Caster and Pinion Angle Adjustment...
04-13-2012, 07:54 PM
#1
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Year: 1999
Model: Cherokee
Engine: 4.0
Caster and Pinion Angle Adjustment...
Just installed my RC 4.5" with Adjustable CA and CAD bracket.
As per instruction, i adjust the control arms to RC spec,
(These are the measurement with control arm drop bracket for 4.5" lift)
LCA 15.75"
UCA 15"
When installing the LCA (together with the factory alignment bracket), i had the LCA all the way back against the CAD as you can see in the pic below.
Upon completing my installation, i suspect the caster is off as my steering wheel does not return to center. I extended the LCA by a turn and now the steering wheel does return.
Here are some question i wish you can help...
Took it to a 4x4 shop for an alignment and have my 32" tires mounted at the same time.
1)Instead of mounting the tires, then do the alignment.....he align with my old semi-worn out 28", then aligned.
Does this sounds right?
2)Was told my caster was off and he did some LCA adjustment by pushing the CA forward. You can see from the below pic (not the actual pic but similar) that the LCA/CAD bolt is pushed forward compared to the previous pic.
Should the LCA be extended (since i have adj CA) rather than pushing it forward. His way would give the LCA a chance to move backward since its only held on my one bolt.
3)Driving out of the shop, i realized that the front tires are rubbing against my front bumper cap when the wheels are at full lock.
Did the mechanic adjust my axle too much forward? Should he had reduce the UCA instead of extending the LCA?
It drives fine for now, except it pulls a little to the right.
Also i have no from front drive at the moment so can't know if there is any vibration due to pinion angle.
Here is the report
Sorry for the loooong post.
Would really appreciate if i can get some help.
.
.
As per instruction, i adjust the control arms to RC spec,
(These are the measurement with control arm drop bracket for 4.5" lift)
LCA 15.75"
UCA 15"
When installing the LCA (together with the factory alignment bracket), i had the LCA all the way back against the CAD as you can see in the pic below.
Upon completing my installation, i suspect the caster is off as my steering wheel does not return to center. I extended the LCA by a turn and now the steering wheel does return.
Here are some question i wish you can help...
Took it to a 4x4 shop for an alignment and have my 32" tires mounted at the same time.
1)Instead of mounting the tires, then do the alignment.....he align with my old semi-worn out 28", then aligned.
Does this sounds right?
2)Was told my caster was off and he did some LCA adjustment by pushing the CA forward. You can see from the below pic (not the actual pic but similar) that the LCA/CAD bolt is pushed forward compared to the previous pic.
Should the LCA be extended (since i have adj CA) rather than pushing it forward. His way would give the LCA a chance to move backward since its only held on my one bolt.
3)Driving out of the shop, i realized that the front tires are rubbing against my front bumper cap when the wheels are at full lock.
Did the mechanic adjust my axle too much forward? Should he had reduce the UCA instead of extending the LCA?
It drives fine for now, except it pulls a little to the right.
Also i have no from front drive at the moment so can't know if there is any vibration due to pinion angle.
Here is the report
Sorry for the loooong post.
Would really appreciate if i can get some help.
.
.
04-13-2012, 08:01 PM
#2
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Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
arm should be to the back of slot deff then adjust arms by chart...http://www.lunghd.com/Tech_Articles/..._Arm_Chart.htm
04-13-2012, 08:07 PM
#3
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Year: 1999
Model: Cherokee
Engine: 4.0
Read this at http://www.yuccaman.com/jeep/dw.html
Does it make any difference adjustable CA or not?
Based on my limit experience (from reading), increasing caster would automaticlly lower the pinion angle relative to the TC?
The more i read, the more i'm confused.
Poor Alignment (Part II). Lifting the Jeep involves changing the caster of the axle. If the stock control arms are used, the pinion will start pointing down, away from the t-case output shaft. As it points down, it changes the caster of the axle and therefore throws off the self-centering engineered into the axle. Remedy this by using adjustable control arms.
These figures are according to '94 factory manual except where noted. (may vary for 2000+ low-pinion axles and pre-91 disconnect axles).
Camber (not adjustable) = 0 degrees (+1/2 to -3/4 acceptable)
Caster = Manual tranny +6.5 degrees, auto tranny +8 degrees (5 to 9 acceptable)
Toe-in. Depending on the year of your Cherokee, toe settings will vary.
87-94 you want 0" inches, + or - 1/16
on 95-96 you want 0" +1/8 or - 3/32
on 97-98 it's 0" +1/4 or -3/32
on 99-2001 its 1/8" +3/32 or - 1/8
These figures are according to '94 factory manual except where noted. (may vary for 2000+ low-pinion axles and pre-91 disconnect axles).
Camber (not adjustable) = 0 degrees (+1/2 to -3/4 acceptable)
Caster = Manual tranny +6.5 degrees, auto tranny +8 degrees (5 to 9 acceptable)
Toe-in. Depending on the year of your Cherokee, toe settings will vary.
87-94 you want 0" inches, + or - 1/16
on 95-96 you want 0" +1/8 or - 3/32
on 97-98 it's 0" +1/4 or -3/32
on 99-2001 its 1/8" +3/32 or - 1/8
Based on my limit experience (from reading), increasing caster would automaticlly lower the pinion angle relative to the TC?
The more i read, the more i'm confused.
04-13-2012, 08:09 PM
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Year: 1999
Model: Cherokee
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arm should be to the back of slot deff then adjust arms by chart...http://www.lunghd.com/Tech_Articles/..._Arm_Chart.htm
Thx freegdr.
That was my initial setup before the alignment shop adjust it.
If i push it back and go back to my old measurement....that caster would be off again.
Should i extend the LCA or reduce the UCA? I'm trying to move the axle back and at the same time increase the caster.....make sense?
Last edited by BotakBeng; 04-13-2012 at 08:11 PM.
04-14-2012, 01:12 PM
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Year: 1999
Model: Cherokee
Engine: 4.0
Hub to hub as in eye to eye?.....sorry if it sounded dumb (newbie here
)One more question....
What adjustment do i need to do to push the front axle back but retaining the caster angle? (my tires are rubbing the front bumper caps)
04-14-2012, 02:16 PM
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Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
101 is wheel base center to center-86.5 is 3.5 gegrees up from you pinion running parallel with the ground...http://go.jeep-xj.info/HowtoAlignment.htm
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04-14-2012, 06:32 PM
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Model: Cherokee
Not quite understanding you....are those numbers angle or length.
Hub to hub as in eye to eye?.....sorry if it sounded dumb (newbie here)
One more question....
What adjustment do i need to do to push the front axle back but retaining the caster angle? (my tires are rubbing the front bumper caps)
Hub to hub as in eye to eye?.....sorry if it sounded dumb (newbie here
)One more question....
What adjustment do i need to do to push the front axle back but retaining the caster angle? (my tires are rubbing the front bumper caps)
04-14-2012, 07:29 PM
#9
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Year: 1999
Model: Cherokee
Engine: 4.0
101 is wheel base center to center-86.5 is 3.5 gegrees up from you pinion running parallel with the ground...http://go.jeep-xj.info/HowtoAlignment.htm
Center of front and rear hubs(your wheels) find the center of each and have someone hold the dumb end of the tape on center of one wheel while you pull the tape to the center of the other,factory wheel base is 101.4. 86.5 is the reading you want when using an angle finder on you diff ( caster ) you can buy angle finders at home depot for about $10.00.once you have the LCA's adjusted so the WB is 101.4,then set your UCA's caster (86.5) .86/.87 is also acceptable..
I think i fully understand now.
I'll work on it tomorrow.......will update.
I really appreciate the time taken to help me out
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