Ford 723 backhoe - control question

I am doing some R&R on my old Ford 723 backhoe model 19-301 (14' dig). It has many cracks to weld and needs the swing post replaced. Those I can do but it also has an operating issue that I am not exactly sure what is the root cause.

When operating, the boom drops very rapidly unless you just feather the control. It gets to be exciting if it drops fast as the whole machine then jumps when you back off the control and the boom stops suddenly.

There is a one way flow restricter in the line from the boom cylinder that is supposed to slow the drop speed. Initially I thought that was the problem, but it is there and has the sliding sleeve.

My other thought is that the check valve or spring inside the spool is the issue.

I'll be taking the control apart and checking, but what should I be expecting to see?

If that isn't the problem, what else might it be?

Thanks for helping the hydraulically challenged!

jb

Just got the dipper stick, boom and platform all separated yesterday. Got the swing post off this morning and started taking out the bushings for the swingpost from the platform. Lots of wear there. I'll post some pictures of the damage to the swing post. It's the most damaged piece of metal that was still in use I have ever seen! Good thing I have a decent replacement.

jb

It was repaired in June of this year for some rather nasty cracks. Most had been repaired before, but the dumb sob didn't chip slag between passes and the (ahem) weld didn't hold. I really don't know why some people even try if they don't know diddly about what they are doing. Ground it all out and welded it much better. I knew it wasn't a permanent fix as the main pivot was still ugly and needed to be removed to do. I went and got a spare SP as I didn't think the original was worth the effort of saving. Lucky it went as long as it did!

jb

• Picture link

I made the tooling to repair the swing pin holes in the swing post . The one I made the

tooling for was a 765 , but the pictures look

somewhat similar. I do them for the local

ford tractor dealer ,I'm the only guy in the

territory that has a milling machine big

enough to do it .I have a 3 inch spindle Lucas,

it is a horizontal boring mill .

I you need a picture of the tooling, I can send

some to you .

george

Interesting!

I noticed last night that with the swing post off, the mounts on the body of the hoe that hold the SP are bent. Well, the middle one is bent down about 1/8" maybe 3/16". It's also cocked off to one side. Hard to tell exactly how much it is out.

Any thoughts on what to do to fix?

Thanks!

jb