XJ Mods VSB 14

[rainman]

Originally Posted by alexbrown64

The other problem is the left pull. They are still working on this. A few offset ball joints are being used, but they are also working on some bump steer. They are saying it has a drop pitman arm that could be causing it.

Strange, as i have never done a pitman arm swap, but the world is a strange place...



Whoohooo..

drop pitman arms arms are for preventing bump steer, when you lift the mounting point of the track bar- IIRC Rhd ZJ have the same pitman arm as RHD XJ's.
to stop pulling to the left increase the wheel base on the left hand side of the vehical so that it is 5mm longer than the right side.
the right side is 10mm longer than left from factory.

last paragraph:
http://gojeep.willyshotrod.com/HowtoAlignment.htm

good luck with it.

[alexbrown64]

Got the Jeep back and to say i am disappointing is an understatement.

Diffs are great. A lot quieter and smoother now. So that is a plus.

Steering is up the shit. It pulls even worse to the left now. Before was just a very mild slight pull when you were on an off camber. Now, if you let go of the wheel, she will dart off the road.

This is what they did:

Replace LH upper ball joint with +0.5 offset
Replace RH upper ball joint with -1.5 offset.

How could this set up make the Jeep pull to the left severely??

They also played around with the offset on the upper arms and tried to tune out any vibes in the drive shaft by changing the pinion angle ( i have double adjustable control arms )

I have about a 5" lift.

They did say that after checking the pitman arm again, it is an original size one, but aftermarket.

I thought too that a lowered pitman arm would help with bump stop.

Anyway, i didn't think my bumpstop was a problem. Maybe i was used to it, but it never did anything unusual.

Not sure what to do now. I go back to work tomorrow for two weeks. I'm not taking it back there.... too much hassle. Took me a train and an Uber just to get it there, and same again to go and get it to bring home.

I am thinking of taking it all back to standard upper ball joints. Adjust the control arms so the left side is 10mm longer than the right, add a Return to Centre damper, perhaps add a ZJ pitman arm, adjust caster so the steering is a bit lighter again (and less pinion angle), and then see where i am.

Might have to put all my efforts and research into this new project..

Not sure what happened, but it sucks.

Cheers,

[awg]

there is no way any vehicle should pull to one side imo, so something must be wrong, damaged or bent

I do all my own caster, camber and toe measurements and adjustments, following an incident of stupidity from an alignment shop with one of my vehicles.

No Lasers need, just tape measure, a 4m long straight edge, and electronic angle finder (and make a simple jig for camber)

Yes it is a fair bit of work, but if the pros manage to completely fk things up, that leaves no alternative

You need a dead level surface, and someone to twist the steering wheel

Its hard to do, but every dimension must be taken, especially each side from dead centre.

I presume you have done the most basic thing and measured that when your steering wheel is facing dead ahead, the wheels are both facing dead ahead with zero toe in ? (in spec for an XJ)

I would fit a ZJ Pitman arm

[awg]

I have fruitlessly argued this case before, but in my not so humble opinion, and Adjustable Trackbar must be properly fitted to any lifted XJ.

I know for an absolute indisputable fact of both measuring (and simple laws of geometry) that following a lift, the entire front axle assembly is offset to one side.

That means the front wheels and rear wheels run in a different track

Shop Laser alignment "allows" for this..but does not correct the issue.
This is very misleading imo

the 4m long straight edge will show the problem.
Even can be measured with jack stands and string

People can tell me it doesnt matter till they are blue in the face, but I simply do not believe them

[LuluBelle]

I am not as tech as you guys but I understand what you are saying surely they didn't forget the wheel alignment all together?
_____ooooo
/__l_l_,\____\,___
l_---l_l__l---[ ]llllll[ ]
_.(o)_)__(o)_)--o-)_)

[oldon]

You probably already know this Alex but back near the end of last century I was snooping around at Caterpillar in Brisbane & found a brand new lazer truck wheel aligner waiting to be installed so I had to check it out. Read some of the instructions and the bit I remember was. (With the vehicle at normal ride height, all axles must be set parallel to one another, do not perform any other adjustments until this is done.) Roughly same time period I read an article by Bruce Reilly of Narellan truck align about aligning truck axles saying similar thing, also they set right side caster on the front axle at 0.5 to 1 degree less than the left side to counteract road camber. They bent & twisted axles to get their figures where they wanted them. Back then they were the go to place for truck steering problems. On the xj I'd check the rear axle measurement for square to the body first. the spring centre bolt is usually not a tight fit in the hole on top of the diff mount allowing a little wiggle room. then measure longditudinal & diagonal to front diff from rear diff & find a happy medium. Sorry for the long winded post Alex, got on the soap box there.

[awg]

Originally Posted by LuluBelle

I am not as tech as you guys but I understand what you are saying surely they didn't forget the wheel alignment all together?
_____ooooo
/__l_l_,\____\,___
l_---l_l__l---[ ]llllll[ ]
_.(o)_)__(o)_)--o-)_)

according to my inquiries, a shop Laser alignment machine will "correct" for offset axles, so the printout you get does not measure this condition at all

therefore what I do is first establish the rear wheels/tyres have zero toe in (which they should have on (probably) all vehicles, and can be done simply with a tape measure by measuring the rear insides (preferably) rim or tyre

These two measurements should be the same, or rear toe is out

Once that is established, if you do not have a 4m straight edge,
set up 4 jack stands, run taught string. It should just touch the front and rear of all 4 tyres

(A straight edge means you can use the rim, which is more accurate)

If the front axle is offset, or toe is incorrect, this will clearly and obviously not be the case

For example, a 2" lift will shift the front axle assembly ~ 1/2"

You can use an online trigonometry calculator to prove this out

I would expect a 5" lift to offset the axle about 1"

I would be surprised if such a well built truck has not has this matter attended, however, following my discussion with pro wheel alignment specialist, I was dumbfounded by their incompetence in respect of a Vintage vehicle I own and rebuilt the front end...even after I showed them what needed doing, they wanted to argue with me, insisting they knew best.

I had to get under the hoist and show them the steering wheel position was irrelevant, and would lead to an improper setting, they still managed to fk it up so bad the front tyres scrubbed in 100 miles...morons

On this vehicle, the setting was done by inserting a 1/4" diameter drill bit into cutouts in the steering box..once everything else is correct, the steering wheel is removed and placed on the splines in the dead ahead position as the final step..hope all that isnt too boring for youse all