ok so i got my kit installed and sent to 4wheel parts for an alignment so here is what came back. shop foreman said that the jeep is still un road worthy and said that it has "memory steer" due to just changing out ball joints. he wasnt able to safely drive above 40mph. i asked if there was anything he noticed that needed fixed and they said no not even suggesting. im at a loss right now. any help would be great.
98 TJ bump steer diagnosis
- Thread starter AZ2CO98tj
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- bump steer pitman arm tj wrangler
posted alignment results. hope you or someone can clue me into the issue. thnks
Your total .30 toe-in is dead-nuts on, perfect. Your 3.4 degree caster angle is just over half of what it should be. Insufficient caster angle will result in poor steering return-to-center after completing a turn and unstable twitchy steering on a level highway. I'd want nothing less than 5.5 to 6 degrees. What size tires? I am concerned that both sides have the same 3.4 degree caster angle. The factory welded the knuckles into place to give .4 or so less of a caster angle on the driver's side than is on the passenger side. The L-R side caster angles should not normally be identical as your printout says they are. Makes me wonder how the shop measured them or if they actually measured both sides.
And you did get rid of that driver's side dropped front track bar mounting bracket, right? Ya gotta get rid of that, it's causing bump steer.
And you did get rid of that driver's side dropped front track bar mounting bracket, right? Ya gotta get rid of that, it's causing bump steer.
The area of interest is way off to the side, mostly out of view, and in a dark shadow. DId you intend for us to be able to see the driver's side track bar mounting bracket we needed to see that is not in the photo at all?
no it was the only picture i had at the moment. i realize it doesnt not show the trac bar and drag in relation to each other on the driver side. will get another picture up soon as i get it back. should i call 4wheel parts and have them adjust the caster to the specs your suggesting? thanks!!!!
ohiopatriot
TJ Enthusiast
Agreed.
Just FYI. The alignment equipment makes you go through a "caster sweep" which is turning the wheels about 25 degrees right then 25 left then steer straight ahead, the sensors/computer then calculate the caster of both wheels at once. You can skip that step and have no reading on the print out if you chose, but if you have a reading it's legit.
Oddly enough it's the only measurement a lazy tech can't cheat on the machine. Camber and toe can be manipulated without adjustments
. (Not that that happens )4wheel parts said that the jeep is not road worthy as i need to wait 100 miles to break in the new ball joints as this was the cause of my poor return to center???? even after the alignment. im at a loss right now with this thing. what am i supposed to do for 100 miles? drive in an empty field!?!
How do you explain the L-R side caster angles being the same when they should be .4 to .5 degrees apart? The TJ's knuckles are welded onto the axle tubes rotated .4 to .5 degrees apart from each other to create that L-R caster angle differential.
Ahem, cough cough, um booollllshit. Ball joints don't need to be "broken in".
ohiopatriot
TJ Enthusiast
Things get tweaked/bent over the years. If they didn't you would never need an alignment until you changed things.
Most unibody vehicles only come with provisions for toe adjustment. Over the course of time we add cam bolts, slot holes etc to compensate for what the manufacturer didn't provide.
Are you serious? The knuckles set the caster angle differential between the sides and they are welded to the axle tubes which don't twist to remove the required caster angle differential unless from a serious impact or similar. The caster angle relationship between the left & right sides stays a constant unless there was a major impact with the axle that twisted one side.
Not to mention it would take a very precise amount of axle tube twist to make the two caster angles exactly the same as the printout indicates.
ohiopatriot
TJ Enthusiast
I think some TJs have cam bolts in the lower control arms for caster. Maybe your thinking camber isn't adjustable. But it is with aftermarket balljoints.
We're not talking about camber angles here which are not adjustable without adjustable aftermarket ball joints.
Yes '97 to mid-99 TJ have cam bolts for the caster angle (+/- 1.5 degrees) but the L-R caster angles are not separately adjustable. The two side caster angles are locked together since the knuckles are, again, welded to give the different L-R caster angles that are required and part of the normal axle setup.
ohiopatriot
TJ Enthusiast
Look Jerry, I just stated how the equipment works. Your the undisputed Jeep God so you tell me how the caster is the same. The measurement can't be manipulated, so it is what it is.
That's why I questioned the same-same measurement shown on the printout. Something isn't right somewhere.
ohiopatriot
TJ Enthusiast
So, we have it's not adjustable, but its the same, how can that be?
Let's list possibilities, I'll start....
1) something bent
Let's list possibilities, I'll start....
1) something bent
Right, you betcha. Something bent precisely enough to move the L-R caster angles from their correct .4-.5 angle difference so they are now exactly (but incorrectly) the same... as they're not supposed to be. Right.
ohiopatriot
TJ Enthusiast
Ok, soooo....what's your answer? You attack me with your condescending attitude, but have no plausible answer? For the betterment of the Jeep community something should be done.
As I said, I just stated how the machine works, they look to you for all the answers.
2) adjustable balljoint?