You live in Mexico. They don't sell or service the car you own. You need a special tool.
What do you do?
1) Jump in the car and drive to Arizona. With tolls, fuel, food and the $10 tool you need, you spend about $150 for the tool.
2) Make your own.
I needed to remove the pistons from the motor of the VW Westy so I could replace them. However, there's a steel pin that connects the piston to the rest of the motor, called a wristpin. (If the piston were a hand, then the connecting rod is the arm and this pin is the wrist.) These are supposed to just slide in and out with a little resistance, but is everything were as it was supposed to be with this motor, I wouldn't be taking it apart. A wristpin removal tool is required.
This is the piston (already pulled out so you can see it). The wristpin is the inner circular object you see. The circlip has the two little holes at the ends. It acts like a spring to hold the pin in place.
I managed to find a threaded bolt long enough to go through the pin. Then I found a nut that screws on the end.. large enough it won't go through the wristpin, small enough to get around the circlip. Then I had to have a way to pull on that bolt with enough enough force to remove it.
This is the setup in the engine, the circlip removed.
I took a woodworking clamp and notched it for the bolt.
Then, the clamp fits on the motor like this and the clamp is tightened.
The force on the bolt pulls the wristpin out, and the piston is free to be removed.