AUTO CRANE 6006h want boom down

[chris allen]

Hello guys, was doing some cylinder repair work on a loader other day an when we got threw with the job I started to sit the crane back down onto the truck pedestal but it wouldn’t boom down. Had to use a lull to hold the crane up while we dropped the boom cylinder down so we could lower the crane down to bed of truck. I have power to the boom down function, done checks the coils, checked the spools for down function, even switched them with differ ones, looks like the load lock valve isn’t getting enuff press to override the safety loc an allow it to lower. I can see the cylinder flexing but no oil flow . I’ve replaced the counter balance valve already a pump was built few yrs ago, running a vein pump with a 8-9 gallon a min cartridge in it. Boom down is the only function that want work. I know it requires more hud pressure to boom down an boom retract in. Boom retracts in an out fine. It’s not any of the load limit switch’s , every thing electrical safety wise is not on it. All
Been removed. Been working fine for 15 yrs Done talked to 2 different auto crane dealers wasn’t much help other than they said I’d have to bring it in for them to look over. I tryed takeing it to them yrs ago for them to fix all the electrical safety stuff. But like always they never call ya back or seem to not wanta try to schedule me takeing it 2 hrs up the rd to there shop. Told me to drop it off an try to work it in. Honestly don’t have time for my service truck to sit on there yard for a month or so. Or longer. Hopefully someone on here is familiar with auto crane cranes. First pic is the serial number to the crane. An other pics are the boom cylinder that I’ve got removed a laying on back of service truck, made up long test hoses . Truck is equipped with a proportional valve under the bed, Pressure there is around 2200 psi area (working pressure)

 

[Mobilewrench]

I had a problem with my 4004 last year when it wouldn't boom down. I'm not sure if yours is set up like mine, mine is about 20 years old and the hydraulics run off of an electric motor mounted on the tank on the side of the crane.
Usually it was a problem with either the interference switch on the end of the boom or one of the solenoids going bad. But last year it ended up being the suction screen being sort of plugged up in the tank. Guess it got enough oil to raise the boom but not enough oil for the pressure required to defeat the safety switch. I'm glad that was it because after checking the simple stuff I have suspected that the piston had come off the rod.

 

[chris allen]

I’m pretty familiar with ur electric over hyd unit. When I worked for cat my service truck had one on it. It was always going through electrical solinoids and burnt wires an getting the electric pump motor built few times. Decided then I’d never run one again on a regular basis. Hopefully it’s don’t give ya the same fits. If ur electric motor ever goes out, ya can take it to a local starter/ alternator repair shop. Don’t think clogged screen is my issues. Mine has return screen in top of tank

 

[Mobilewrench]

Yeah, that is the way I remember the way that 6006 was set up that the cat dealer had me in a few years ago. But I thought I would reply anyway. At least this way if someone has a problem with a unit more like mine the info is out there.

My unit has been pretty trouble free other than the issues already mentioned. I had to replace the turntable bearing a couple of years ago, that was a chore. And I finally had to reseal a cylinder on it.

My main complaint is how the power and ground are set up. The ground just runs through a bolt on a spring that rides on the slew gear and the power is delivered through a jankey assed brush in side the turntable.
Recently it has developed a couple of dead spots where everything stops and I have to rock the crane back and forth to get contact. I keep intending to hard wire the power and ground (who has time to work on their own stuff?) but It keeps not happening.

 

[B&B]

Hello guys, was doing some cylinder repair work on a loader other day an when we got threw with the job I started to sit the crane back down onto the truck pedestal but it wouldn’t boom down. Had to use a lull to hold the crane up while we dropped the boom cylinder down so we could lower the crane down to bed of truck. I have power to the boom down function, done checks the coils, checked the spools for down function, even switched them with differ ones, looks like the load lock valve isn’t getting enuff press to override the safety loc an allow it to lower. I can see the cylinder flexing but no oil flow . I’ve replaced the counter balance valve already a pump was built few yrs ago, running a vein pump with a 8-9 gallon a min cartridge in it. Boom down is the only function that want work. I know it requires more hud pressure to boom down an boom retract in. Boom retracts in an out fine. It’s not any of the load limit switch’s , every thing electrical safety wise is not on it. All
Been removed. Been working fine for 15 yrs Done talked to 2 different auto crane dealers wasn’t much help other than they said I’d have to bring it in for them to look over. I tryed takeing it to them yrs ago for them to fix all the electrical safety stuff. But like always they never call ya back or seem to not wanta try to schedule me takeing it 2 hrs up the rd to there shop. Told me to drop it off an try to work it in. Honestly don’t have time for my service truck to sit on there yard for a month or so. Or longer. Hopefully someone on here is familiar with auto crane cranes. First pic is the serial number to the crane. An other pics are the boom cylinder that I’ve got removed a laying on back of service truck, made up long test hoses . Truck is equipped with a proportional valve under the bed, Pressure there is around 2200 psi area (working pressure)

I had a 5005eh have an issue where I think it was the boom down function wouldn't work until you extended or retracted it while booming down and then it would be fine until it sat for a while again and you'd run the 2 functions together and it'd free up as long as you kept using it

 

[funwithfuel]

So your oil is changing direction via solenoid valve, correct? You have oil to power down side? The only thing I could see preventing a cylinder retract would be the logic or load holding valve having a piece of trash on it preventing it from opening. Be careful, the trapped oil inside vould be under a lot of pressure. Good luck.