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JK steering and alignment gurus help!?

NDCjeepsmith

NDCjeepsmith

Red Skull Member
Joined
Dec 8, 2021
Member Number
4600
Messages
546
Loc
SW Mo
2010 JKR on unknown lift. Probably a rough country, 5.6-6"

Had bent axles, took it to my trailer guy and he straightened the rear and put offset BJs in front.

The axles are centered, and measure square. Toe reads a **** hair under 1/8.

Castor on a printout reads 4.8 but my digital angle finder reads 5.5-6.5 depending on where I put it.

It still drives like shit above 35mph

When you go to correct to bring back to center it wants to over correct and I end up having to steer back and forth constantly.

I put all my lasers and measures on it today and what I'm seeing is odd shit on the driver's front. And even tho the axles are centered when shooting a laser from toe plates to rear tires they show on two completely different sides of the tires...???

When measuring from toe plates to centerline I get the same on the rear side of axle but on front the drivers is 1/2" short, that makes no sense.

Drivers also shows stub shaft not centered with Lazer vertical through hub???

But two different alignment shops said its in spec.

Has all new bushings front and rear.
New trackbars front and rear
New steering front
Used but good and different from before steering box
New BJs
New hubs

I'll post up pics of all the different crap I measured and try to keep each one on its own reply
 
Castor craziness and where I'm measuring.

Sheet says 4.8
I get 5.5 on knuckle flat pass side
6.5 on BJ

Drvrs I get 5.4 on flat and 4.6 on BJ

Pass side
20230922_130540.jpg


20230922_130614.jpg


Drvrs side

20230922_130712.jpg
 
Your axle is bent.

No mention of condition of tie-rods and panhard bushings.
 
Hub center weirdness

I set tie plates level and Lazer centered, inboard side of Lazer lined up with dot Lazer in center of tube

I then rotated toe plates to see how lugs lined up vertically top to bottom.

Pass toe plate level

20230922_122654.jpg


Pass lugs lined up

20230922_122721.jpg


Drvrs plate level

20230922_122434.jpg


Drvrs lugs lined up

20230922_122414.jpg


Notice on drvrs how the stub isn't centered???
 
How toe plates cast to rear.
Toe plates on back side measure the same to centerline.

Pass

20230922_134016.jpg


Drvrs

20230922_133948.jpg


How rear tires show compared to rear edge of bumper. I know it's not an end all point of measurement but it's close. Also the axle measures centered compared to centerline.

Pass

20230922_123429.jpg


Drvrs

20230922_123538.jpg
 
Help me wrap my head around it.

I'd like to know where it's bent and what not. There's very little room on the drvs side to stick a straight edge on the tube but where I have I doesn't show anything.

I also don't understand how or why it would measure out centered and square but throw the lazers so far off at the rear, or how the toe plates measure the same to centerline on back side but a half inch short on only drivers side on front side?

Just doesn't make sense. Nor does how would the stub shaft be not centered. Hubs weren't any more of a bitch to get out than normal.

Is it in the C or is the Knuckle somehow twisted???
 
New ball joints usually need to be worn in a little. I know my Jeep drove like crap for a couple of hundred miles afterward.
 
Before and after, no real difference. Before was unknown alignment but you could see by eye the draglink was bent and both fronts were toed out.

Axles were both not centered hence the new adjustable track bars.

I'm going to get the tires straight and see what it does. Even with a bent axle if I adjus hem to where all 4 are straight shouldn't it "OK"?
 
Get a 4 wheel alignment check. I fought a crazy tow issue with my FJ60 a few years back that never seemed to be fixed and it turned out my left rear was towed out by 0.1°. It’s not something that could be measured with camber / caster gauges. I would put my money that the rear is where you’re getting the strange behavior.

As an aside measuring the caster at the knuckle is always going to be incorrect. You have to measure at the WMS because the KPI angle is a component of it when you turn the wheels. Aka you need a camber / caster gauge or a laser alignment machine.
 
gt1guy said:
How did they bend the axle?

The C could very well be bent too. I see it's not gusseted.
Click to expand...
Bend the first time or bend to fix?

FordFascist said:
Get a 4 wheel alignment check. I fought a crazy tow issue with my FJ60 a few years back that never seemed to be fixed and it turned out my left rear was towed out by 0.1°. It’s not something that could be measured with camber / caster gauges. I would put my money that the rear is where you’re getting the strange behavior.

As an aside measuring the caster at the knuckle is always going to be incorrect. You have to measure at the WMS because the KPI angle is a component of it when you turn the wheels. Aka you need a camber / caster gauge or a laser alignment machine.
Click to expand...
It has been to 2 different alignments.

The rear was toed and cambered. Hence the second shop which has straightened trailer axles for me before.

The front was cambered hence offset balljoints
 
Yeah I was hate how wide it is. Won't fit between fenders on my car hauler unless I squeeze it in and don't care about the fenders being bowed out.

The rear is straightened now.
 
I imagine the offset ball joints are causing some of your reading error in the front. I’m not sure how square the pin is to the top. I.e., is the top of balljoint perpendicular to the axis of knuckle rotation?
 
I've always wondered which spot is best and usually land on hoping the BJ itself or a socket over it is best.

The bottom side of knuckle has some flats too and I put a straight edge across them and got the same as when it was on the upper flat portions
 
Those flats are definitely not perpendicular to the steering axis, if you have offset ball joints. Depending on how the ball joints are installed (which way they are offset) the angle between flats and steering axis can vary more or less.
 
I didn't install them nor have I ever messed with offsets... but I assume the line is the marking for where the change will take place. They're 1° and the line is on outer side of knuckle parallel with tube centerline.

Tires were cambered in at top so I'm assuming they brought it out a straight 1° to get 0 camber and that it would have very minimal impact on the castor
 
NDCjeepsmith said:
What?

I've never seen or heard mention of that much toe.
Click to expand...

When the tires are loaded your 1/8th turns to near zero.


Put the pinion flange at 0° That is going to be 4ish degrees caster. Compare to the reading on the Cs. A degree or two down on the pinion should put you where you need to be.
 
gt1guy said:
Bent the first time. What were they doing when they originally bent the axle?
Click to expand...
He's horrible about maintenance so no telling really. He finally just got tired of it driving like shit.

It was being wheeled decently hard and not being taken care of with no thought to strengthening up things either. He ran the Rubicon last year with a stop in Moab, but I'm petty sure it was like this for awhile.
 
A 1/4" of tow will melt tires.

I would recommend finding a shop with a modern rack which shouldn't be too hard. Have them rack the truck, do a caster sweep. Get the SAI and AI.

That will give you every number you need down to decimals. You'll not only know what angle is off but if it has a bent knuckle or C.

Once you have that print out you can use your laser to make corrections assuming it's an adjustment and not something bent.

I've also had junk steering boxes and tires do the same thing. Wouldn't hurt to check the box freeplay and find someone you can borrow a set of wheels from to rule them out.

The fact that your wheels have a large offset is also probably making whatever is going on much worse potentially.
 
Skinny said:
A 1/4" of tow will melt tires.

I would recommend finding a shop with a modern rack which shouldn't be too hard. Have them rack the truck, do a caster sweep. Get the SAI and AI.

That will give you every number you need down to decimals. You'll not only know what angle is off but if it has a bent knuckle or C.

Once you have that print out you can use your laser to make corrections assuming it's an adjustment and not something bent.

I've also had junk steering boxes and tires do the same thing. Wouldn't hurt to check the box freeplay and find someone you can borrow a set of wheels from to rule them out.

The fact that your wheels have a large offset is also probably making whatever is going on much worse potentially.
Click to expand...
Thanks for that info. I'll call around and see who can do specifically a castor sweep.

Whats "SAI" and "AI"?... steering angle inclination???

I'm also taking tires in to be balanced and gonna try to run it without spacers but I think they're on there cause he always buys a buddies used stuff and most of them are TJs so they're adapters for 4.5s.

But yeah I agree with trying other wheels and tires.

Never heard of a castor sweep so definitely thanks for that
 
Yes. Sorry I meant IA: Included Angle

SAI and the Included Angle Explained Illustrated

SAI and Included angle must be a procedure performened to check the frame parts and caster angle as it relates to SAI. What is SAI and the included angle?
www.freeasestudyguides.com

Putting your truck on the rack and doing all the measurements is going to tell you if you actually have something not only misadjusted but bent. You can certainly get camber and caster in spec but that doesn't mean you have perfect C's or knuckles.

In other words both left and right can have perfect camber but that doesn't mean one side isn't bent and adjusted using the balljoint to get it back to spec. So yes it matches but means you have an underlying problem.

I think normally all of this is unnecessary but if you've bent something and straightened out the alignment rack will tell you everything.
 
Agree with all the put it on a rack stuff but I also disagree... the thing still drives like shit, after 3 alignments and the last was a shop with the capability of straightening them.

Plus I've had a high-end shop I wanted to start doing more business with that totally fucked up a run of mill 3.5" metalcloak on a gladiator... I could literally see by the shit wasn't square, even, or straight... took them 5 fucking hours and they tried to charge me by the hr!

So my belief of "the rack is right" is hard to fall on.

I'm still going to fuck around with it and find tho but this week has been taken up by U4 in Disney.
 
Just because they have a rack didn't mean they gave you a tow and blow. The rack is only as good as the tech using it.

A basic alignment most guys will not lock the wheels and do a caster sweep. It's an extra step not required for an alignment.

Did they give you a printout of anything?

If the tech actually puts it in the rack, does a full sweep, and gives you a printout you will have every piece of information needed to make a call on what's going on.

This doesn't have to be a 4x4 shop either. Any tech that has a brain with a rack built in the last twenty years will give you all this info.

I'm not sure how you think setting up lasers and trying to measure all this on your own is going to give you better insight that an alignment rack literally designed to do exactly what you are doing down to the decimal points. Then spit a piece of paper out telling you where everything is 🤷
 
I don't expect to do the same or get th info a rack would. I'm sure you're 100% spot on with the "most times they don't do a sweep" that's why I'm hesitant to take a solid axle vehicle to a shop for an alignment cause usually they just center the steering wheel.

I got a print out from the first shop, not second but things have messed with since then too.


I actually got it driving better bit it's still not great.
 
First of all, never let a shop tell you "it's in spec". Most of these guys couldn't find their own dicks in the dark. Many have no clue as to what make a vehicle drive funny. They go only on the stock published specs, which for some vehicles are pretty wide in ranging. On a JK the wheelbases vary from 95.6" to 116" and the spec for the alignment are the same between the two. A shop may not know that a 2 door JK benefits from the higher caster number more than a 4 door as an example.

You can run slightly less caster with positive scrub radius on a solid axle vehicle as the SR also acts as a force to hold the wheels straight.

Second, can you get this thing on a rack with a laser aligner, get a printout and post it up? I'm going to again post the obvious that all those at-home tools are next to useless for anything other than measuring toe.

Here is the printout of my Land Cruiser that every shop couldn't figure out why it pulled left. Notice the left rear. You need to make sure they are measuring the rear axle.

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