I've been there on my tube frame 510 racecar. It totally screws up the way the wheels react to steering wheel input.
Here is why:
U-joints working at an angle transmit their rotational speed input to output with a speed-up/slow down within one rotation. The more extreme the angle, the higher the slow/fast differences will be. To reverse the varied rotational speed of an angled single u-joint, a second u-joint is used with an equal and opposite angle. The yokes of the two u-joints must be aligned (or phased) when mounted to the intermediate shaft. The second u-joint reverses the effects of the first giving a smooth rotational speed output from the second u-joint. At high speed, like with a drive shaft, even a small difference in angles will result in a pulsing of speed differences to the rear-end, causing a driveline vibration. Most lowered 510’s have a driveline vibration from highly angled half shaft axles and negative camber at the wheels causing a mismatch in u-joint angles.
Now in a steering system, the same rotational speed-up/slow down occurs. Because the speed of rotation is so slow there is no vibration problem, but the speed-up/slow down is transmitted to the steering rack and to the wheels causing them to vary in turning angle in relation to steering wheel input. The results are as you turn the steering wheel you will not get equal amounts of turning action at the front wheels.
In my case it wasn’t so much the speed-up/slow down caused issues as much as it was where the variance in speed fell in the steering wheel turning cycle. I’d turn the steering wheel one quarter turn for a right-hander and to match the same radius left-hander it took half a turn. Trust me it was not comfortable to drive, especially in a set of quick esses when the car started sliding and you had to counter steer!
I used a double u-joint from Borgeson to help correct the situation and later relocated the steering column so the bend at the u-joint was greatly reduced.
