Steering Self Centering Issue

[RicB]

I have an 86 X1/9 that I backdated to 74 bumpers, etc. At the time I cut one coil off of the front springs to get the ride height back down. I don't drive the car a lot (other cars in the stable and it's hot out here in Texas!) and lately because of a bad steering rack which has now been replaced plus inner and outer tie rod ends along with a four-wheel alignment at my local race shop. They used alignment specs from the 79-89 model. Now the steering (EDIT: on wheel movement up to about 90 degrees off center) doesn't return to the center when I let go of the wheel, I have to steer it back to a straight line. I don't recall this being the behavior prior to this alignment. Would the alignment specs for a 74 with its lower front ride height be that different? Here are the current measurements:

Front
Camber Left: -1.1 Right: -1.2
Caster Left: 6.4 Right 6.9
Toe Left: 3.1 Right: 3.2
Steer Ahead: -0.01

Rear
Camber Left: -0.8 Right: -1.1
Toe Left: 5.8 Richt: 5.8
Thrust Angle: 0.00

Thanks.

 

[Dr.Jeff]

Lack of "self centering" is a castor issue. Castor on the X is determined by the trailing arm (thrust rod, torque arm, brake strut, etc). The rubber bushings on the forward end of that rod will determine the castor, which otherwise isn't adjustable. Those rubber bushings wear and become disfigured very quickly. Therefore they should be new before the alignment is done (this is one place where I think using urethane bushings is worth doing for a "street" X). Then the rods can be adjusted by adding shims around the bushings as needed. You might determine the condition of these bushings first. Then see if the alignment shop can change the castor accordingly.

 

[JimD]

Here is the shop manual page for the X suspension info. The specs are the same for all years. I found a note in one thread stating that the specs should be taken from later manuals (79 0n) because of a typo in the specs in the 74 - 78 manual.

Cutting the springs will change the existing alignment measurements probably taking the car out of spec, a subsequent alignment should bring the car back into spec.

 

[Ics19]

because of a bad steering rack which has now been replaced

After you had the rack replaced, but before you had the shop do the alignment, was the steering centering ok at that point? Could the "new" rack be bad as well - just a thought, but possibly the rack adjustment doesn't have the necessary play so it's binding?

 

[RicB]

After you had the rack replaced, but before you had the shop do the alignment, was the steering centering ok at that point? Could the "new" rack be bad as well - just a thought, but possibly the rack adjustment doesn't have the necessary play so it's binding?

Interesting thought. The shop replaced the rack and did the alignment. And I'm pretty sure I did not experience this issue prior to rack replacement.

 

[Dr.Jeff]

After you had the rack replaced, but before you had the shop do the alignment, was the steering centering ok at that point? Could the "new" rack be bad as well - just a thought, but possibly the rack adjustment doesn't have the necessary play so it's binding?

Good point, definitely possible. I've inadvertently over tightened the adjustment on a steering rack in the hopes of compensating for wear (rather than rebuilding or replacing it). And it can make the rack so stiff that it won't easily self-center.