Quick caster adjustment question

[RussJ]

In looking over my front suspension I noticed that my caster adjustment cams are not adjusted equally side to side. Should they be? They're not really even close. Is this normal?

 

[TowPro]

In looking over my front suspension I noticed that my caster adjustment cams are not adjusted equally side to side. Should they be? They're not really even close. Is this normal?

If the tires are wearing good, its OK.

 

[Jeepstang]

caster will not cause tire wear

the only way to find out for sure is to put it on an alignment machine

both sides should be in factory specs and within half of a degree of each other

 

[rbattelle]

How can each side of a solid axle be set to different caster (unless the axle ends were welded wrong at the factory)?

Do I have the wrong definition of caster?

Ryan

 

[RussJ]

How can each side of a solid axle be set to different caster (unless the axle ends were welded wrong at the factory)?



Do I have the wrong definition of caster?



Ryan

Very good point! I guess I should have thought of that. It just struck me as odd that the cams would not be adjusted equally. Still not sure why they would'nt be! It must affect something, right? Am I wrong? I only bring this up because the other day I experienced what I believe is the notorious "Death Wobble".

I've checked over the front end, and everything looks O. K. With the exception of the cams and the BFG's.

 

[FGoodwin]

Alignment rack is the only way to know. In regard to the death wobble, check your Ball Joints, especially the uppers, I believe there is a TSB out there. I had it after doing a lift, I tried to correct it by adding positive castor, did not help a bit. Replaced the ball joints and viola, no more wobble. Castor does not cause tire wear, just steering issues. The castor adjustment may very well be diff. side to side in regards to placement of the cams. The axle tube may be attached to the control arms at diff. angles, or maybe the control arms themselves might be of diff length, many diff possible combos of problems, alignment rack is only way to tell.

 

[lil red cummins]

it is not unusual to have positive caster on one side and negative caster on the other. there are a lot of variables.



suffice it to say. caster affects whether or not your vehicle pulls left or right, while driving in a straight line on level ground. if you do not have a pulling problem, do not mess with the caster.



if your vehicle wanders or does NOT have a tendency to straighten it self out after turning, you probably don't have enough caster.



BTW, i have never paid a penny for an alignment on any vehicle in my life. i am 52. i was a professional mechanic for many years and worked on hundreds of cars, trucks and school buses.



front end alignment - the quick easy way... .



TOE IN can be adjusted with a simple home made gauge. this is the adjustment mainly responsible for tire wear.



CASTER can be adjusted by trial and error to remove pulling. add caster to reduce wander.



CAMBER is a visual adjustment and when adjusted to line up with the rear tires, i. e. vertical tilt, you are probably good enough for 98% of driving situations. yes, road course racing and oval track racing are two different stories.



for all those trained by a "professional" who say you must use a machine, i GOT all this information from someone who taught this stuff back in 1969.



save your money, learn the basics of steering geometry.



my . 02



jim

 

[Bob V]

it is not unusual to have positive caster on one side and negative caster on the other. there are a lot of variables.



suffice it to say. caster affects whether or not your vehicle pulls left or right, while driving in a straight line on level ground. if you do not have a pulling problem, do not mess with the caster.



if your vehicle wanders or does NOT have a tendency to straighten it self out after turning, you probably don't have enough caster.



BTW, i have never paid a penny for an alignment on any vehicle in my life. i am 52. i was a professional mechanic for many years and worked on hundreds of cars, trucks and school buses.



front end alignment - the quick easy way... .



TOE IN can be adjusted with a simple home made gauge. this is the adjustment mainly responsible for tire wear.



CASTER can be adjusted by trial and error to remove pulling. add caster to reduce wander.



CAMBER is a visual adjustment and when adjusted to line up with the rear tires, i. e. vertical tilt, you are probably good enough for 98% of driving situations. yes, road course racing and oval track racing are two different stories.



for all those trained by a "professional" who say you must use a machine, i GOT all this information from someone who taught this stuff back in 1969.



save your money, learn the basics of steering geometry.



my . 02



jim

Jim I am about the same as you, Did a lot of alignments in my day. Most of the alignment machines are out of calibration enough that you can do a better job with a tape, IF you know what you are doing.

You can not change the caster from side to side one the dodge 4X4 strait axle tricks with the caster cams, all that will happen is that you will distort the bushings. The cams can be different from side to side do to manufacturing tolerances. If you think that one side is out you would have to loosen that bolt on that side and rotate it till the cam is not rubbing against either side if the cam guide , what you want to do is get it so there is no preload on the bushings

 

[rbattelle]

It's good to hear you guys discussing alignments without the need for an alignment rack, because it's something I'd like to do myself.

Alignment racks have those swivel pads under the front wheels for toe adjustment. How do you go about adjusting toe with the vehicle on flat ground, with the weight holding the wheels from turning easily?

Ryan

 

[lil red cummins]

ryan:



i will have to post a pic of my toe in gauge. unfortunately it is at home today.



it is a very simple device made with 3/4" galvanized pipe, a 1" union and 2 vertical pieces, along with a "gauge". one end is fixed, the other end slides to accomodate different track width vehicles.



i will be glad to give you dimensions once i get it in my hands.



to adjust toe in:



1. pull straight forward, that is, your steering wheel should be in its "normal" straight down the road position. (if your steering wheel is not "centered" now, don't worry. read on). you don't need to drive more than 10 feet forward. your tires normalize quickly. make sure you are on level ground front to back. if there is any twist in the frame, it may alter the reading.



2. take a reading with the toe in gauge. this is better as a two person operation. the reading is made on the widest point of the tire. one measurement in front, one measurement in back. height off the ground must be the same. determine if you need alignment. a normal toe in is no more than 1/8" and i normally adjust for 1/16" or right on zero.



VERY IMPORTANT. make your final adjustment based on tire wear. in other words, if your tires are wearing more on the outside, there is too much toe in. if your tires are worn more on the inside, it is too far toed out.



also, it is not unusual for the right tire to be worn more than the left tire, especially on a vehicle that regularly only carries a driver.



3. if adjustment is required, the first thing to do is determine if your steering wheel is straight. depending on your tie rod end adjustment style, you can put your steering wheel back on center depending on which tie rod you adjust. this is a lot easier to show to someone than to explain.



4. make an arbitrary adjustment, maybe 1/2" turn of the tie rod end or joint or rack end shaft. (depends on design)



5. now, just back up the truck about 20 feet and pull forward to your original location, take notice of whether the steering wheel is straight(er) than before.



6. using the toe in gauge, take another reading. you should now know if more adjustment is necessary. you should also know how much 1/2 turn actually changed the toe in.



7. if you have your toe in where you desire, do a road test and make sure that the steering wheel is straight. the position of the steering wheel is somewhat succeptable to road crown and tilt. you need to be aware of the road style before determining wheel center. if you believe you made an error in selecting which tie rod to adjust, simply take back out the adjustment you made, and make the equal adjustment on the other side.



this is a good start, hope it helps



jim

 

[lil red cummins]

well i finally got around to taking some pics.



overall length of the main 3/4" galv. pipe section is 88"



the vertical rise is around 12-1/2" from the ground



the left end (in the photo) is fixed and welded. there is a 1/2"-13 carriage bolt with the head slightly flattened, for a locator. it also has a base to keep the device standing upright.



the moveable end is a 1" galv. coupler, slightly machined out. it is crossed drilled and tapped for 3/8"-16 bolt with "wing" style head. i got this off of an old office chair.



the gauge itself is a piece of 1/2" round stainless with 3 grooves machined 1/16" from each other. there is a washer welded on each end so that it does not slip out of the sleeve. (i forget what the sleeve is made out of, but it just clears the 1/2" rod). you always start on the middle groove.



when i take a reading, i push in on the gauge and pull back on the riser a few times to make sure that when it springs back, it reads the same.



if you have any questions, please let me know.



jim

 

[rbattelle]

Clever! The older I get, the more I appreciate homemade tools.

Ryan

 

[JHardwick]

That gage should work fine, however, I prefer the pizza cutter/pointer method to eliminate any sidewall or wheel irregularities.

 

[nickleinonen]

How can each side of a solid axle be set to different caster (unless the axle ends were welded wrong at the factory)?

Do I have the wrong definition of caster?

axles will bend... . you can adjust the camber of a solid rear axle if you want something other than 0°. just cold press the tubes. the axle shafts will handle the flex

 

[lil red cummins]

That gage should work fine, however, I prefer the pizza cutter/pointer method to eliminate any sidewall or wheel irregularities.

good point about sidewall irregularities!!



tires that have bulges or raised white letters can be troublesome. you have to make sure you have the same type of surface front to back.



when in doubt, roll the truck forward so that the tire rotates 90 degrees and take a second reading.



jim

 

[THUREN]

Lots a good info from Jim, but I wanted to point out a few things too...



Caster, believe it or not, can have an effect on tire wear but not like you would think. If you are driving fast on a lot of very twisty roads, more caster will introduce a negative camber effect while turning helping keep the outside edges from rolling. .



I have found that some of these trucks have issues with the rear axle placement not being true, so this would cause the needed "off true" front axle cam positions. It does often introduce bind it the bushings but that is ok, and has to happen to correct pull in a lot of trucks. With the cams un ballanced, they are being used as wheelbase adjusters which corrects irregular dimensions. So with unballanced cams you are not actually introducing "cross caster", but rather fixing the wheelbase. .



HTH,



Don