"Bouncy" platform on Upright Tiger after hose replacement?

[Radius]

So this is kind of messing with my head a bit..

I have an old Upright Tiger scissor lift. I blew a hydraulic hose to one of the lift cylinders yesterday. So I lifted the platform with my forklift so I could access the hose fitting at the cylinder and had a new hose made. I put the new hose on, refilled the hydraulic tank with the specified ATF and let the platform back down.

Now I have a couple of new problems. When I use the toggle switch to lift the platform, it takes 5-10 seconds for the pump to generate enough pressure to lift the platform. The other problem is that now when coming down from an elevated position, the platform bounces on the way down. The lift uses dual stage lift cylinders and the bouncing problem only occurs on the first (primary?) stage. It does not bounce on the secondary stage.

At first I thought that maybe I had air trapped in the cylinders, so I put an assistant (AKA The Pretty Wife) in the platform and lifted it with my forklift. Then I had her hold the down switch and let the platform back down with my forklift.

This didn't fix the problem.

Any ideas?

Thanks,
Michael

 

[Deeretracks]

You still have air in the cylinder for sure.

 

[Hardline]

Air, cycle all the way up and all the way down a number of times.

 

[Radius]

You still have air in the cylinder for sure.

Air, cycle all the way up and all the way down a number of times.

I've gone up and down probably 10 times with the same result. Any other ideas on how to bleed or just keep going up and down?

Is it possible I may have damaged something in the hydraulic system by lifting the platform manually with my forklift?

Thanks,
Michael

 

[Dave_D]

Should be an allen hex screw/plug at the top of the cylinder. You will need to crack it while it is up in the air to get the air out. May have to do it to all cylinders. Be careful. The lift will lower as you open the screw.

 

[Radius]

Should be an allen hex screw/plug at the top of the cylinder. You will need to crack it while it is up in the air to get the air out. May have to do it to all cylinders. Be careful. The lift will lower as you open the screw.

Excellent! Thank you for the information. I will look to see if my cylinders have that bleeder screw.

Michael