Front Pinion Angle

[exjay82]

I've read through all the post on here and can't find a solid answer, all I find is arguing. If i'm trying to set my front pinion angle.

1. Can I take my reading off the top of the upper ball joints?

2. Does the axle need to be rotated so that the chunk is pointing up towards the tcase or down towards the ground.

 

[WB9YZU]

No, you use a socket and an angle finder on the u-joint caps. See FSM for drawings. DS/ Pinion angle is relative to the DS and NOT the ground.

When lifted, you have to make lemon-aid. The FSM calls for a zero degree difference, + /- a Degree between the pinion angle and the drive shaft angle.

When you lift and XJ, it rotates the axle a bit, which upsets your caster angle, and your DS angle. You have to decide which is worse, a poor handling vehicle (Caster), or a bad pinion angle . Most people opt for a compromise which gives them an acceptable Caster angle and only a slightly poor DS/Pinion angle.

 

[exjay82]

yeah that didn't help at all, it just confuses me more.

does the chunk need to point more downward or upward to get the 5-9ish degrees everyone is always talking about?

But you did confirm that I can measure off of the top balljoint, so thanks for that.

 

[Sero]

The ball joint has nothing to do wiith pinion angle. Zuki was describing how to measure the pinion angle and makes no mention of measureing off the top of the ball joint.

 

[thechief86]

i think ol' dude was more interested for alignment and steering reasons than for driveshaft angles. i could be wrong, though. for that, you want ~4-7* positive caster, which will point the pinion toward the ground ever so slightly. this will help with deathwobble issues, but put the ujoints at a higher risk of binding.

 

[exjay82]

thanks chief...and am i correct that I can measure off the top of the upper ball joint to get those measurements?

 

[oblivion_twister]

if you're on level ground, otherwise you need to measure the angle of the pad you're on and the subtract or add it to the reading but reading directly on the upper ball joint isn't a true measurement.

 

[nismo5]

what in the world is the chunk ?? so i can understand the sollution to the problem

 

[1990heepxj]

im going to assume what hes calling the chunk is the differential

 

[thechief86]

chunk= diff housing fer us suthern redneck simpletons.

 

[Builderxyz]

This covers it all...buy yourself a angle finder $10.00 at home depot..Alignment he gives diff angles for variuos lift heights also..none of this infromation will do you any good if you don't have your lowers adjusted according to your lift height.Yucca-Man: Rubicon Express RE9900 Drop Brackets

 

[philagony94xj]

If you are trying to set your Caster, then yes you can use the upper ball joints to set the axle at an angle to get your "5-9degree" numbers you so desperately want.

As for your ORIGINAL question of setting the "pinion angle". When people say they want to set that angle usually they are refering to the relation of the D.S. angle coming down from the transfer-case and the angle of the front axle where the D.S. meets. I.e. Zuk's answer for measuring the front axle pinion angle and getting it matched up with the front D.S. angle.

If you are gonna ask a question about setting something in the front end please be clear as to what you want to set, because I read your original question the same way Zuki-Ron did as well. You are using two different terms that have a slight relation to eachother, but neither is used together when setting angles. I.e. Upperball joints and pinion angle.

We want to help you out, but you have to help us out by being a little more clear.

 

[exjay82]

so i meant castor angle instead of pinion angle in the first post, and I misread u-joint for balljoint.

so.

1. What should the pinion angle be? 0?

2. how and where to measure for caster? (which direction the axle needs to be rotated) I hear people saying it needs to have positive castor and then people argue about which way is "positive"

can i measure off the top of the balljoint?

 

[GrimmJeeper]

Time to take it to a shop. You've asked 3 times about measuring off the top of the balljoint only to be told no each time yet you keep asking. I think you're in over your head here. No offence just stating what appears to be obvious to everyone but you.

 

[RCP Phx]

so i meant castor angle instead of pinion angle in the first post, and I misread u-joint for balljoint.

so.

1. What should the pinion angle be? 0?

2. how and where to measure for caster? (which direction the axle needs to be rotated) I hear people saying it needs to have positive castor and then people argue about which way is "positive"

can i measure off the top of the balljoint?

I always use my upper "ball-joint" to set my castor,works great.Most here work on their castor first(about 5-9* positive-top of the axle angled back towards the rear of the vehicle like this / ) and let the pinion angle be '"what it is".

 

[oblivion_twister]

pinion angle is plus or minus one degree of what the driveshaft angle is at the transfers case ouput. If transfercase ouput driveshaft angle reads 2 degrees and your pinion angle (read at the yoke) reads 5 degrees then you need to move each 1.5 degrees to match.

I doubt this is what you are asking. If you want to read caster (a front alignment steering angle of the ball joints in relation to an imaginary vertical line) then yes, you can read off the top ball joint, just keep in mind you need to be on a flat surface or measure the surface angle and compensate with the angle finder.

 

[RCP Phx]

pinion angle is plus or minus one degree of what the driveshaft angle is at the transfers case ouput. If transfercase ouput driveshaft angle reads 2 degrees and your pinion angle (read at the yoke) reads 5 degrees then you need to move each 1.5 degrees to match.

 

[RCP Phx]

That would be nice,but isn't achievable with a stock front axle.

 

[jeeperjohn]

I chased angles on mine for a couple years and I either had death wobble or bad vibes. In the end, out of pure frustration I adjusted my axle for a 0* pinion to driveshaft angle and low and behold, there was no death wobble. I can't explain it but I have very low vibes (mainly resulting from an inbalanced front driveshaft) and no death wobble. The only thing is thet the steering is a little darty but I can handle that. I also built an axle for someone and rotated the inner "c"s 5* and he reports perfect handling and no vibes.

 

[chris_amrein]

On this subject, can someone tell me what the stock pinion angle is on a low pinion housing and/or the relationship to caster angle? I.e. if your caster is 5 degrees what's your pinion angle? Or in Jeeperjohn's case with zero degree caster, whats, your pinion angle?