Home Forums General Discussion Technical Questions Schindler 321A intermittent vibration issue

Have a schindler 321A 3 stop 2 stage single jack with a odd intermittent vibration issue. If the car sits for a while and starts to run in the up direction it starts to vibrate from what sounds like the bottom front of the car really bad until it goes into high speed but then starts to vibrate real bad again when it goes into the up slow down. After one run the vibration goes away and is only present in the up direction and never in the down until the car sits again for sometimes only 10 mins.

So far we changed the jack seals, added cat oil, checked the jack sink cables, verified the proper psi in the air muffler and made sure rails were lubed and not tight. We can't always catch the elevator doing it as it is in a busy building and will not always sit idle. The car currently homes to the bottom floor, so my next move to attempt to temporarily alleviate the fear of the elevator in the building is to move homing to the top floor to see if it makes a difference.

Does anyone have any suggestions??

Check all mounting bolts in tank that hold the pump and motor. Also check you have the correct coils on the valve.
I once had a valve cover vibrate off and fall into the tank and every now and again in the up direction the cover would stick to the pump strainer and cause a vibration.

You mentioned that you pressurized the muffler but was curious if the muffler is maintaining what you pressurized it to?Or is it leaking out into the oil?Also when you added the air did you do this with no oil pressure on the line by either buffering the car or using the machine gate valve and then opening manual lowering to releive pressure.I have also seen that if the packing is wiping the piston to dry then you can get some vibrations as a result especially at leveling.I have used every cloth on the piston above and below floor level heights to help the piston trap oil to keep it lubricated and had good results.Not to drag on but,be sure that the discharge hose in the tank is not near the intake of the pump,this can cause some issues with oil getting aerated and behaving similar to what you have.Sorry for the short novel,hope this helps.

Thanks for the replies. I think I will pump out the tank next to check out the idea of something getting caught in the pump. I didn't actually add any air to the muffler, I just checked it to make sure it was holding the proper pressure. No one has added any air to it any time recently so it appears to be ok.

Well we got to the bottom of it today. I couldn't see this with the oil in the tank but for some reason schindler used a long hose on the discharge side of the valve that went all the way down into the tank and stopped just above the pump, but at some point came loose and was getting sucked up against the pump screen causing the pump to cavitate. The only odd thing was why it would do it intermittently, but we re adjusted the hose and refastened it and we couldn't get it to repeat so I think it's solved.