Since I have been running this boom truck (3yrs) I have noticed that when I have my forks tilted at about 80degrees and want to till the forks down further, if there is a fair amount of weight on the forks, once I start to tilt, the forks just fall to about 50degrees & then grabs. I know that it is gonna do it, so atleast I can expect it, but it can be a little unnerving when I have a unit of sheetrock 25' in the air trying to get it into a window. Any ideas? The guy that use to drive the truck told me that "it is normal & nothing is wrong" :Banghead . All I know is that the other 2 booms I drove over the past 7yrs never did that once. Here is the picture of what I am working with.
not normal. i would think you have a problem with the lock valve on the fork tilt cylinder or the tilt cylinder is leaking internally and needs to be repacked.
Thanks for the advice. I think I will do some digging around & see if I can find anything out of the ordinary on the cylinder. Not sure if it matters, but if I have a light load on it, it doesn't "fall". So maybe at a certain weight, that lock isn't strong enough to hold?
Between this & my outrigger cylinders maybe needing to be repacked - I better come to the boss on a good day. Although if it needs fixed, he always had said "fix it - doesn't matter how much because it needs to be done." Got a great place in Deer Grove, IL called Cylinders Plus that I have taken my truck to get cylinder work done & they have a great turn around time & great work!
Agree with dbl612, I wager that the cylinder has counterbalance valves that are faulty. Just a guess though as I know nothing about those booms.
The way I see it - for the most part, hydro. cylinders all work the same. So if you guys have great knowledge about cylinders, I will take your word.