When it comes to Automotive Maintenance among many other things, the humidity in Japan proves to be a powerful force of destruction.
Water build up in this hydraulic system caused the hoses to rot from the inside out and ultimately fail. The reservoir was also internally rusted.
The original system used brake fluid to power the hydraulics. This type of mechanism should be flushed regularly with fresh fluid to insure you get the longest life possible, especially around humid environments such as Japan. The new pump was re-installed and lines were carefully routed.
You can tell the fluid is in desperate need of change if the fluid color is milky. Fresh fluid should be clear.
Later systems use Automatic Transmission Fluid or Hydraulic Fluid. The system I used to replace the faulty kit required Dexron 3 fluid.
It is critical to insure that the hoses are routed in a manner that the top mechanism and cylinders do not come into contact.
After all is checked for clearance and the system is air-bleed, the top should be adjusted for window clearance. There is a 5/16 square head bold used to adjust the top sag.
I ran the top up and down a couple times then let it sit for awhile to let the air bubbles escape. Then ran it thru a couple more cycles. Working great!!