This article originally published in Issue 53 of the Turbo Diesel Register.

From the Shop Floor

SECOND GENERATION HANDLING
AND SUSPENSION PROBLEMS, OPTIMAL ALIGNMENT
SPECIFICATIONS AND TECHNIQUES
by Andy Redmond

In Issue 46 we discussed the wear of suspension components and a resulting wandering Turbo Diesel. We continued on related topics in Issue 47 as we discussed the addition of a steering gear stabilizer bracket and steering gear adjustment and replacement. For this issue, I would like to share a few suggestions to help you fine tune the handling of your Turbo Diesel. Additionally, I will briefly recap the Issue 46 and 47 columns and discuss feedback from other TDR members on these modifications.

In Issue 46, I discussed adding the Solid Steel Track Bar Retrofit kit to Second Generation, four-wheel drive Turbo Diesels. The benefits of the parts retrofit include tighter road feel, less wander and no more “death wobble” (at least in my case). Most of us are familiar with the death wobble, but it bears mentioning again. It is violent caster shimmy where the tire and axle shake after striking a pothole, un-even road surface or bump. This usually involves the right front wheel. We learned that a worn track bar can allow the axle to have some side to side movement (detrimental to maintaining proper alignment) and this likely contributes to the wobble. Let’s tackle front wheel alignment, as replacement parts were necessary according to the prior articles to maintain proper alignment specifications throughout the suspension travel. Please note: when suspension adjustments or repairs are made, the vehicle should always be realigned.

First, some alignment terms should be defined.

Toe: The amount that either front tire points inward (positive toe) or outward (negative toe) which is stated in degrees or fractions of an inch. Too much positive toe and the outside of the tire wears, too much negative toe and the inside will wear.

Caster: The amount the upper ball joint, pivot or kingpin is rotated ahead of vertical centerline or back beyond vertical. For illustration, let’s imagine looking at the side of the front wheel. Let’s also imagine that a clock face is painted onto the tire with 12 o’clock and 6 o’clock marking our vertical line or center point. Caster is expressed in a positive or negative manner by the rotation of the upper joint (12 o’clock) towards 10 o’clock position or towards 2 o’clock. It is also expressed in degrees or fractions of an inch.

Excessive positive caster can cause additional wear on suspension components, although proper amounts help with direction stability. Excessive negative caster makes steering effort easier at the sacrifice of directional stability. Both can have some effect on camber during suspension travel. Cross caster: The amount of caster difference in the left front and right front wheels. Often a slightly larger value is used on the right front to compensate for the crown in the road. Upset the balance too much and the vehicle usually pulls towards the larger numeric value.

Camber: The measurement of how much the top of the wheel tips in towards the frame (negative camber) and how far it tips away from the frame (positive camber), with zero camber being a vertical centerline.

Cross Camber: The measurement of the difference between the left and right side camber values. And now, my preferred alignment specifications for a four-wheel drive truck (with thanks to Brent, an ASE and Gold Certified Chrysler technician).

These specifications are close to most DC service manuals. My opinion is that camber and toe may be a bit aggressive for members who do not use the Turbo Diesel at near loaded capacity. I can only assume that once the truck is fully loaded the camber specs somewhat zero out. Should you desire to align your truck with its load or your trailer, you require the service of a heavy truck tire/alignment center that has a drive through bay. This too is likely preferable if your truck is loaded most of the time.

Most alignment shops will perform a four-wheel alignment. The values printed from the alignment shop can give some meaningful data. The number may point to poor caster, which can be corrected by shimming the axle at the spring attachment point. It might also point to a misaligned rear axle. This could be due to a collision or worn spring bushings. But the rear axle does not typically require alignment, as there aren’t any adjustments that a shop can perform.

A rare exception would be corrections to thrust angle and rear axle alignment. The rear axle, although mounted perpendicular to the frame rails, is designed to offer parallel geometry to the frame. If it is not, then the axle is crooked and the rear end of the vehicle may “dog track.” Although the springs, blocks and mounts are doweled for alignment, small adjustments can be made. Correction involves the U-bolts being loosened and shifting the axle slightly fore or aft to square it back to the frame. If these adjustments do not correct the problem, a qualified frame shop should measure the frame for irregularities and/or an axle shop will have to check for a bent axle tube.

Most front wheel alignments include resetting the toe. The four-wheel drive Turbo Diesel does not have any provision to adjust camber, only toe and caster. The alignment results routinely show that the caster parameters are about 2 to 4°. Guess what? If it falls in that range, wanna bet the caster didn’t get moved? Still doubt me? Go look at the alignment report “before and after.” Did the alignment technician adjust the caster? Unless you asked for it, I’m guessing no. Or they may have said, “I can’t adjust the caster to 3.5 degrees!” What gives, as I’m suggesting 3.2 to 3.5°? On most ’94-’99 Turbo Diesel four-wheel drive trucks the factory eccentrics in the lower trailing arm won’t allow for much more than 2.8 degrees of positive caster. Let’s present a solution.

Ingall’s Engineering (located in Colorado) specializes in the manufacture of alignment components. They do not sell to individuals, only tire shop product distributors, like McGee Paris Rubber Supply (Southwestern States) or through Ascot (Georgia based).

Ingall’s makes a slick product for the ’94-’99 Turbo Diesel called an adjustable ball joint eccentric sleeve, part number 532 or 53200 (Ascot), suggested retail price of $45. The eccentric sleeve allows for caster and camber adjustment, which the alignment tech can then set to the preferred settings. It fits in place of the fixed alignment sleeve that resides on the upper ball joint stud in the spindle, which is retained by the upper ball joint nut and cotter key.

An assortment of front end parts.	Ball joint with non-adjustable camber/caster sleeve.

Ball joint thread protector that broke the taper so OEM sleeve can be pulled.	Old eccentric sleeve (upper). Upper pivot point as found on ‘00-’02 trucks.	New adjustable sleeve installed (lower).