Nissan Repair: ABS problem in 1991 300ZX TT, 300zx tt, wheels and tires

Question
Hi,
I recently replaced the struts/springs along with new brake pads and SS brake lines on my 1991 TT. I also changed to new wheels and tires at the same time; 255/35/18 on the front and 265/35/18 on the rear. Everything works fine except...
The ABS motors often now at very low speeds, especially if I'm turning left or right. The ABS will also occasionally actuate if I'm braking at the same time. The ABS light is not illuminated during any of this and shows no error codes, which makes me think the ABS system is working fine and there are no faults. I've bled the system 3 times per the FSM thinking I had air in it somewhere but I have excellent pedal feel, so I don't think it's that.
Could it be that the slight difference in tire size between the front and the rear is confusing the ABS at slow speed? I've got the ABS disconnected now and the brakes work fine.
The car only has 40,000 miles and is in otherwise excellent mechanical condition. Any ideas would be greatly appreciated.


Answer
Steve,

I would bleed the brakes with Ford High Performance Brake Fluid first.  If this does not resolve the problem then the ABS unit is probably defective.  No codes and the ABS going nuts is either the fluid, trapped air or a defective ABS computer.