Posted by Bonehead on April 07, 1998 at 14:00:04:
In Reply to: Re: Re: Re: Re: Re: hydrolic problem posted by GEO on April 06, 1998 at 19:36:36:
: :
: : : :
: : : : : : If I pull the handle to make the loader go up it goes slowly. If I pull the lever about 1/2 way, it goes as fast as you woul expect. Also, if you put the bucket all the way up, it will come down on its own fast enough to see it then it slows down, then it will drop fast again. It seem to have certain spots were it willcome down, maybe a foot in a couple minutes. Can be handy for setting poles by yourself, but hell if your trying to work out the bucket.
: : : : : The more I think about it, it sounds like the piston seals have blown out of the lift cylinders, if they are two way. The lifting that you are doing is by displacing the rods out of the cylinders. One way to check this out is to raise the bucket off the ground about a foot or so and unscrew one of the hoses at the end of the cylinder that the rod comes out of. If the loader trys to settles the rest of the way down, you will need to have the piston packing replaced.
: : : : :::Very interesting, could you explain in more detail, how you lift "by displacing the rods out of the cylinder". Always trying to learn, Bonehead
: : : In the case of one way cylinders, the rod is the piston. When oil is pump into the barrel, it forces the rod out. This is why on most one way cylinders the rod is larger. However on a two way cylinder, you have a piston on the end of the rod and when oil is pump in on, say the bottom of the piston, the piston forces the rod out of the barrel. If the piston is leaking and oil is bypassing, the oil is simply being recirculated back in the system. However if oil is being pumped in faster than it is leaking pass the piston some lift will result. But when the flow of oil is cut off then the rod and piston leaks back down till the pressure is equal in both lines. This is why if you have lifted the bucket a foot or so off the ground and you crack the line loose on the rod end of the barrel oil will be forced out by the rod reentering the barrel. If the piston seals are not leaking and you lift the bucket off the ground and then crack the line loose on the rod end of the barrel, there would be no pressure. All the
: : : pressure would still be in the opposite side of the piston. I hope I have not confused everybody, I am not a skilled writer. I am just trying to put in print what I know or think.
: : : GEO
: : ::::I think that was very well written and explained. Do you have any idea's on why, when the control is pulled 1/2 back, the bucket raises faster than when pulled fully back. (My skills do not include writing either, but isn't this fun)
: : Bonehead
: One reason would be if the control valve is directing fluid into the bottom of the cylinder more than it is allowing fluid to return at the half way point. When the handle is pulled all the way back fluid is allowed back in as fast as it is being put in. In the event that the piston seals are bypassing the return oil is being resricted at the half way point, causing the cylinders to move faster than they would if oil is allowed to recirculate freely back in the system. In other words if the control valve is restricting the return oil a little at the half way point the two cylinders are acting like one cylinders because the rod it self is being force out of the bore. When the valve is pulled all the way, oil is being pumped in below the piston, the oil is leaking by the piston and is going back in the system.
: GEO
:::: I like the theory, now if Joe would just
let us know, after repacking the cylinders (or having them rebuilt) if that fixed the problem.
Good job, GEO and good luck Joe, Bonehead