Possible issue with my Ford 730 loader.

I originally posted this in the Ford forum but I am reposting because I am not quite sure whats happening and it its more of a general hydraulic issue I think.
Here goes.

The tractor is a 1973 3400 with a 730 loader.
The arm and curl circuits work great, both have great breakout and great down pressure. If I lower the loader to the ground then uncurl I can lift the tractor up and it will stay. With a full load in the bucket it will not drop down.
My fluid levels are correct and there is no air as observed by no jerking when operating.

My possible issue is that if I uncurl the bucket and lower it, when the loader lowers the bucket to the ground it will just curl the bucket. Like I said, if I lower this down and then use the curl I can manipulate it however I like(normal operation). It only happens when I lower the loader down with the bucket uncurled.

I dont have a picture of the control valve handy but it is a 2 spool open center with no float detent.

Here is a video to try and explain the issue.

I feel like it has got to be something in the valve since that is the only thing that connects them, but it works fine in every other circumstance.
https://youtu.be/gixzer662gw

So in the video, after the bucket curls up, of you tell it to uncurl, will it still thrm lift the front of the tractor up at that point?

To me I just see a lot of slop in the loader pivots and some air maybe in the bucket cylinders, it’s just a little sloppy but everything is actually working fine?

Paul

Yes after it curls up from lowering the loader I can uncurl and lift the front. It acts like air but I don’t get any jerking or jitters when operating. The loader has some slop but not enough for half the curl. When the bucket is full of a load and I’m full curl I can controllably uncurl to dump. There’s never an over center tipping point. Just uncurls at the speed I tell it with the controls.

It’s really odd. I think it only happens with no weight on the curl cylinders.

I'm with Paul on this maybe some air and slop.

Turns out it is a Cross SBA valve on it. I think it must have some sort of internal leakage in the valve since it does not operate like there is any air or noticeable slop in the system. I've been using it for dirt work at my house, this specific issue is the only issue every other situation it works fine. It must "seal" up somehow when you increase the pressure to the curl rams?

Like I said with a full load of dirt, when dumping there is no tipping point like if there was air or huge amounts of slop. It just uncurls and dumps controllably.

I will continue to just use it because it's not a huge deal, just a really weird failure.

cross has manuals on the internet.