How to adjust caster?

[Chris]

I know how to adjust the caster with my new control arms. What I am trying to figure out though is the process for doing so.

I'm assuming that the vehicle needs to be completely flat on the ground in order to measure the caster angle and pinion angle, yes?

So, let's say I install these adjustable control arms. Do I then have to put the wheels back on, remove the jack stands and get the vehicle on the ground before I can measure my caster / pinion angle?

Let's say I do that and find that the angle is slightly off, do I then need to jack the vehicle back up, pull the wheels back off and then re-adjust my control arms to change the angle again slightly. Then I assume it's wheels back on, vehicle back on the ground and then measure the angle again?

Seems like a lengthy process but I'm not sure how I could correctly get the pinion angle / caster dead on when the vehicle is up on jack stands with the wheels off.

 

[Jerry Bransford]

Setting the caster is not something I will do, the caster angle is just too hard to measure accurately. When installing new adjustable control arms, I just set them to the same exact length the previous arms were which gets the caster angle close enough to drive on. Then I take it to a 4x4 shop that has an alignment rack (not a standard alignment shop) and have them check and adjust the caster angle as need be. A standard alignment shop won't mess with removing the control arms and adjusting their lengths but a 4x4 shop with an alignment rack will.

 

[Chris]

Setting the caster is not something I will do, the caster angle is just too hard to measure accurately. When installing new adjustable control arms, I set them to the same exact length the previous arms were which gets the caster angle close. Then I take it to a 4x4 shop that has an alignment rack (not a standard alignment shop) and have them check and adjust the caster angle as need be. A standard alignment shop won't mess with removing the control arms and adjusting their lengths but a 4x4 shop with an alignment rack will.

That was my thought, I figured that a local alignment shop probably won't touch adjustable control arms. I'd have to find a local 4 x 4 shop.

I still intend to do this, I think I was mostly just curious about how you set the caster per my original post.

 

[Bermudacat]

Unless it was causing problems, like a wobble, I'm not sure what the fuss is.

Good read on suspension tuning; http://www.amazon.com/gp/product/0912656468/?tag=wranglerorg-20

 

[Chris]

Unless it was causing problems, like a wobble, I'm not sure what the fuss is.

Good read on suspension tuning; http://www.amazon.com/gp/product/0912656468/?tag=wranglerorg-20

I had no choice but to set it since I installed a set of Currie adjustable control arms.

 

[Bermudacat]

Right.

If my ds angle seemed good and I had no wobble, I would have no worries. My uppers are adjustable but my lowers are fixed. IIRC when I did replace the uppers, some time after the lowers, I just approximated the distance of the stock uppers. If your stock pinion angle works with your ds, then the caster would also be fine?

I've always done my own alignment(s). With basic tools and knowledge it is really quite simple.

I think installing the suspension is way more work than doing the alignment when you are finished.

 

[Jerry Bransford]

Yep if I'm not getting any front driveshaft vibration and I have good return-to-center after completing a turn, I would not mess with the caster angle. It's not a critical angle... there just has to be enough so the steering wheel returns to center and not so much it causes vibrations due to an excessive pinion angle.

 

[Chris]

We'll see... Finished up the Currie suspension install so I'll be taking it out today and hoping that all my angles and everything are good to go. They should be, I measured them to be right there they need to be,

 

[Bermudacat]

I think 1/8th to 3/16th works pretty well for toe in.

 

[Chris]

I think 1/8th to 3/16th works pretty well for toe in.

Yep, I usually go with 1/8 to 1/16.

 

[Adms01TJ]

Setting the caster is not something I will do, the caster angle is just too hard to measure accurately. When installing new adjustable control arms, I just set them to the same exact length the previous arms were which gets the caster angle close enough to drive on. Then I take it to a 4x4 shop that has an alignment rack (not a standard alignment shop) and have them check and adjust the caster angle as need be. A standard alignment shop won't mess with removing the control arms and adjusting their lengths but a 4x4 shop with an alignment rack will.

Hi guys,I know this is an old thread, but I am in the process of buying adjustable control arms. What ACA's are most likely going to help in getting the front end alignment fine tuned.
A little back round. Last year after getting an alignment done at a Mavis shop I drove the Jeep a half a mile and the steering wheel started shaking like it was possessed. This had never happened prior to the alignment so needless to say I was not too happy. Brought the Jeep directly back to the shop that performed the alignment and the technician had forgot to tighten the nuts for the OME steering stabilizer. The manager did mention that there was a lot of play in the steering wheel about 2" before the wheels started moving and that the trackbar had too much play on the frame side. He recommended a local shop that is reputable to help with getting my front end fixed. Moving ahead I ordered a new steering linkage from Mopar and a PSC HD steering gear box, psc power steering pump and pulley and a new serpentine belt. The jeep currently has stock control arms that were replaced within the last 5k miles and has the DPG offroad Old Man Emu ultimate lift kit. I also rebuilt the JKS trackbar at the same time that the steering was done.
Knowing whats on the Jeep what would you recommend as far as adjustable control arms for alignment purposes??? Thanks in advance for your help...

 

[bobthetj03]

Hi guys,I know this is an old thread, but I am in the process of buying adjustable control arms. What ACA's are most likely going to help in getting the front end alignment fine tuned.
A little back round. Last year after getting an alignment done at a Mavis shop I drove the Jeep a half a mile and the steering wheel started shaking like it was possessed. This had never happened prior to the alignment so needless to say I was not too happy. Brought the Jeep directly back to the shop that performed the alignment and the technician had forgot to tighten the nuts for the OME steering stabilizer. The manager did mention that there was a lot of play in the steering wheel about 2" before the wheels started moving and that the trackbar had too much play on the frame side. He recommended a local shop that is reputable to help with getting my front end fixed. Moving ahead I ordered a new steering linkage from Mopar and a PSC HD steering gear box, psc power steering pump and pulley and a new serpentine belt. The jeep currently has stock control arms that were replaced within the last 5k miles and has the DPG offroad Old Man Emu ultimate lift kit. I also rebuilt the JKS trackbar at the same time that the steering was done.
Knowing whats on the Jeep what would you recommend as far as adjustable control arms for alignment purposes??? Thanks in advance for your help...

Currie, Savvy, or Metal Cloak arms would be my suggestions. If you get double adjustable arms, it's much easier and less labor intensive to fine tune the lengths. After your alignment, what was your caster specs? What size tires are you running?

 

[ac_]

Hi guys,I know this is an old thread, but I am in the process of buying adjustable control arms. What ACA's are most likely going to help in getting the front end alignment fine tuned.
A little back round. Last year after getting an alignment done at a Mavis shop I drove the Jeep a half a mile and the steering wheel started shaking like it was possessed. This had never happened prior to the alignment so needless to say I was not too happy. Brought the Jeep directly back to the shop that performed the alignment and the technician had forgot to tighten the nuts for the OME steering stabilizer. The manager did mention that there was a lot of play in the steering wheel about 2" before the wheels started moving and that the trackbar had too much play on the frame side. He recommended a local shop that is reputable to help with getting my front end fixed. Moving ahead I ordered a new steering linkage from Mopar and a PSC HD steering gear box, psc power steering pump and pulley and a new serpentine belt. The jeep currently has stock control arms that were replaced within the last 5k miles and has the DPG offroad Old Man Emu ultimate lift kit. I also rebuilt the JKS trackbar at the same time that the steering was done.
Knowing whats on the Jeep what would you recommend as far as adjustable control arms for alignment purposes??? Thanks in advance for your help...

This is exactly why I do it myself. Unlike Jerry, I have more time than brains. I will take a week to get it perfect rather than keep dropping back off at the alignment shop more than once. I had a Toyota 4x4 and took it in for a routine alignment, and I had to bring it back 3 times before they got it right and even then I still wasn't confident. It is much harder to do yourself. but can be done. Longacre Racing among others sells nice tools so you can do it yourself. Or just a Dewalt tape, and an angle gauge will get you in the ball park.

Realistically, even if you take it to the shop, and they do get it perfect the first time you take it off road it is off. I mean if you went one day got an alignment at the shop, and went off road, and take it back it wont be exactly the same the next day. Even if it is a quarter inch off. The fact is you feel comfortable taking it to the shop then you leave and as long as your steering wheel is straight or your tires don't wear uneven you are happy. So I figure the same thing. If get the tape out and measure it all out, and get it close, and it drives straight and tires wear right and the steering wheel is right, it is close enough for the girls I go out with.

I don't have time to deal with the jack hats that are supposedly experts at the shops with their fancy machinery they have no idea how to work if you have made any mods at all with.

 

[Adms01TJ]

Currie, Savvy, or Metal Cloak arms would be my suggestions. If you get double adjustable arms, it's much easier and less labor intensive to fine tune the lengths. After your alignment, what was your caster specs? What size tires are you running?

Hi Bobthetj03
Left Front Tire: Caster= 4.9 degrees// Camber= -1.6 degrees// Toe= -2.63 degrees.
Right Front Tire: Caster= 5.4 degrees// Camber= -0.6 degrees// Toe= 1.07 degrees

Left Rear Tire: Camber= -1.3 degrees// Toe= 0.90degrees
Right Rear Tire: Camber= -0.3 degrees// Toe= 0.26 degrees

Are you suggesting I get all 8 arms or just the front 4 double adjustable? What is going to be more helpful when doing an alignment? If I should just bite the bullet and get all 8 than I will do that.. but if i can save a few hundred and just go with the front double adjustable and be able to get the alignment close... that would be nice.. thanks again for everyone's input...

I am running 33" tires
Thanks..

 

[bobthetj03]

If you are just interested in adjusting you caster, then just get the front uppers/lowers. You want your caster to be closer to 6*, but not so far as to induce front drive line vibes. Pinion angle is king.

 

[jeepndogs]

I would be checking for a warn hub bearing or ball joint or joints on the left front. You need to do a dry steer test. The camber split shows something could be bent or worn. Also make sure the tire pressure was even in all tires when they did that. Both front and rear have a degree split on camber. It’s a solid front axel so you may not get the caster even on both sides without putting a control arm in a bind.

 

[Jerry Bransford]

Hi Bobthetj03
Left Front Tire: Caster= 4.9 degrees// Camber= -1.6 degrees// Toe= -2.63 degrees.
Right Front Tire: Caster= 5.4 degrees// Camber= -0.6 degrees// Toe= 1.07 degrees

Hopefully those aren't after the alignment. Toe-in should be .15 degrees per side for a total of .3 degrees toe-in between the left and right sides. +/- .06. You have 3.7 degrees of toe-in which is excessive. Caster should be at or very close to 6 degrees for 33" tires. Camber is fixed unless you replace your ball joints with adjustable ball joints (not usually needed or done).

Your shaking steering wheel could be caused by the excessive toe-in, it is however often triggered by a front tire that is not balanced precisely enough. What will NOT cause that is a steering stabilizer bolt that was too loose. A steering stabilizer can only mask that symptom, it can never be the actual cause of shaking. You should be able to drive without a steering stabilizer and not have any shimmy at the steering wheel when everything else is tight/adjusted/tires in good balance.

 

[Adms01TJ]

Good to know.. Thanks Jerry..
Those numbers are before the alignment. I did not want the "mechanic" doing any adjustments. He was in over his head I could tell.
Good to know about the steering stabilizer. I will bring it in to EVB in Danbury, CT. They are a reputable 4x4 shop. I am going to order up a set of the MC double adjustable control arms and make sure they balance all of the tires. Thanks everyone for the input.. I will update everyone with the alignment results after the adjustable control arms are installed and aligned.
Mt friend who I bought this Jeep from is trying to get me to abandon my TJ and sell it for a JK 4 door Rubicon.. He has crossed over to the dark side and is trying to bring me with him... He is trying to sell the 'comfort' factor.. thats why I have a 2014 Honda Accord for my DD.
These issues are what make owning a TJ fun.. To discuss it with intelligent folks and figure out what the issue is and not having a 400 plus a month payment is worth it to me.. Plus I love the TJ and always have since I was 20 years old.. It is what a Jeep is supposed to be...

 

[Longhorn84]

Hopefully those aren't after the alignment. Toe-in should be .15 degrees per side for a total of .3 degrees toe-in between the left and right sides. +/- .06. You have 3.7 degrees of toe-in which is excessive. Caster should be at or very close to 6 degrees for 33" tires. Camber is fixed unless you replace your ball joints with adjustable ball joints (not usually needed or done).

Your shaking steering wheel could be caused by the excessive toe-in, it is however often triggered by a front tire that is not balanced precisely enough. What will NOT cause that is a steering stabilizer bolt that was too loose. A steering stabilizer can only mask that symptom, it can never be the actual cause of shaking. You should be able to drive without a steering stabilizer and not have any shimmy at the steering wheel when everything else is tight/adjusted/tires in good balance.

Old thread but I'm confused on why caster is different on the front and if that's a concern or not, I realize that it is not adjustable since it's a solid axle but everyone talks about how caster and pinion relate but what caster do you use, is it that average between the two sides? And by the way, when I measured mine I had almost 3-4 degrees different castor from right to left.

 

[freedom_in_4low]

Old thread but I'm confused on why caster is different on the front and if that's a concern or not, I realize that it is not adjustable since it's a solid axle but everyone talks about how caster and pinion relate but what caster do you use, is it that average between the two sides? And by the way, when I measured mine I had almost 3-4 degrees different castor from right to left.

I set my caster indirectly by setting my pinion angle. I check my pinion angle with a magnetic digital angle finder on the machined flat spot next to the diff cover. The low pinion Dana 30 has approximately 12 degrees between the pinion angle and the caster angle, so if your pinion is pointed 6 degrees up, you'll have 6 degrees of caster. If your pinion is 4 degrees up, you'll have 8 degrees of caster.

Manufacturing tolerances put this probably plus or minus a degree, but it should get close enough that if you don't have any vibes after, and you still like what you have with return-to-center, it's good to go. You can get more accurate if you go to a place like Brakes Plus, who do free alignment checks (they charge you if you have them adjust anything). That gives you a baseline, so you can go home with your angle finder and if you want another degree, just adjust to add a degree to whatever your angle finder says you have. Write down the difference between their measurements and yours so you know the offset if you have to do it again.