Stuck Up Scissor Lift

[Cruzan80]

Picked up a Snap On mid-rise scissor lift (either a EELR300A, or a 6000A) a bit ago, owner said it needed work. First discovered the motor/pump connection was missing, replaced coupler (explains why it wasn't working before).

Below is how I got to this point. Right now, the lift is 90+% up, and not coming down at all. Tried pressing the button/lever multiple times, even took out the lever assembly, and both check valves. Biggest culprit remaining is debris in the 90deg velocity valve at the bottom of the piston. How do I access this without either bringing the lift down on top of me, and/or making a mess releasing the rest of the hydraulic fluid when I loosen the fitting?

Beginning Steps:
Initially filled the tank with new oil, was tripping the breaker at the beginning (on an extension cord). Took off the hose, and ran it for a few seconds until I got fluid out of the pump. Then hooked up the hoses, and began to fill the lift. It slowly started up (no load for first test). When it was about 70% up, it ran out of fluid, and I added more to the tank. Got it almost all the way, 90+%, and the bottom side of the piston has a blast of air with a bit of oil spray. Is this just self-bleeding? Kind of sounded like if the safety release on a compressor opened. Waited a min, lifted a bit again, worked. There is a bit of oil dribbling out of that hole, guessing new seals (piston and gland) are in the future. Cheapest I saw was about 150? (00181 and 00183 are parts nos).

 

[metlmunchr]

Can't tell you how to get it down without making a mess. For me, a mess just always seems to be part of the job when working on hydraulics.

It could be stuck in the up position because a sliver of rubber has peeled off of the piston seal and jammed between the piston and cylinder bore. I've run into this a few times in repairing cylinders, and it's really surprising just how tight something like that can jam the piston.

Sorta difficult to understand what you're saying about a mix of air and oil blowing out of a cylinder port. A picture showing the cylinder and it's arrangement in the lift as well as the point where the air is coming out would be helpful.

Re the seals, if they can be identified by type and size, you can likely purchase them from a company like Hercules Hydraulics for a fourth of that $150. If you have a caliper to get some accurate measurements and the ability to post pics of the seals once they're removed, I'm sure several people here can assist you in identifying them.

 

[FMB4]

Did you bleed the hydraulic system as per the manual? Is the Safety Pedal disengaging properly?

http://www.snaponequipment.com/Common/productmanuals/LR/EELR300A/EELR300A.pdf

 

[Cruzan80]

So I guess mine is a 6000A, single cylinder. I don't have a safety foot pedal to bleed with. Manual says it is a self-bleeding system. I did raise a bit and stop, didn't lower initially. Was too excited that it started working.

https://www.snaponequipment.com/Common/productmanuals/LR/6000A/6000A.pdf

Will post pics of it in a bit. My question about a "mess" was more regarding how to try and collect any hydraulic fluid left in the cylinder, vs just letting it spill in the yard. And how to keep the upper portion from crashing onto me (thing weighs a ton).

 

[leadfoot415]

So I guess mine is a 6000A, single cylinder. I don't have a safety foot pedal to bleed with. Manual says it is a self-bleeding system. I did raise a bit and stop, didn't lower initially. Was too excited that it started working.

https://www.snaponequipment.com/Common/productmanuals/LR/6000A/6000A.pdf

Will post pics of it in a bit. My question about a "mess" was more regarding how to try and collect any hydraulic fluid left in the cylinder, vs just letting it spill in the yard. And how to keep the upper portion from crashing onto me (thing weighs a ton).

Just get some scrap 2x4/4x4's and build some cribbage to support it so you dont get crushed.

 

[Cruzan80]

That may work. Would be some tall cribbage. Was thinking of jack stands on cinder blocks to start.

 

[Cruzan80]

Right now it is about waist high in the picture. Took a photo of the lower joint (where I think the 90deg velocity restrictor is), the upper joint and the bleeder hole (just above the black crud).

Is there much fluid in the actual cylinder? My initial guess is to loosen the hose fitting at the bottom, raise the hose to allow the fluid in it to drain back into the pump, and then loosen the 90deg weather head. The upper 90 where it enters the pump is welded on. Would probably try to do this standing inside the lift, so it can collapse around me, instead of under it. But not sure how messy that would be.

 

[Bighead38]

Flip it over and work on it upside down.

Could also use cribbing and brace it. Don’t use cinder blocks.

 

[Cruzan80]

Unfortunately, short of a skidsteer, I am not flipping this. Way too heavy to lift. Planning on cribbing it up

 

[LXCam]

Not to be that guy without a clue. But since I don’t know if that lift has a mechanical safety and I don’t remember seeing it mentioned. Does it?

 

[Cruzan80]

Yes, it does. However, it is about an inch shy of engaging. Are you suggesting running it up to the safety, and then I can remove the entire piston assembly? The only issue I see with that is that it is a "raise past, then lower down onto" kind of safety, and I don't have a controlled way of lowering (besides possibly loosening the weather head fitting slowly). If you look at the pic with the cylinder, it is the part to the right (grease zerk). Flips down, and then has a V cutout that engages the right side shelf off the piston.

Edit: Can't pull the piston since it is holding the safety, but should be able to pull the 90deg velocity and check for debris this way.

 

[LXCam]

Ya I’d run it up past the safety and then start the operation. If you don’t feel comfortable running the pump anymore you could always use a jack to finish the lift then it might settle back into place on the safety without having to bleed the cylinder.

 

[Cruzan80]

New Update: I think something in the Piston is causing the issue.

I tried to first run the pump up to see if I could lift the piston/safety enough to engage. No luck. Pressure built in the hose to the point where it was dumping back into the tank at the bottom, without lifting any more. There was a bit of seepage from the bleeder point as well. Then I tried putting a jack under the cross-member where the top of the piston is. Jacked it up, and when it started to engage, was lifting the bottom of the lift off the ground, rather than having the piston raise any further. So no luck raising the piston enough. I then very carefully started to detach the hydraulic hose from the piston (a bit of fluid ran out, but not too much), and then even more carefully unthreaded the 90deg weatherhead. I got it to the point where it was loose, and then was flicking it with my finger from overhead until it unthreaded. It is now off, and the lift is still stuck in the air.

To sum it up, on pg 11, the #10 assembly is now off (https://www.snaponequipment.com/Common/productmanuals/LR/6000A/6000A.pdf). There is no fluid coming out that I can see (maybe really slow?). At this point, I am now really not sure what to do. Support the arms the best I can, remove the snap rings from each side of the 4th photo above (#15 on pg9), and then have the lift fall when the piston is no longer connected to the arms (drive #14 on pg 9 out)? Worried about the amount of weight freefalling in that case. Or do I try and pull the bushings and cotter pins that connect the black part to the red part (#22 and 28 on pg 9), so I can reduce the amount of weight on top?

 

[Firebrick43]

Take a 2x4 and cut to the distance between the top and bottom frame. Get another two 4 or so inches longer and bolt them on both sides of the first one. Now the support can not come out, pull the pins of the cylinder and take it to a hydraulic shop.

Now the question is why. Did this set outside for some time???? I guess water could have made its way into the cylinder and rusted the inside of the cylinder but its extremely rare for hydraulic like your talking. A single way cylinder such as you have would puke oil out the vent hole (little hole in picture 3 if the seals were bad) unless some one has placed a set screw or something in this hole the cylinder should not stop short of a bent rod. Even bent rods will continue to function just fine many times.

If that vent port is blocked however and oil gets past the seals it will hydro lock.

 

[Cruzan80]

Thanks, a support like that was what I was thinking. Possibly 2 sets, one a bit shorter, and keep stairstepping it down, so I don't have to leave it up. It was stored outside for a bit once I got it, not sure how long it was outside before. When it bled air, I saw air/oil and possibly dirt coming out vent hole. When trying to raise it up the last bit, oil dribbled out the vent hole. Worth trying to stick a pick up in there to dislodge any debris?

I feel fairly confident in being able to fix the piston/ram once it is off and I can open it up, just trying to figure out how to lower the lift safely for now. Have a 7yo and two dogs, so don't just want to leave it up on cribbing.

 

[Firebrick43]

know anyone with a handiman jack???? aka farmer killers? After cribbing and getting the cylinder out they could lower it, just be care and don't let yourself get in the line of fire.

A pick may break something up. It seems to me that this upper chamber is hydro locked possibly. Water may have ingressed and rusted the interior of the cylinder. it is on the side up when the lift is lowered. Don't store it outside anymore.

 

[Cruzan80]

Agreed, it will be stored indoors once it is operational. I have had it outside for max a 2-3weeka, not sure how long PO had it out. When I stuck a pick in, and wiggled, it went further in when pointed up at 45deg (towards top of cylinder). Much darker fluid came out, but not a lot and stopped when pick removed. Next idea is an engine hoist or gantry crane from the top to grab it.

Cylinder will not being going back on until it is back inside. I can't really see any issues with the frame being outside for a bit?

 

[ItsNemo]

Are you sure you don't just need more weight to get it to go down? My Bendpak scissor lift at full rise without a car will barely move unless I get a couple hundred pounds on each platform.

 

[Cruzan80]

Not sure how I would get more weight onto it. I have stood on it and "bounced", without any movement.

 

[Jagmandave]

An engine hoist sounds like a pretty good way to hold it while you remove the cylinder, then let it down slowly......

 

[Firebrick43]

engine hoist on the end rail is a bad idea, pull the pin of the cylinder and the bottom rail will come up to meet the top one. It will still collapse just in an unpredictable manner. You have to have some way of positively separating both rails

 

[Cruzan80]

Why would the bottom come up? Everything is hinged in the center, was going to support the crossmember at the same area as the piston currently is. Then slowly lower the upper part of the scissor down. Not going to grab the black part.

 

[Firebrick43]

Why would the bottom come up? Everything is hinged in the center, was going to support the crossmember at the same area as the piston currently is. Then slowly lower the upper part of the scissor down. Not going to grab the black part.

They just are not hinged in the center, see the rollers on the far end bottom, and there is some at the top as well.

If you hold it up by the top crossmember on the cylinder end, when you remove the cylinder pin it will far side will fall and the scissor arms will fold and the bottom cylinder side will come up.

I have worked on a lot of industrial scissor material lifts in the 4000-12000 lbs range and they will crush you in a heart beat if you do silly things. They all come with maintenance blocks to lock the rollers on the bottom but they have a frame to react them against.

If the top rollers on the end opposite of the cylinder are captive in tracks you could lift on the center crossmember but i don't know the weight and or capacity of the lift and engine hoist.

 

[Cruzan80]

They just are not hinged in the center, see the rollers on the far end bottom, and there is some at the top as well.

Yes, there are bottom rollers on one half, and the other half (with a crossmember ton the ground) has small wheels up top.

If you hold it up by the top crossmember on the cylinder end, when you remove the cylinder pin it will far side will fall and the scissor arms will fold and the bottom cylinder side will come up.

Why would the far side fall? This is where I am missing the point, I guess. The bottom of this half has a crossmember where the piston attaches. Are you saying the black part on top has enough weight to overbalance the bottom crossbar? I would think adding weight to the bottom would help counteract if I needed to. Or simply put a brace under the end opposite the lifting side.

I have worked on a lot of industrial scissor material lifts in the 4000-12000 lbs range and they will crush you in a heart beat if you do silly things. They all come with maintenance blocks to lock the rollers on the bottom but they have a frame to react them against.

I appreciate your advice, and not trying to fight at all. Just understand what you are saying.

If the top rollers on the end opposite of the cylinder are captive in tracks you could lift on the center crossmember but i don't know the weight and or capacity of the lift and engine hoist.

The gantry crane is a 3ton, easily up for the task of supporting it.

I will be working on it from above, inside the black area. So even if it folds on me, I will make sure there is nothing in the pinch zone. I may even try and set some 2x4s in between the scissor areas, just to ensure there is some slack if it does fold.

 

[Firebrick43]

Yes, there are bottom rollers on one half, and the other half (with a crossmember ton the ground) has small wheels up top.

Why would the far side fall? This is where I am missing the point, I guess. The bottom of this half has a crossmember where the piston attaches. Are you saying the black part on top has enough weight to overbalance the bottom crossbar?

Yes, gravity pulls the one end down(because the other is held up by the hoist. This downward motion on one end forces the other up due to the scissor mechanism that with out the cylinder is unrestrained and will come up.

I would think adding weight to the bottom would help counteract if I needed to. Or simply put a brace under the end opposite the lifting side.

Yes, Both of these methods would counter act gravity.

I appreciate your advice, and not trying to fight at all. Just understand what you are saying.

The gantry crane is a 3ton, easily up for the task of supporting it.

Three ton is usually fully retracted but there is the issue of the wheels on the hoist. almost all engine hoist need the wheels under and in front of the load unless its a counterweighted hoist which are pretty uncommon.

I will be working on it from above, inside the black area. So even if it folds on me, I will make sure there is nothing in the pinch zone. I may even try and set some 2x4s in between the scissor areas, just to ensure there is some slack if it does fold.

If you are pulling the cross pin on the cylinder, you are in the pinch area

 

[LXCam]

So you’re saying it’ll do a wheelie???


Neat’O

 

[Cruzan80]

3ton Gantry crane, so it will be able to straddle the area easily. No worries about where the wheels are, and lifting straight up.

The pin on the cylinder is inside the arm that is not going to move, and the arm we are worried about is outside those. So if I reach in to pull the pin from over the top (gap in the black area on top) making sure I am standing outside where both arms lay, I think I should be ok. Planning on tapping out the pin with a hammer to keep my hands out of the way as much as possible. The only pinch areas are between each of the red legs, and between the black and the red area, correct? Again, I am planning on putting some kind of brace between each of the pinch areas, as well as bracing the top of the alternate leg to make sure. One of those where the more safeties I can put in place, the better.

Edit: Talked to my buddy with the gantry crane, and will be dealing with this next weekend. So if it somehow magically lets off the pressure between now and next weekend, problem solved. If not, please keep offering suggestions.

 

[Cruzan80]

So we finally got a chance to work on this. Some progress was made, all of it safely.

First, when strapping it down, we got it to lower some just using a ratchet strap over the top (this was unintentional). The safety caught the inner lip to hold it securely. Got over to my buddies without issue, and we ended up using one of the forks on his forklift to support the upper arm.

Snap rings came off without issue for the top pin, the bottom cotter pins were pretty well rusted on there. So I used a pair of pliers and snapped off the ends. Took a long length of rod, and started to try and drive the upper pin thru.

This is where it got interesting. Even though the bottom leg was strapped down, it apparently wasn't tight enough, as it raised off the ground once we got the pin thru the piston. HUGE SHOUTOUT TO FIREBRICK FOR MAKING ME AWARE OF THIS POTENTIAL!!!

Because I was using a length of rod, there was nothing in the pinch zone once it popped loose. I "think" I would have been ok without knowing this could happen, but better to be doubly safe.

We were able to lower it down safely, using the forklift. Currently, the lower pin holding the bottom of the piston is frozen, to the point where the piston will not even rotate easily. Tried to move it with a prybars, and a mallet to no avail. Sprayed with penetrating oil, and going to do that again tomorrow, with some heat, and a bottle jack for pressure.

Then I will be able to remove the inner snap ring to access the guts of the piston, and see what happened. This has definitely lived outside, as there is quite a bit of gunk on the upper pin. Once I get the piston off, I will make sure all of these parts are clean before reassembly.

 

[Chemist]

I actually will be taking delivery of the exact same Scissor lift from a car dealer, and I am told that it all works properly. It is going to be delivered to my house on Thursday night, and I am really hoping it all works properly as I am told by the seller. I am on other boards, and I know the people that have them really like using them. I guess I will find out soon enough