The front and rear tone rings look good.

I removed the ABS fuse and the vehicle no longer makes the "clunk" noise, the rear wheels appear to brake properly at same time, the fishtail no longer occurs.
This leads me to believe the problem is definitely with the ABS system (maybe the pump / control module?)

For the 2007 Escapes, are there independent hydraulic cylinders on each wheel, or is everything in the main ABS control module near the engine?

I'm going to bring the vehicle for an ABS diagnostic run, for real time stats on the sensors / system while driving.
The ABS control module/pump are somewhat pricey, dealership is quoting $750 for OEM part.

 

Since the ABS operates from info received from the wheel speed sensors the diagnosis should start with verification that the sensors are providing correct and reliable info to the control units. An intermittent signal from any one of them could be responsible and has to be verified. After that is completed and all info is good the remaining pricey parts are suspect and with the proper diagnostic tools ,most of the time, the faulty component can usually be located. It does take some time.

 

I know it is strange but you will not believe that there was same brake problem. i tried many solutions and searched on internet, asked my friends but it did not work. at last i visited to Greeott's Brake & Wheel . They are expert in brake repairing.They can answer all questions related to brake repair/service. Greeott's Brake & Wheel center offer a wide range of auto repair services including Tires change,breaks,shocks,alignment,suspension,ac service etc.