What are these screws for?

[AngryBird]

Broken Floor Jack... I've read the sticky.

Hey Everybody. I'm having trouble with a craftsman hydraulic jack I bought a few years back. It won't lift or hold loads. I added hydraulic jack oil and have bled and bled and bled it per the manufacturer instructions. I keep getting air out while bleeding like some is leaking in somewhere. Before I really start tearing into it tonight, I want to make sure the problem is not something simple. Can anybody tell me what the 4 screws/plugs are in the picture below? The only one I'm sure of is the uppermost. That had the do not adjust cap on it so it must be the high pressure bypass. This is a "fast up" jack too which I think is confusing things even more for me.

Thanks in advance.

AB

 

[scw1991]

I was going through some manuals I found online (Sears jack - no particular model) and under one screw (nearest the plunger) there is a suction/delivery ball valve assembly. Under the other screw (assuming far right side), there is a safety overload valve assembly with needle valve and spring. Release Valve (perhaps under phillips head screw) lowers the saddle.

Sounds like you have a small air leak within the plunger assembly which is not allowing it to prime drawing fluid from the tank reservoir into the cylinder.