tracks good now. Can drive with one arm.
Bj42 has no power steering. Could be vehicles with no PS need more neg caster
waaz

 

[waaz]

Oh yes should also say that I have big shackles and 32 x 10;50 tires, add a leaf
waaz
PS soorry to hi jack

 

[Greg_B]

Hello Gregg_B
I had a bad steering issue wit my BJ42, It wandered very baddly, wanted to change lanes with out asking ect.
Took it to Kal Tire and had it checked out. I was + 2.5 on right side and + 2 on left side. (caster)
I put 4 deg shims under springs to bring me back to neg caster. Like day and night difference.
Tracks good now. Can drive with one arm.
Bj42 has no power steering. Could be vehicles with no PS need more neg caster
waaz

Is the thick side of the shim facing the front or the rear?

gb

 

[waaz]

Thick side to rear, pushing pinion up
waaz

 

[beanz2]

Hmmm, this doesn't make sense. Placing the shim in that manner does indeed make the caster more negative, but theoretically that would make the wheels follow the ruts more. Not that using shims in the front is a good idea to begin with...

Well, whatever works I suppose

Dave

 

[Red Herring]

You have yours to the rear? I put my thick to the front. The new tie rods tighten everything up really nicely, but i have not had a chance to test her out... and won't really untill i get my new tires on tomorrow. I think i have a rim out of ballance, and it was noticable but managable without the shims, and just plain nasty post shimming. I will then take the rig into a local spring shop on Thursday to have it alligned, and figure out what the castor angle is. I am wondering if I have not over compensated with the 4 degree shim, and might noe be running 0 or -1 degree? We will see tomorrow and Thursday... either way I will fill you all in.

Man... talk about a sence of accomplishnemt! I loved doing the knuckle rebuild! Messy as all get out, but fun, and easy! I love these rigs! My only trouble was getting the splines to line up on the long drive shaft... easily solved once i figured out what was wrong, and the steering stabilizer is a real bitch to get off! Now the bolt spins in its seat, and i cannot get it back on properly...LOL! That can wait for the new suspension. Besides, i am of the camp that you should not need a steering damper to help with steering issues. The beast should drive well without it, and even better with it. So new bearings all round, 4 new tie rod ends... new tires, and alignment. If it still wobbles after all this, Im gonna start really scratching my head! I will see what the shop says, but i think i will get the alignment done with the axle unshimmed... and go from there.

Thanks for all your help everyone!

 

[Greg_B]

You have yours to the rear? I put my thick to the front. I am wondering if I have not over compensated with the 4 degree shim, and might noe be running 0 or -1 degree? We will see tomorrow and Thursday... either way I will fill you all in.

If you put the thick to the front you increased caster, and are likely +. You may still be negative, but that means you would have been over 4 deg- to start with.

Good on you for the knuckle build.

I've yet to get the steering box on mine, or increase caster 1deg+ more.

gb

 

[crushers]

i have found that the more positive the caster the better (up to a point of course) 6 degrees shims work great in making those fat meats stay in their won lane.
caution:
you do get electrolisis with the aluminum shims so check the shims once a year for wear AND get a longer centering pin head to keep it all together. you need at least 1/2" of head stick above the shim...
i had one of my own trucks with the axle shifted backwards due completely to the centering pin not having enough meat above the shim...
cheers

 

[Red Herring]

Im an idiot... i admit it freely, an idiot!!!!!!!!

Sooooooo group..... whats the most likely mistake a nooby dim WIT (wrench in training) might make when shimming an axle???? Hmmm??? I think you all know??? YES... Not making sure the spring pins were long enough!!!! Im an idiot! So... death wobble... yup due to a bad alignment. Axle had stepped backwards 1/2 inch on the left side. Pulled the wedges this AM... noticed my gaffah... and low and behold - - -> NO SHIMMY!

PS... Had the new tires put on today. FANTASTIC. Best $$ spent so far. They are 32X11.5X15 Pro Comps, and I am loving them. The A/T certainly suites me better, and they are really quiet.

 

[Greg_B]

Spector lists stock as -1 deg. I gather from this dialogue that extended shackles increase caster towards the positive, but also that larger tires work better with more postive caster. I'm interested in this because my 62 has Spector 2" shackles in front without shims and I'm wondering whether or not to shim. (running 31's) No problems with steering for the two years I've had it.

Dunno 89GASHOG. The 1984 HD Chassis Manual 36262E calls for either 0.50 deg positive caster, or 1.05 deg positive caster, + or - 1 deg for both, depending on if it's a G or V version FJ62, BJ-HJ60L(R) respectively.

The older publication 36044E called for positive 1 deg FJ/BJ/HJ4* series, + or - .45 deg, and 1.05 deg positive caster for the FJ/BJ/HJ6* series + or - .45 Deg.

hth's

gb

 

[Greg_B]

Pulled the wedges this AM... noticed my gaffah... and low and behold - - -> NO SHIMMY!

Good for you! Hope my fix is that easy! Daily driving mine and it has not happened again, however I need to investigate and figure it out.

gb