Altec at37g boom quit working

[Micheal Starkey]

Hi, I'm new to the forum and would appreciate any help I can get.

I'm working on an altec at37g bucket truck. I replaced the transmission and started it up, engaged the pto and was able to raise the bucket and extend it out. Then the pressure hose from the rotary joint broke. I replaced the hose, but the boom functions will not work now.
There are no outriggers on this unit, so no safety's there.

So far, I've-
Replaced all hoses to turret (pressure and return lines) from pto to rotary joint
Replaced suction lines (tank to pto)
Had pto pump checked (its good)
Rebuilt pto (friction disks,wave springs, plates)
Checked flow (5gpm)
Bypassed rotary joint
Cleaned valve body /valves (lower controls)
Cleaned pressure relief valve
Added external filter (tank to pto)

Nothing has gotten this thing moving again. The tilt works very slowly and left/right rotation works, but the lower arm does nothing and the upper arm looks like it's trying to move, but doesnt. Bucket extension also does nothing.

I've also tried the d.c. pump, the unit functions exactly the same with it. Any help would be appreciated, feel like I'm beating my head against a wall with this truck.

 

[Bls repair]

Oil full ?bleed out air? Any change in pump sounds when operating controls ? Any change in pto shaft speed when operating controls?

 

[Bls repair]

Tank to pto filter may have slowed flow down so can’t build pressure.