It's a 1999 Astro RWD Hi-Top Mark 3 with 210k Miles.Year?
Can I ask you, what did it feel like? Right now I feel like my steering wheel and brakes have LIFE. Because when I move my steering wheel it pumps the brakes without me touching the brakes. Feels alive. Did your van feel unstable too?Sounds like the VERY COMMON AWD turning lockup issue
My 2000 AWD did that too
Brake pedal does sink to the floor slowly, and when I turn my steering wheel the brakes go up and down. I think the van being unstable is more what I feel in my head, because I'm not used to driving like this. It just feels off. I drove on highways this morning perfectly fine, but in the back of my head there is still something that makes me think my van didn't operate the way it normally does. ABS lockup may cause this uneven ride? if I press the brakes the van starts limping (very small can't even tell) and it's just such a weird feeling!I have never ever seen nor heard of a faulty ABS pump causing steering problems.
Certainly not binding the drive train. Not possible.
Seems more than likely you are having an issue with the power steering/hydroboost system.
If the brake pedal goes to the floor and steering is difficult, that points you in that direction first.
Mechanic seems to be replacing itens at will without knowing what the actual problem is.
All of those are testable, sounds like you need to find a new 'mechanic'.Repair Background:
Last week it visited the mechanic 5+ times because of a stalling issue. This was done In order starting from fuel pump. It kept on stalling until the crankshaft position sensor was replaced and now it's good. Mechanic changed:
1) Fuel Pump
2) Ignition Module and Ignition Coil
3) Distributor and Cap
4) Crankshaft Position Sensor