Question about Front Pinion Angle - JeepForum.com
 
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post #1 of 8 Old 01-02-2014, 11:02 AM Thread Starter
NoNative
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Question about Front Pinion Angle

I moved up from an 2.5" YJ springs to the RE 4.5" HD YJ springs earlier this year. Huge fan of the new springs, but I'm a little concerned about my front pinion angle.

To get the caster in spec (around 6 degrees positive) I installed steel degree shims in the spring packs. The end result, as you'll hopefully be able to see from the two pictures, is that the pinion angle is not remotely lined up with the drive shaft. I've got the rear lined up correctly, but I'm afraid that the front pinion angle will put a ton of strain on the u joint between the drive shaft and front pumpkin.

I've researched where I can cut then re-weld the "c's". I see where others have shaved a few degrees off the spring perch, but I don't think that would be enough alone to get the pinion angle lined up.

Bottom line, is this something I need to be concerned with? If not, what's the consensus on the best way to change it? I'd like to avoid having this break on the trail.

Thanks in advance for your help!

Taylor

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1986 CJ-7 Laredo, 258, AX15, AC Dana 30/44, Ox Lockers, Howell TBI, DUI, 4.5" RE YJ Springs, 1.25" BL, clocked & twin-sticked Dana 300 with Lomax 4-1, 4.10s, 33s, PB, 8000# winch, YJ Roll Bar, Factory 20 gallon tank.

1984 CJ-7 Renegade, 258, T4, AC, Howell TBI, DUI, 2.5" OME YJ Springs, 3.53, 31s, PB, Warn bumpers & 8000# winch, Factory 20 gallon tank

1984 CJ-7 Renegade, 258, Auto, AC, 3.31s, PB, Factory 20 gallon tank, Bone stock except for 31s
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post #2 of 8 Old 01-02-2014, 11:45 AM
CSP
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That angle isn't bad at all. It certainly isn't going to bind. Stock CJ rear shafts have more operating angle on them than your front pinion has.

Shaving a few degrees out the spring perch would be counter productive to the fact that you added shims to make everything move the other direction.
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post #3 of 8 Old 01-02-2014, 11:56 AM
locohosa
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(Please correct me if I am wrong)

With the hubs locked out, and the T-Case in 2wd, the front u-joints should see hardly any activity compared to the rear. My understanding is that the front can have tighter angles because the ujoints see less strain...

I have been wrong once though.

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post #4 of 8 Old 01-02-2014, 12:06 PM
TIPPEDITOVER
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The only time you rotate the pinion up to match the driveline angle is when you are running a double cardan (CV) joint at the t-case. If you are just running standard single u-joints on both ends then parallel your axle pinion angle to the t-case pinion angle.

Remember as the axle moves downward, the u-joint will see more of an angle. Let the front axle hang, rotate the u-joint and see if it's binding. If not then wouldn't worry.

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post #5 of 8 Old 01-02-2014, 12:27 PM Thread Starter
NoNative
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Quote:
Originally Posted by TIPPEDITOVER View Post
The only time you rotate the pinion up to match the driveline angle is when you are running a double cardan (CV) joint at the t-case. If you are just running standard single u-joints on both ends then parallel your axle pinion angle to the t-case pinion angle.

Remember as the axle moves downward, the u-joint will see more of an angle. Let the front axle hang, rotate the u-joint and see if it's binding. If not then wouldn't worry.
I forgot to mention that I am running double cardan (CV) drive shafts shafts in both the front and rear.

1986 CJ-7 Laredo, 258, AX15, AC Dana 30/44, Ox Lockers, Howell TBI, DUI, 4.5" RE YJ Springs, 1.25" BL, clocked & twin-sticked Dana 300 with Lomax 4-1, 4.10s, 33s, PB, 8000# winch, YJ Roll Bar, Factory 20 gallon tank.

1984 CJ-7 Renegade, 258, T4, AC, Howell TBI, DUI, 2.5" OME YJ Springs, 3.53, 31s, PB, Warn bumpers & 8000# winch, Factory 20 gallon tank

1984 CJ-7 Renegade, 258, Auto, AC, 3.31s, PB, Factory 20 gallon tank, Bone stock except for 31s
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post #6 of 8 Old 01-02-2014, 12:55 PM
CSP
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I still wouldn't worry about it. It's not going to bind. You may have some vibration if the hubs or locked or the tcase has the front axle engaged at highway speeds.

If you really want it to have zero pinion angle the only option is to cut the inner knuckles and rotate them. Any other method is going to alter caster, which takes priority over pinion angle.
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post #7 of 8 Old 01-02-2014, 01:05 PM
Spieg8
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Quote:
Originally Posted by NoNative View Post
I forgot to mention that I am running double cardan (CV) drive shafts shafts in both the front and rear.
Why CV in the front? Seems like a lot of unnecessary trouble. As mentioned before, the length of the front driveshaft allows for more lift before safe working angle is exceeded. Never seen a need for CV shaft in front with less than 6" lift.

In order to satisfy the angles required for caster and for pinion with CV joint, you will most likely need to rotate the inner "Cs". Personall I'd replace the driveshaft with standard u-joints.
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post #8 of 8 Old 01-02-2014, 01:10 PM Thread Starter
NoNative
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Thanks for the guidance. I'm going to roll with it as is. I'll keep a spare U joint in the Jeep in case it craps out on the trail.

1986 CJ-7 Laredo, 258, AX15, AC Dana 30/44, Ox Lockers, Howell TBI, DUI, 4.5" RE YJ Springs, 1.25" BL, clocked & twin-sticked Dana 300 with Lomax 4-1, 4.10s, 33s, PB, 8000# winch, YJ Roll Bar, Factory 20 gallon tank.

1984 CJ-7 Renegade, 258, T4, AC, Howell TBI, DUI, 2.5" OME YJ Springs, 3.53, 31s, PB, Warn bumpers & 8000# winch, Factory 20 gallon tank

1984 CJ-7 Renegade, 258, Auto, AC, 3.31s, PB, Factory 20 gallon tank, Bone stock except for 31s
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