PTO GOING BAD? Electric back up issues

1st thing I would try is unhooking the trailer hydraulics and seeing how the truck worked with the PTO at idle (Most Cottrells are setup that if you don't set the tractor brakes, the engine will stay at idle.) I'm guessing the pressure relief on the trailer valve bank is bad and things will work fine. I don't know anything about East Coast Truck and Trailer except heresay, but I believe they are in Portsmouth or close by.

If the PTO is sucking air from the engagement line, it shouldn't affect the electric backup. That would have to happen on the suction side. You could probably hear that with the truck off and the pto engaged by putting your ear close to the tank opening or against the side of the tank, you'd hear the bubbling. I suppose it is possible the PTO is totally shot and bleeding pressure back to suction side, but if that were the issue, you'd think the rack wouldn't work either.

 

Oh, I misunderstood! I thought you meant the back up pump was engaging but not working on the trailer. Just use a bungee to hold the tractor switch up while you need it.

Now the I'm sober, there's no way for air from the pto to get to the hydraulic pump. Two separate devices bolted together. But it is possible to suck air, but you'd almost have to have a bad suction hose for that to happen. There's not much suction pressure, especially with new filters.

 

Sometimes the logic valve goes bad. The large bolt pointing upright on top of the valve bank. I have had to switch the valves around from bank to bank to get it to work. They wear out and it controls how the hydraulics use the oil pressure to lift in the bank of valves.

 

Curious how this turned out? What was the problem?

Its been so long now but could you engage your electric pump at the truck side and then work your trailer hydraulics? Curious if you tried that at all too.