Bendpak 4 post lift issue, surging going up, and down.

[Gunner75]

Bendpak 4 post lift issue, surging going up.

Have been using my Bendpak 14T quite a bit and started running into a few little issues.

I've got a ticket in with Bendpak but thought I'd see if any of you had similar issues. Waiting on call back.

My main issue is while raising the lift, it get's a few feet off the ground and the lift starts surging. Not loosing power to the hydraulic unit, motor doesn't slow, but lift starts shaking/surging/pulsating.

I use ATF as a fluid in the 220v unit.

When lowering I was getting some creeping noise, etc so I lubed up the phenolic lift blocks with Mystic JT-6 Aerosol Grease. I had previously lubricated with white lithium but had one or two posts that dried up a little.
This made zero difference on going up, but quieted the unit down when lowering it.
While lowering, no surging is present.

I raised and lowered the lift probably 30 times over the last two weekends ensuring lube was where it needed to be and while I was working on it.

It almost acts as if the unit is building too much psi and it regulates itself or similar.

Thoughts?

 

[66Caprice]

Is the fluid full when the lift is fully down? When I first got mine it started doing that a couple days after set up. It was low on fluid.

 

[Gunner75]

Yes it is, sorry should have included that. I initially filled it per instructions. I put 1/2 to 3/4 of a quart in a month or so ago before I knew I was going to start using it more.

 

[LX-Markham]

Re: Bendpak 4 post lift issue, surging going up.

When lowering I was getting some creeping noise, etc so I lubed up the phenolic lift blocks with Mystic JT-6 Aerosol Grease.

Thoughts?

I did similar, and I found that the grease would actually make it worse, almost binding, similar to the "surging" you are describing. The guides and rails work much better when bone dry and clean.

 

[larry_g]

Is there a filter on the inlet of the pump between it an the reservoir? I had a similar problem with a trailer lift and it turned out to be a clogged filter that was buried in the reservoir.

lg
no neat sig line

 

[Gunner75]

larry_g, I believe it does. I don't have the manual with me and no manual is offered online. It is pretty good rhythm and is very consistent. Doesn't appear to take much to remove the tank. I'll put the lift up and see what I find this evening. Would be pretty great if that is the issue.

Still have yet to hear from Bendpak. I'll buzz them again today. They have always been pretty responsive.

 

[erik a]

I had some "surging" issues while lowering.
Found out one of my columns had gotten out of plumb.

Erik A

 

[Gunner75]

No contact with Bendpak yet. Pulled the reservoir off last night (while the lift was in the upright position), lift on locks. 2 or 3 quarts remained in the reservoir. It has a nice filter on it, not plugged at all. Little bit of trash in the bottom of the reservoir, but nothing to restrict or worry about. Went ahead and cleaned it out and filtered that fluid.

Went ahead and reassembled after snapping a few pictures. Thought maybe I could find a diagram of that type of pump, psi relief, etc.

I thinking at this point the psi relief valve is dumping then closing causing my issue. Not sure if this valve is adjustable, has a bit of trash in it, etc so I opted to do some research.
Haven't found any diagrams on that pump yet, will look more today.

Pump number is CBK-2.1F
21MP
201807020

 

[Gunner75]

Have a new Hydraulic Power Unit and Cylinder coming my way. I'll get this properly updated upon repairing the lift.
Cylinder replacement is due to leak. More on that later.
Power Unit has an internal issue. Will update on this to what is exactly wrong with it soon.

 

[Gunner75]

Sorry for the late update. Lift is fixed. Early last week I swapped out the cylinder (due to leak), and the Hydraulic Power Unit.
Definitely a Power Unit issue.
I had already intended to go with ISO 32 or 46 fluid however when this unit arrived it had a label on it that said to "Use ISO 46 Only".
Now that everything is running smooth, I look back and wish I would have done a fluid flush and went with an ISO 46 as my hydraulic friends suggested.

All of the lifts I ran when I ran auto shops and or was a tech had ATF in them. It wasn't until I had this issue that a few came out and reported they switched to 32 or 46 Hydraulic fluid.


I need to mention that cylinder I had always had a drip on it, however it never hit the floor. Upon trying to adjust some items mentioned by Bendpak this drip got excessive and would leak a small puddle on the floor overnight. (6 to 8") AKA, always pull the cable boss back to access the flats of the shaft when adjusting the cylinder nut. Never trust thick leather and a cylinder clamp. Lesson learned.

 

[PoorOwner]

Sorry for the late update. Lift is fixed. Early last week I swapped out the cylinder (due to leak), and the Hydraulic Power Unit.
Definitely a Power Unit issue.
I had already intended to go with ISO 32 or 46 fluid however when this unit arrived it had a label on it that said to "Use ISO 46 Only".
Now that everything is running smooth, I look back and wish I would have done a fluid flush and went with an ISO 46 as my hydraulic friends suggested.

All of the lifts I ran when I ran auto shops and or was a tech had ATF in them. It wasn't until I had this issue that a few came out and reported they switched to 32 or 46 Hydraulic fluid.


I need to mention that cylinder I had always had a drip on it, however it never hit the floor. Upon trying to adjust some items mentioned by Bendpak this drip got excessive and would leak a small puddle on the floor overnight. (6 to 8") AKA, always pull the cable boss back to access the flats of the shaft when adjusting the cylinder nut. Never trust thick leather and a cylinder clamp. Lesson learned.

I don't think the iso32 vs 46 is going to make that much a difference at least not to the extends of solving your issues.
I have seen some power units specify iso 46 because probably it is generally hotter in Asia. But the lift manufacturer will say put iso32 in it.
ATF has a viscosity similar to 10W and ISO32.

 

[Gunner75]

I wouldn't think 32 would do anything, maybe 46. This lift didn't act up until it got hot. PSI valve or Relief valve issue I'm guessing. Pretty sure I would have seen a difference going to 46 from ATF but that's just me. I was going to chill the ATF in the fridge in my shop, dump in, and run lift. Almost certain I'd have seen a difference.

Ok, if I'm off on the above, what would cause the major surging on rise? After repairs, rise is smooth, and decent is even smoother than ever.

In the end, I guess I don't really care, but if a simple fluid change/flush would have made a difference then maybe I would have spent the $ to give it a go. My Hydraulic guys get away from ATF any chance they can as they reported. "Not transmissions", sticks valves in lifts, jacks, forklifts, etc. Flush and run."

I've never seen a surge in a power hydraulic pump like this ever. Like it was over psi, and or regulated was dumping and not recuperating soon enough. Cable pause was 1" then travel, 1" then travel, etc.