2nd Gen Non-Engine/Transmission Update on failure to obtain -.3 cross caster alignment spec

[Sojourner]

We installed a DSS, a DT track bar, Moog #K7396 adjustable upper ball joints with grease zerks (Ingalls Engineering will not have their re-designed adj. ball joints available for Ram 4x4s for another 4 or 5 months), and a Rough Country steering stablizer, but there is no major improvement towards acquiring the -. 3 cross caster spec that ace Mopar mechanic Brent recommends. As it stands now, we don't have enough adjustment available in the right side eccentric to get the -. 3 cross caster spec. I suspect this condition on my dually is largely a result of using the Mopar lowering kit for the rear suspension that helps in the pulling of a 5er level, but I cannot be sure. One thing's for sure, there is no longer a pull to the right. Instead I have a very slight pull to the left on crowned roads, but the truck tracks wonderfully straight on a level road, and I mean arrow straight. The steering input seems to be less, but still more than I think it should be. Right now it is handling and steering better than new with a very solid feel, the way it should have been in the first place. It is a great feeling. Next thing we're gonna do is install DT Pro Fab's lower control arms in order to have a wider range of caster adjustment, then I think we'll be able to get it to align to the -. 3 cross caster spec. I am hoping to not only eliminate or greatly reduce the pull to the left, but to also reduce the steering input. We will see. Oo.

 

[Turbo Tim 1]

This is pretty good info, I am planning on going through my front end very soon. My current pair of front tires only have 25k on them and they won't last too much longer. Of course the rear duals have 60k on them. I want to get as much information as possible, what's available, what are the best specs etc. things like track bar options (DT, Darrins 3rd gen update) Ball joint options, will the control arms from DT work with just a leveling kit? What are some problem areas in the second gen front end that get overlooked? Sometime this winter I want to redo the whole front end and put on 6 new BFG's and just the tires run about $1100 so I want to do it right. Give me more ideas. By the way I already have the DSS.

 

[Sojourner]

Here's the latest: we installed a 'mismatched' set of DT Profab's upper and lower control arms (uppers stock length, lowers 1/2" longer) in an attempt to get more caster adjustment. Using Brent's frontend alignment specs for the 2nd gen 4WD, here's the closest we could get:



*******caster camber

left******4. 7 0. 1

right*****4. 5 0. 0





cross caster 0. 2

cross camber -0. 1



The end result is that the truck still wanders much more than I care for, although I have hit stretches of road where it has tracked perfectly straight in 'hands off' mode for up to . 4 mile. As you can see we are 0. 5 degrees from obtaining the -0. 3 cross caster spec, so next we are going to try to eliminate the wander by adjusting the camber with the adjustable balljoints.



Anyone got any other suggestions? TIA

 

[NVR FNSH]

Maybe I'm missing something but how are the control arms changing cross caster? Isn't cross caster changed only by the adjustable ball joints? Otherwise you would have to twist the axle housing, correct?



Also, I'm not seeing how lowering the rear end would change the cross caster.



Brian

 

[Sojourner]

Maybe I'm missing something but how are the control arms changing cross caster?

The longer lower control arms provide for more range of caster adjustment in this situation.

Isn't cross caster changed only by the adjustable ball joints?

From my understanding, the caster adjustment is made by the eccentric cam bolts behind the axle. We installed the adj. balljoints in an attempt to give us more range of adjustment, which it did, just not enough to get us to the spec that Brent has provided. With the stock configuration control arms there was not nearly enough adjustment available on the right side to even get close to the -. 3 cross caster. The service mgr. at the shop I use, Dave at DT Profab, and I discussed this situation and figured we could get increased range of adjustment by installing a mismatched set of control arms.

Otherwise you would have to twist the axle housing, correct?

I'm not an alignment expert, that's why I pay competent pros to get the job done right with a 'lifetime alignment' deal.

Also, I'm not seeing how lowering the rear end would change the cross caster.



Brian

I'm just guessing that perhaps the lowering of the rear of the frame on the rear axle by 1 7/8" somehow affected the frontend geometry, but I could be mistaken 'cause I just don't know for sure. :{

 

[BKenny]

I not an expert but i would think when you lower the back you would gain positve camber. On old Vws poeple run caster shims in the frount when they lower the front end to cominsate (raked stance). I lowerd the front of mine and later lowered the rear after i lowerd the rear i noticed my turning radius got bigger. It was because i gained caster so im convused when i here that leveling the truck make the caster worst. Im planing on puting a Kore leveling kit on mine im still trying to learn about the suspention on these things

 

[jrobinson2]

On a stock Dodge 5 link front suspension a leveling kit does not decrease caster, it actually increases caster, the upper control arms are over 1" shorter than the lower control arms, this makes the upper arm follow a shorter arc as the axle drops and actually pulls the top of the axle back increasing caster. If the arms were equal length caster would not change and if the top arm were longer caster would decrease, if the axle was mounted on a single arm like the new ford super duty caster would decrease.



As to cross caster I highlighted Brents original explanation below.

Here's the problem:

Alignment programs (and service manuals I believe), give a wide acceptable range for front caster on the 4x4 Rams. I believe the range is 2 degrees to 5 degrees (if that's not correct, it's pretty close). The problem occurs when the alignment tech (independent or dealer) tells you that the measurements "checked out fine", just because they were in this broad range of acceptance. Caster readings that fall on either end of the scale are subject to caster shimmy, even though they are "acceptable". I had to align some 30 trucks and attend a 9 hour "Dodge Ram Chassis Dynamics Diagnostics" training session (fancy name, ehh?), before finding out that 3 degrees to 4 degrees is the optimal caster setting for 4x4 Rams that eliminates caster shimmy.

Below I will post what specifications I set Ram trucks to. First I want to give a little more info on correct Ram alignments so you can see if you had a job well done, The eccentrics on the lower control arms ARE NOT for individual wheel caster adjustments (even though our alignment machine says they are). The eccentric sleeves in the upper ball joints are for adjusting individual camber and total cross caster (difference in caster between two front wheels). This is why replacement eccentrics are positionable in eight different ways.

Once camber and cross caster are attained with the eccentrics, the lower control arm eccentrics are

then used to swing the caster readings into specifications. The two eccentrics must be swung in the SAME direction in EQUAL amounts. If they are not, it will create a setback condition (one front wheel further forward than the other).

FYI - Comparing between the two front wheels, caster will cause a pull to the smaller value and camber will cause a pull to the larger value. A truck set up with caster pulling in one direction and camber pulling in the other direction, can lead to a wandering truck; even though it is "in specifications"!!!!!!

If the eccentrics on the lower control arms of your truck are not pointing the same direction, the alignment was done incorrectly and the axle was "twisted" or "forced" into position to attain theacceptable values (seen them from the factory this way, go figure).

A correct alignment will set the truck up with a slight negative cross caster (truck has slight pull to left) to compensate for right hand road crown. Camber will be equal side to side slightly on the negative side. This will help maintain acceptable camber when hauling heavy loads, as the truck tends to lift in the front when towing. Camber will then fall slightly positive when towing.

Just because the alignment shop says "it's in specifications", that does not mean it is set up for proper performance and handling!!!!!!!!! Specifications (my personal settings for every Ram I align): all specs below are in degrees.





Left Wheel Right Wheel

--------------



Caster 3. 2 3. 5

Cross Caster -. 3



Camber -. 10 -. 10

Cross Camber 0. 0



Toe - standard specs, (maybe a little out if you tow a lot, they will pull in as the front end lifts up).



Brent

ASE Certified

Gold Certified Chrysler techre's the p the alignment shop says "it's in specifications", that does not mean it is set up for proper performance and handling!!!!!!!!! Specifications (my personal settings for every Ram I align): all specs below are in degrees.





Left Wheel Right Wheel

--------------



Caster 3. 2 3. 5

Cross Caster -. 3



Camber -. 10 -. 10

Cross Camber 0. 0



Toe - standard specs, (maybe a little out if you tow a lot, they will pull in as the front end lifts up).



Brent

ASE Certified

Gold Certified Chrysler tech

Jared

 

[BKenny]

Hm,good info

 

[mechanic]

On a stock Dodge 5 link front suspension a leveling kit does not decrease caster, it actually increases caster, the upper control arms are over 1" shorter than the lower control arms, this makes the upper arm follow a shorter arc as the axle drops and actually pulls the top of the axle back increasing caster. If the arms were equal length caster would not change and if the top arm were longer caster would decrease, if the axle was mounted on a single arm like the new ford super duty caster would decrease.



As to cross caster I highlighted Brents original explanation below.







Jared

10/4 on what Brent has outlined. One of the worst ripoffs in the business is F/E alignment. I think that most techs (there are not many mechanics anymore) do not understand the way a front suspension works and what caster and camber and toe-in really do and how they do it. And the factory specs are designed to save those warranty dollars, not make the vehicle drive well. Shops that use the spec range, are not really aligning front ends, they are just stopgapping the thing to get it through and out the door. It takes me about 1 1/2 to 2 hours to set up a front end, and get it to the point that I feel good with it. I know that many are faster then I am, and still do it right, but after all these years I am not as fast as I once was. However, the 15 to 30 min. alignment is highly suspect. Thanks for your post of Brents original post, it makes me feel good to know that there are still front end (And other systems) MECHANICS out there, and that my generation is not going to be the last ones.