Another question about my Altec boomlift hydraulics

amanda11270 · Sep 10, 2013

For anyone who may have more experience with bucket trucks than myself, I am in the process of replacing some of the worn hoses. All of the ones that are worn seem to have bubbles in the outer skin. This guy at a local hose shop told me that its not the outer skin, its the inner hose that is what will cause the hydraulics to fail, he said the outer was just for abrasion resistance. Luckily all of my worn hoses are on what I would consider the lesser operations, like the bucket tilt, and also does anyone know what the purpose of this extra boom raise cylinder is for? It performs the same function as the BIG entire boomarm lift cylinder but its tiny. I cant imagine its for safety backup because its so little. Anyways it is the second hyrdraulic cylinder im rehosing due to old lines. You can see the bubble in the tilt cylinder line in the photo.

BukitCase · Sep 10, 2013

If lines have bubbles, it's coming from SOMEWHERE - usually means the hose is de-laminating and sooner or later will fail. Personally, I'd rather a hose fail on something I am NOT riding in...

Don't have a bucket truck (not for lack of trying :=) but you may find that the small cylinder is there to give you "auto-level" somehow - my case backhoe has one on the loader for that function. If you follow your hoses around, that small cylinder may be connected to your bucket tilt in such a way that, when you raise the boom(s) their movement extends/compresses that cylinder, which would add or subtract hydraulic fluid to your basket tilt circuit.

Doesn't look like tracing things would be very easy in that pic, but I'm thinking that's what you'll find... Steve

glastron23 · Sep 10, 2013

by the look of the pics i would say you have an AT series unit. the blistering comes from oil trapped between the outer cover and the inner liner. we find it happens to the smaller sizes of hoses (3,4 and 5). the oil leaks from the fitting crimps, the smaller hoses are harder to crimp properly and have a higher tendency to leak, we also find they will break the interior lining and leak, this happens mostly in areas that have tight radiuses and are moving back and forth in the inner boom cat track.
as far as the small cylinder on the side of the boom, it is the master bucket level cylinder. As the lower boom goes up and down it moves the master cylinder which in turn moves the upper bucket slave cylinder. there should be a bucket level valve in the bucket ( some have one at the lower controls also) this is to reposition the bucket or to turn it to help in cleaning it out.. Jim

glastron23 · Sep 10, 2013

just one more thing .. the bucket level system is a closed system,meaning that the oil in it from the master cylinder/pressure relief valves,hoses and slave cylinder dose not return to the tank as it is being used, once the system is filled with oil, it stays in this system. you will need to bleed any and all air from it to have it work properly. if you do not the bucket will be jumpy and not level properly.

amanda11270 · Sep 12, 2013

I feel like a bonehead now! Why did I not see that before, I was already thinking its a closed system once "BukitCase" said it was for bucket level and put two and two together. My truck has the bucket level feature and all the controls in the bucket are just toggle switches not valves. And yes you can tilt it downward to drain water and stuff out of it. I ordered a bunch of hoses, all the smaller 1/4 size, because they are all the ones looking like they have bubbles in the outer skin. All the larger size hoses that do the major functions still look to be excellent.
I work as a refrigeration tech, and im usually pretty sharp, but I just didnt put that bucket level and small cylinder together, thanks again guys!
I have somewhat of a manual on my Altec lift, I'll have to see if it gives details on bleeding the bucket level function, because im obviously going to have to drain it some to replace the faulty hoses.