2 Post lift repair question.

[samert111]

One of the cylinders on my Forward DP97 two post lift is leaking at the lower gland seal where the rod exits the cylinder. It's the cylinder opposite the pump and controls. I have the seal kit for the cylinder and want to remove it to rebuild it.
If I raise both carriages normally to the top so the rod is up inside the cylinder, then remove the 2 nuts where the rod connects to the carriage, can I just lower both carriages normally to clear the carriage from the disconnected cylinder, while relying on the equalizing cables to support the weight of the disconnected carriage until I can apply the carriage stops to relieve the hydraulic pressure so I can disconnect the hydraulic lines and remove the cylinder?

 

[OccupantRJ]

Can you raise the lift, then lower it onto the stops to be able to remove the cylinder once the cylinder is unloaded? You will need lots of shop rags when you tackle it as hydraulic work tends to be rather messy. If you have the tall support stands used with lifts I would also tend to use those for backup support of the carriage. I would also watch a video on the process for ideas, and be aware that some hydraulic cylinder assemblies can have tricky retainers in not so obvious places.

 

[samert111]

Can you raise the lift, then lower it onto the stops to be able to remove the cylinder once the cylinder is unloaded? You will need lots of shop rags when you tackle it as hydraulic work tends to be rather messy. If you have the tall support stands used with lifts I would also tend to use those for backup support of the carriage. I would also watch a video on the process for ideas, and be aware that some hydraulic cylinder assemblies can have tricky retainers in not so obvious places.

On this lift the cylinders pull the carriages up, so I need to raise it all the way up to compress the cylinder and remove the 2 nuts that connect it to the bottom of the carriage. At this point the cylinder is inside the carriage, and it needs to be lowered to clear the bottom of the cylinder so I can swing it out of the post.
I did watch a you tube video on the same lift where they used an engine hoist to lower the disconnected carriage down while using the pump controls to lower the other side at the same time. I understood that part, but they didn't show how they lifted it back up to connect the carriage to the new cylinder. The other carriage needs to go back up at the same time and the only way to do that is with the pump motor and to do that the hydraulic lines would need to be connected to both cylinders, then the new one will start to extend. They left out alot of the details.

 

[FTG-05]

I'm resealing my 2 post lift cylinders as we speak. Atlas/Direct Lift with single acting cylinders; they extend to lift. They are only held by the bottom plate for the rod end and holes in the carriages for the cylinders (plus the hydraulic fittings). I got mine up just before it ran out of oil, it was leaking so bad. I left it locked up high as that's the only way to remove and reinstall the cylinders. You just have to watch your head!

Carriages high, cylinder #1 lowered, getting ready to remove it. I had to get my BIL's help to do #1; I did #2 by myself. You can see how much it leaked when the seal on #1 failed catastrophically.

You can see the mount at the bottom of the cylinder that lifts the #1 side carriage.



Good luck!

 

[samert111]

Circling back on this thread.
Today I pulled the end cap and replaced the seals with the kit I got from Carliftparts.com
As I suspected, once I disconnected the cylinder shaft from the carriage, the equalizing cables supported the carriage weight and as I lowered the other carriage using the pump controls the disconnected carriage came down with it to allow me to swing the end of the cylinder out of the column and remove the end cap. Then I used the pump controls to raise everything back up and reconnected the repaired cylinder.
Hardest part was rotating the retaining wire out of the end cap slot to allow it to come out of the cylinder barrel.
To protect the new seals during reassembly I used a pc of 3/4" shrink wrap over the shaft threads, but I think a few wraps of electrical tape over threads and some grease over the tape would work just fine.