86 Convertible Hydraulics

[mikes in australia]

I have used a Full Synthetic ATF Auto Trans Fliud in the Hydraulics for the Convertible top and all has seemed almost fine until recently.
The pump is working, but with no pressure to operate the top.
Have checked and found small leaks, but would not consider bad enough to cause the top not to lift. Tightened the hose connectors to the cylinders and removed the pin connecting the cylinders to the top. There is not a lot of pressure required to push or pull the rods. Operated the pump and the cylinders worked, although I can hang onto the rod and stop the rod from going in or out.
The pump has the correct amount of fluid, and with the filler plug out, operated the pump and did not hear any signs of air in the lines.
The cylinders are near to new and I can feel fluid on the rod, but could not see any collected in the top of the cylinder that would indicate a leak, only through the hose connectors which I have now tightened.
As the pump motor seems fine, is a seal kit for the pump the next step, or is it the Synthetic Fluid or are the cylinders stuffed?
(As I was using the Synthetic Fluid in the AOD and Power Steer, thought it would also be ok in the hydraulics for the top, then one fluid did all.)

[mikes in australia]

Update,

From Convertible Service [sales@convertibleparts.com]

The hydraulic system in the 1986 Mustang and all Fords since 1966 use Dexron III, or an equivalent. NEVER use ANY type of synthetic fluid because it will likely damage the pump rotors and make the motor useless.

[emerygt350]

ouch, not good... now I know not to try that...

[TheWizard]

I used Royal Purple synthetics in my 86 vert for years, never an issue.

[Neener]

Related question; anyone run the convertibles as manual and remove the hydraulic systems all together? How much weight was saved in doing so?