The Stovebolt Site Forums The Parking Lot Big Bolts 1946-47 Scissor Hoist questions?

OK, I thought I understood dump beds, but I do not I guess. All of our farm trucks were dual ram set-ups. I crawled under the early 47, with a scissor hoist, thinking that it would have a reservoir into which I could add hydraulic oil (low on oil and wouldn't push the ram). I learned that the truck does not have a reservoir/surge tank at all. Could someone tutor me on how to put hyd. oil in this system without jacking up the bed and putting oil in the cylinder itself? Is it not desirable to have a reservoir in the scissor hoist system as the dual ram systems do? Can or should I add a reservoir?
Al

Early hydraulic systems have all of the oil in the main cylinder, no reservoir tank. I am not certain of all makes, but the Hercules brand has a fill plate screwed to the top part of the cylinder. You will have to jack up the bed with a bottle jack to see/assesses this area. The systems back then were very self contained and novel in design, cool in their simplicity.

Hello Paul, Thanks for your reaffirmation of what I thought about the scissor hoist. I can tell one thing, I will be repairing a couple of small leaks as I do not want to be messing with adding oil all the time! Is your Military truck a dump? (I don't recall)
Alan

Sometimes you can crawl underneath and access the fill hole from below. If you do have to jack the bed up, by all means be careful and be safe! I believe there is another thread here about blocking up a bed.
Also , if the bed is raised up, a good idea after filling it is to leave the cap off the first time you let the bed back down. That way if you've overfilled it the excess fluid can get out and you won't blow the seals out of your hoist.

Here is a link to a couple of pictures of the ram on my 58, I was also looking for a reservoir. It sounds like yours may be similar to mine. I laid under it and filled it with a quart bottle through the little elbow that is cleaned off. I think I put in almost 8 quarts.

http://i1152.photobucket.com/albums/p494/69B-Cuda/DSC_8633.jpg

http://i1152.photobucket.com/albums/p494/69B-Cuda/DSC_8639.jpg

Here is an image of the cylinder out of my 42 GI. This one was made by Hercules. Note the sheet metal cover held by 2 cap screws on the top rear part of the housing (barely seen in the image). I think all of the manufactures at the time used an internal reservoir design.

[img]http://www.surfacezero.com/g503/data/3285/medium/IMG_7491.JPG[/img]

Thanks 69Cuda, Rich and Paul for your images and observations. It is as I suspected, fill the cylinder. Does anyone have a cutaway view of one of these cylinders? I would sure like to understand how they work. I am guessing that one larger cylinder is around a smaller pressure cylinder with the pump being lower and has a supply from the outer cylinder, then through the pump and pressurizes the pressure cylinder and pushes the ram. Of course the flow is regulated VIA the control lever in the cab. Any other thoughts?
Al
PS: I am not sure I can worm under my truck with the bed down and fill the cylinder. I will study one more time before I bring in the front end loader to lift the bed.

on mine, I had to use a 1-qt oil bottle, with a 90wt cap on it with the tip cut off so it would not pour much out at all. Then I had to SLOWLY add it in (not even enough room to tip the bottle horizontal, had to have the top higher than the bottom and squeeze it. Once I got a couple qts in, I was able to get it to lift a tad more, then add another couple qts, and go up a bit more, etc till it would go up all the way.

Sorry, I don't have any cut-away diagrams.... I would also like to see one!

69Cuda, We got more snow, last night, so I am out of service messing with the dump truck for a few days. Then, when I can get under the truck without getting soaked, I think I will try to get some oil into the cylinder so I can raise the bed. I actually need to use the dump for a few days before I disable the truck for some serious update of the brakes.
Al

Al,

What brand is your hydraulic lift? Pictures?

On mine, inside the thick round housing is a large piston with 4 cast iron rings. The manifold valve pushes the piston in the upward direction and the oil is diverted through an external bypass tube for the downward cycle. It is a one way cylinder, no power down function just gravity. Refreshingly simple design.

I think once you lift up the bed with your front end loader you will be able to see where you can add oil. I used 10 weight hydraulic fluid and it took approximately one gallon. Just keep in mind that if the cylinder is low on oil it means that one or more (most likely all) of the packing seals are worn out. Don't kill the pump by running it dry.

Paul

Hello Paul, Did you get in on the big snow event that took place in the south and east? I will get a picture of the data tag for my hoist assembly and see if I can post. What is your email? My direct email is [email protected]. I can see where oil has leaked but I can't tell how bad yet until I can get pressure on it. I am treating the PTO pump nicely as I do not want any additional work/rebuilds due to not paying attention.
Al

I will try to share a photobucket ling to my GMC dump truck. This is what I am working with, both the truck and the dump arrangement.
http://s209.photobucket.com/user/alsfarms/library/1947%20GMC%20Dump%20Truck

Al

A lot of the older dump systems used plain old 30 weight non-detergent motor oil to power the cylinder, and as the piston rings and pumps wore, people would use heavier oil such as 90-weight gear oil to minimize leakage and increase the lifting capacity. This was not a particularly good idea!
Jerry

Al,

I have a paper copy of a parts "blow-up" image for a military Hiel lift. I bet they are the same or exceedingly similar. I will scan the image and send you an email.

Paul

Hello Paul, I am not very well versed on this forum, if you can't send a private email to me, I can be reached at [email protected] I will be very interested to see a cutaway sketch of the Heil Hydraulics.