Originally Posted by Caps18
I am borrowing an engine hoist that rarely gets used (hasn't been used in the last 8 years...), but it seems that it is having problems holding. The arm slowly drops back down after you work really hard to pump it up. Well pumping it seems too easy compared to other jacks I have used.
I have tried to bleed the air out a few ways, and I have filled up the cylinder with hydraulic oil. I am not sure if I have been successful at getting all of the air out. I'm not sure if there is a bubble in the small pump piston from when it got turned upside down. I've tried opening up the release valve and pumping it like the manual says to get the air out.
Is there something else I should try to get this to work?
If the arm slowly drops then you may have a blown seal somewhere in addition to trapped air. But first, it can take quite a bit of effort to get the trapped air out. You might try tapping the cylinder (with a large screwdriver or a hammer handle) as you pump, in order to encourage the air to migrate.
Most engine hoists have a large mechanical advantage and it will take pretty much no effort to pump up the beam by itself. When I'm raising my hoist to take up chain slack I usually don't even put the lever handle on, I just wobble the end on the pump directly by hand. It's faster and it keeps me from smashing the handle into something