Hello everyone

I have read several threads to find a solution to my hydrohoist leak puzzle but to noavail... I have replaced all air parts, including valves hoses but then realized that the leaks were coming from the fiberglass itself. I removed the tanks from lift and are sitting in my shop after giving them a good cleaning. I plan on using the air compressor to pressurize the tanks but not sure what to do the outflow hole at the bottom. Does anyone know of a good way to plug the hole which can sustain the air pressure? I'm really looking for a working solution that someone has tried before. Your help is appreciated. thanks.

what size hole?
if it's round these come in many sizes http://www.simplyplumbing.com/32047-...UnkaAmut8P8HAQ

I know on my 8K lift you can easily stick your fist up thru them with plenty of room to spare. .

If they are that big maybe let the air out of a small smooth fender or ball, stick it in the hole and air it back up

I made up some tapered nylon plugs years ago , they were around 4 " on a 6500 # 3 tube hydro hoist , still have one in the garage somewhere. They are drilled so you run big zip ties thru and cinch them up around the tube . A ball or small football and a hand pump would work better to seal but I wouldn't be putting much pressure to those tanks

Hydrohoist makes a tank plug you may be able to adapt something on your own .
Keep in mind the tanks Max out at 5 psi in air so carfull when testing them

What is the age on the tanks?

I would plug top hole with threaded fitting role it over and fill it with water safer then air. To much air could blow out the tube

This sound like the best way

The expansion plugs shown will work. Just get the right size