Fire service ladder truck

Well I have my friend's ladder truck so that I can put a new rain cap on one of the smoke pipes at my church, except he told me that I would have to fix it first. I finally figured out how to get at a micro switch that was rusted closed, and got it freed up. Then I tried it and after some backs and forths I finally got the stabilizers out but now the right one, which has a good load on it, won't retract. Up on the platform the turntable will shift back and forth a little in the cradle but the ladder won't raise. It is looking to me like there are check valves that are hanging up. It hasn't been used in about a year and a half. It has plenty of oil in the hydraulic tank, I suppose I should see if I can find a drain on the bottom and check to see if it appears contaminated. The manual says that the filter will bypass so it can't be causing a problem. It also has a low pressure light on the dash that comes on if the hydraulic pressure gets too low. A couple times the pump has made some noise like maybe it is laboring but never a low oil noise. When I operate the valves for the stabilizers I can here the change in sound as the oil rushes through and then doesn't, even though the stabilizers aren't moving. Any ideas?

Are there lock valves that would be
actuated by a microswitch or such to
prevent lifting the stabilizer if theladder
isn't down etc. Many cranes and such have
such interlock setups. I would be looking
in that direction if it were mine

Next time borrow a truck that works!

(quoted from post at 09:39:00 06/08/15) Are there lock valves that would be
actuated by a microswitch or such to
prevent lifting the stabilizer if theladder
isn't down etc. Many cranes and such have
such interlock setups. I would be looking
in that direction if it were mine

Click to expand...

The main lift cylinders have them in line main line to the cylinders so that it can't drop if it loses pressure. I suppose they may block the oil from entering the cylinder as well.

I agree, one of our local fire companies is having this issue right now with their ladder truck. Company came and looked at it and said to repair the lockout they may have to remove the ladder assembly, VERY EXPENSIVE. Hope you have better luck. We were going to use the truck on drill night to put a new cross on top of the local church for 100 year celebration, happy it broke before not during that job. I was able to put the cross up with a 40' extension ladder.

I finally got everything working pretty much as it should. The stabilizer freed up when I operated it up and down in slow speed. The spool valve for the hoist was frozen up with rust. I got it freed and worked it back and forth with plenty of oil. Once the hist was working, if a stabilzer gets hung up I can just swing the ladder to the other side to take the weight off and it frees up. From studying the manual I found that this model doesn't have pilot control valves on the stabilizers like some do.