Front and Rear End Alignment Questions...

[1-ton]

The Alignment on my Crew Cab has a very "neutral" feel to it (i.e. not much forward directional stability). I think this could be due to not enough positive caster on my Dana 60. Some of the positive caster was probably lost when the 4" lift was installed. I have heard that there are wedges that can correct this, but wouldn't this increase the front drive shaft operating angle?



Also, I had a chance to drive directly behind my Crew Cab one time while my wife was driving it, and I noticed the truck had a slight amount of "dog legging". This would indicate that the rear axle of my truck is a little out of alignment. I have looked very closely at the rear axle, and it shows no sign what so ever of shifting out of place. I think the reason for the rear axle mis-alignment is from the cheap cast iron lift block saddle pins not lining the rear axle up properly.



Any thoughts or information on this...?

 

[1-ton]

ttt

 

[1-ton]

I guess not too many people know much about this subject.

 

[MTBLAZER89]

I don't know squat about castor, all I know is toe-in procedures. As far as the front to rear the rear axle is ~3" Narrower causing it to look dogtracked when looking from behind..it's normal to appear that way.

 

[Afireinside]

I would look at steering components because a 4 inch lift should not affect castor maybe kingpins?As far as the rear I think all chevys look like that and its because the rear axle is not as wide as the front HTH

 

[Fierospeeder]

It would be easier to tell how much your rear is off by putting it on an alignment machine.


I do remember hearing about caster shims for the axle. I do know they sell them for the bug community when the car is lowered and additional caster needs to be added. Usually, caster is only increased by 1 or 2 degrees. I have read that you can compensate the drive line angle by dropping the transfer case. The problem with solid axles is that there are no real adjustments besides toe.

 

[biere]

I have a crew cab and the easiest thing I can think of for you to do is to start off drawing a basic pic of where things were before the lift. Then draw the changes that came with the lift.

If you are wanting to add wedges they are going to roll the axle a certain way and you should be able to do these basic drawings and see how your driveshaft angle is changing.

Off hand I can't picture this well enough to give a solid axle, but my crew cab is stock so that is mostly why I don't know since I have not done anything yet.

As for the dog tracking, I bought some tires at one of the places that says they will do an alignment check if you buy all 4 tires. And the guy told me they could not adjust most of the things on my truck since they don't deal with big pickups much. But I got a 4 wheel baseline and kept the printout so I would know if things needed to be adjusted or not.

I would say if the problem bothers you then you may want to talk to a shop that works on medium duty and heavy duty trucks. They are some of the best folks to work on one ton trucks because they often see similar designs everyday. I used to work in a spring shop and that is the only place I would trust to line up my crew cab if and when it needs it. And I mean most any spring shop. They work on trucks where tire wear is very important and they consider our trucks tiny so it is sort of an easy job. You may wind up paying a bit, depends on what they charge.

Overall, before replacing your blocks in the back I would measure the new ones to compare and see if they will make a difference. You may be playing a game where the blocks need to be custom made or just adapt what you have to work it out.

Or see if there is a good 4x4 shop in your area. Overall I don't trust dealers since they do not try to be very precise in most cases and the local garages often can't fit a full size 3+3 into their bays let alone have the tools and experience to work on them right.

 

[1-ton]

The problem with my truck is that it has very little directional stability. If I turn my wheel at a decent speed, it will stay turn for quite a long distance, until it returns itself to the straight ahead position. When a front suspension has the proper amount of positive caster, it will return itself to the straight ahead position reasonbly quick without having to physicaly pull it back to straight ahead with your hands.

I also think the Thrust Angle on my differential is off a little bit. When I follow behind my truck, I can see the left side of my truck. Kind of like it is tracking sideways. There is only one thing that keeps solid rear axles in line, and that is the saddle pins, thus is is the only problem that could exist. I have noticed the "dog legging" condition on a number of trucks that are lifted with blocks.

 

[BLZN4FN]

The rear is real easy. If you think its dog leged take a tape measure from the
center of the hub to the body (if you have not cut up the panels) it should be the same ft to rear on both sides. It is not uncommond to have a bad lift block or a broken pin. If the block is ok, The axle pins are aligned up you may have a bent frame.

Now for the Ft end.
Have you had it aligned? and what are the specs on caster/camber/toe?
Putting on a 4inch lift should not create any problems. Did your lift springs have degree shims? The degree shims will help with your caster concern it takes the axle and rotates the pinion up. Most shins are approx 1-2 degrees
which is more than enough to put you in positive caster which is a good thing
but this can only be done in moderation to much caster will cause a loose kinda feeeling. One thing I have found on the wheel returing to center on these old trucks it helps but you will not get it to do a full return on it own
Its just a bad design. I hope this helped a little get a alignment done on you truck to see where your at and let me know what the specs are and from there I can tell you where you need to start to get more or less aster and or toe.