Benwill lift hydraulic issue

[pontiacjeff]

I purchased a used 9k Benwill lift. cleaded it up and installed and wired recently. I bled the system and lift moves up and down wo weight on it. Yesterday i decided to do trial by fire and put my f250 diesel extra cab on it. Approx 7800#s. The lift will start to elevate the body and extend the springs but wheels never came off the ground.
What are the most likely suspects? piston seals? low pump pressure/rebuild pump? air in system still? Thanks in advance

 

[pattenp]

If piston/ram seals were bad you'd see fluid leaking out. Most likely air in system or worn out pump.

 

[Bondo]

Ayuh,..... If the motor is runnin', but the lift not liftin',.....

I'd plumb a gauge to the Up-side to see what the pressure is to the cylinders,.....

 

[pontiacjeff]

motor definately working, i had removed motor from pump at assembly and everything looked good. I figured it wouldnt work at all if the plastic spur was shot i have a guage that was the direction i was headed too.

 

[86turbodsl]

Pics or it didn't happen...

 

[firebirdparts]

You'll want a gauge that goes to about 2500 psi, or some such.

 

[pontiacjeff]

ok guage check is good, it buries a 3000 psi guage as soon as you hit the button. Further review looks like the far side cylinder is not following the near side. Has hydraulic oil right to the bleeder. At this point I am ordering a rebuild kit for the cylinder and assume it is blowing by the packing.

 

[pontiacjeff]

took cylinder out yesterday after ordering rebuild kit. Rod is fine, orings and packing roached but worse is the inner bore of the cylinder. It is pitted, must have been stored with water in it. I am going to try and hone it so the seal will not get ruined, anyone aware of replacement or rebuld cylinders for a bpoa-9? I am going to cal SVI monday, but i am expecting a crazy price tag. My brother mentioned a repair facility in NH that may be able to fix the cylinder.