I'm looking at a used dump bed to put on a old Freightliner I bought a while back. The used bed, the owner says needs the cylinder resealed. I've never been into a multistage dump truck cylinder, but I've done plenty of outrigger and beam and telescope cylinders, but they aren't multistage. Anything I need to look out for, or tips before I dive in?
Used to be a few years back it was more economical to just replace with a new one than to repack a used one as most of the time the stages were scored. Hoist cyliners used to be pretty cheap. I haven't changed one in 10 or 15 years though.
Never repacked one, but I've also never seen one that didn't leak.
They have to leak a certain amount to keep the entire stack of "V- ring seals lubricated, a common mistake is to crank the glands down too tight and the upper seals dry out and can score or "washboard" the cylinder stages.
If it isn’t scored up too bad, they are pretty easy to repack. Nothing to worry about.
I just bought one it cost me about 1800 for a 5 stage cylinder. I talked to an older driver and he advised me to just get a new one and said it will pay for itself many times over and that a new one will outlast a used one, he used to repack them and said don't waste your time putting it in and taking it out. He thought the older repacks don't last long enough due to the high wear they receive. It took me about 1 day to take it out and replace it. I had to cut a hole in the dog house, to get to the top pin. I had to cut the bottom pin loose I had to modify the new cylinder near the lower port because it was hitting the frame of the truck. Once the details were worked out, it was straight forward. It is nice not leaking fluid now. It is worth every penny..
Thanks for the responses guys, I really appreciate it. I went yesterday and looked at the bed with the leaking cylinder, the seller owns dump trucks, and the cylinder was gone from the bed already (no comment from the seller on it, it just wasn't there). The bed was on a truck that had been sitting in the weeds for 10 years, and although it was pretty solid, its really old, and been patched around on. And really lightly built. It was cheap, really cheap, but not what I was really looking for. I looked at two more beds today, and they both were better beds. One is in a little better shape, and its half the $ of the other one. Its bent up a little on one side, but I can straighten that out, and I think make it work. Thanks again everyone.
I use E&E hydraulic out of Union, for a small shop they do massive work, they generally rebuild three to five multistage cylinders a week, have the honing and inspection equipment to do it proper. The local shop running a large number of dump trucks opts to replace, faster simpler and warranted by manufacturer as well CHEAPER than the time down, labor expense to rebuild and the oft recurring leakers.
Multi stage dump truck cylinder stages are usually NOT chrome plated so they score and pit. You can repack them but IMHO a new cylinder would be a wise investment,