Does anyone know how to lower a bucket truck if the engine fails or a hose breaks?

[migraineman]

I have a 1984 Asplundh aerial lift on an F-700. A few times a hose has blown and caused the bucket to get stuck in the air. How do you get it down?

 

[B.G. Smith]

There is a check valve in the "up" fitting of the hydraulic cylinder. It is tied to the "down" side connection of the cylinder and requires pressure from the "down" hose to open the check valve and allow the release of fluid to lower. This is a safety device to prevent the bucket/boom or whatever from falling should the "up" hose fail. Some units have a battery driven pump to lower in case of engine failure but the only way I know of to lower the bucket if the hose breaks is to repair the leak. Sorry I couldn't be of more help. bg

 

[FFutch]

Replace the hose if at all possible. I work for the local power co. as the garage mechanic. These hydraulic systems do not like air. I've heard of cylinders getting enough air in them that they've free fell 10-15 feet and ruined somebodys day. We have all Altec stuff. The only time you should use the electric pump is if the engine dies and then only for a few minutes. If all else fails you might be able to plug off the broken line to get down unless of course its for the down position. I know that our diggers have an inline "fuse" in them in case of a line blowout to keep the boom from falling. Hope this helps,Doug

 

[illflem]

I had some kids from the Job Corps come out and trim trees, they had a brand new $35k tow behind lift. I asked about the one lever a little ways down the boom from the bucket, they said it was to let it down if something broke. Might want to go look at a new one and see how it's plumbed. Might be cheaper to replace hoses when they look like they might fail. I've had many pieces of equipment that would go though hoses, best solution was to make sure the relief pressure isn't set too high and protect the hoses from kinks and rubs. What worked great for me was to slip the hydraulic hose though sections of old fire hose, free from many fire stations or Forest Service.

 

[migraineman]

Thanks for the replies. I think I'll replace some hoses. It looks like the old hoses used fittings that screw together rather than being crimped. Can these be safely re-used?

 

[illflem]

I only used the screw together type for low pressure returns to the tank. Don't really trust them especally when they are on a hose that moves, had one come apart, that was enough. The crimp ons are cheaper, you just have to go to a shop that does it, which can be a hassle but better than fixing one twice.