caster on 00' low pinion

[whosyourdaddy?]

I checked out the go-jeep post regarding caster and toe-in and I'm looking for some help. I started by leveling the jeep via magnetic protractor on the transmission brace. Didn't know if that was the correct way but it was the only option I had.

Checked caster at the bolt heads on diff and measured 84.5*

Judging from go-jeep site,

90-84.5=5.5

original caster of 12-5.5=6.5*

now how can I have factory caster after lifting with 3"ome lift zj springs in the front new leaves in the back.

I have jks q' discos, rustys hd tracbar mount, rustys tracbar, new tre's on pitman, both ends and drag link.

Toe in is 1/8" with mad death wobble. Trac bar popped on me once and that's after replacing the mount end with bushing instead of tie rod.

Now for the stupid question, how do you tell a hp from lp d30?

I'm thinking with lift and 6.5*caster I have the hp which would really be
9*-5.5*=3.5*caster.

TIA

 

[whosyourdaddy?]

Looking at the pinion on the d30 looks as low as it could get in the pumpkin. Looking at yucca-mans axle tech says all xj 00's have hpd30? Is that a typo?

Signed,
Lost

 

[rpraterxj]

Looking at the pinion on the d30 looks as low as it could get in the pumpkin. Looking at yucca-mans axle tech says all xj 00's have hpd30? Is that a typo?

Signed,
Lost

My 2000 XJ definitely has a LOW pinion. I have been told that all pre-97 models have the HP and '98-'01 mostly will have the LP.

I am not expert, just my 2 cents.

RP

 

[whosyourdaddy?]

Pretty positive now that I researched a little that it is lp. Yuccamans tech kinda threw me off.

The whole reason for this is cuz I'm fighting dw. Shook the wheel so bad I thought I was gonna die going 55 with wife and kids.

Gonna try and change tires. Mine are cupped bad after installing the lift and not aligning it after. Finally got to the alignment but I think it's too late for the BFG A/T's.

Just trying to figure out if I need to shim the caster out now. Seems like it is perfect but I must be doing something wrong. Too low on cash to send it out and my 4 month old isn't ready to work on jeeps with me so I'm stuck between a rock and a shim.

 

[DaffyXJ]

Caster angle in and of itself does not cause death wobble. Caster impacts the abilty of the steering gear to return to center after a turn. If the steering wheel centers after a turn, caster is not so far out as to be a problem. Remember, pinion angle is more important than a perfect caster angle.
If you have finally gotten an alignment, what was the actual caster setting at the ball joints? That is where it is measured from. How much past verticle the knuckle is. On an XJ (LP) is it +7 deg preferred, a range of +5.25 to +8.5 degs and a max variance of 1.25 deg left to right. Where positive caster has the top ball joint angled to the rear of the vehicle. The alignment should have measured the caster for ya.

DW is caused by oscillations in the front suspension/steering. Short of saying look it up, start hunting for loose TRE's, sloppy track bar bushings, worn steering stabilizer, warn ball joints, loose/warn unit bearings, since you mention you have new TRE's everywhere, change the stabilizer.

Just a few comments.

 

[whosyourdaddy?]

stabilizer is in great shape. i'm thinking cupped tires is my deal. they are probably that bad. no one in town has degree shims. how do you check the play on the ball joints.

I'm looking for the measurements taken from the alignment. Gotta find my paperwork.

Looks like all my bushings are ok on my control arms as well. Need to take a pry bar to some things and see how they move I suppose.

 

[Ivan]

My 2000 XJ definitely has a LOW pinion. I have been told that all pre-97 models have the HP and '98-'01 mostly will have the LP.

I am not expert, just my 2 cents.

RP

It's actually the 2000's and up that went to the LP D30 due to a change in the exhaust manifold that needed more clearance over the HP D30.... AFAIK, the 98 & 99's are HP....

 

[Danno]

yeah, what Ivan said about the years. We have a '97 and a '00. your DW is usually caused by the track bar being loose as well as possibly bad tires. EVERYTIME I've had to deal with DW I always start with the TB and usually it's the end on the axle. It usually is either worn out and or the bolt has wallered out the mounting hole in the bracket. A lot of little things really mount up. Both our rides I put the JKS track bar replacement and the DW disappeared.

 

[whosyourdaddy?]

It's actually the 2000's and up that went to the LP D30 due to a change in the exhaust manifold that needed more clearance over the HP D30.... AFAIK, the 98 & 99's are HP....

I have to have the lp. Just got done rotating the tires and getting all the grease off the inside rims from overgreasing the old tre's.

Overgreased the damn tre's and the grease was all over the wheels. There was enough grease that came out of the old tre's that it probably had my wheels out of balance.

Going to also try to lower air pressure from 36 to around 32 if that makes sense to see if that will help the cupping. They are cupped but who knows how much cupping make dw.

Still haven't driven it since rotating and cleaning. I'll keep y'all posted and thanks again.

 

[RCP Phx]

That sounds like to much toe-in but you havent said what size tires your running.

 

[whosyourdaddy?]

Just drove around the block and dw is gone. Won't be the first time it has come and gone. Drives me crazy. Only thing I changed was air pressure and rotated tires. I don't have it in me to raise air pressure again to see if that was it or the rotation. On second thought I've spent so much time on this I'm gonna have to just to ease my mind.

Tires are 30x9.5x15's. Toe in is 1/16" on my last measurement. Doing all this with no help so I haven't perfected toe in measuring yet! So many posts on how to do it I should be a master in about a day!

Can someone loan me some cash to get some tires? :kissyou:

 

[Twisted Copper]

In my experience cupping has been caused by under inflation, lack of rotation, or both.