1969 Dodge Dart GT Convertible Stock Resto

The tear down process has begun. We started taking apart the trim, front fenders, lights, bumpers, ect...

The convertible top stopped working this summer so I wanted to do some troubleshooting before the whole car was apart. I could see the pump was very low on fluid. The motor was running but I could see large amount of air in the lines. The cylinder on the passenger side is leaking (pictured). So does anybody know the easiest way to fill the system with fluid?

I believe we will be replacing both the cylinders and the lines but keep the pump. A whole new setup through Year One is expensive. Any suggestions?

Also so far there is less rust than I thought there would be, the front fenders look solid, just some rot on the top ridge of the inner fenders, seems common for the Dart.