Does a buyer have more leverage buying a used car when paying all cash versus securing a loan from the dealer/owner

Yes AND no. The dealership makes money on the finance of a vehicle when done through there finance department. Sometimes they make more money on the financing then on the vehicle itself. If the salesman asks tell them you have good credit. Try to leave it at that.

i did negotiate when i bought my daughter's first card, after i saw the car i told the salesman i had $5,500 CASH TOTAL TTL PLUS FEES, HE SAID NO, I SAID THANK YOU AND WALKED OUT THE DOOR, NEXT DAY HE CALLED ME AND OFFERED TO BRING ME THE CAR I WAS APPROX. 100 MILES AWAY, I TOLD HIM NO THAT I WOULD COME IN THE FOLLOWING WEEKEND,GOT THE MUSTANG CONVERTIBLE FOR $5,500 TOTAL - LESSON LEARNED HERE DO NOT LET THEM KNOW HOW MUCH YOU WANT THAT PARTICULAR CAR