Control unit on ford 753 backhoe

[spooly123]

I have a Ford 753(series) T9-389(component) 3827(serial) backhoe mounted on a 1966 Ford model 4000 numbers C1Z76ZZ 6BZ 440Z16 gas 3cyl tractor.
This means it is a 47 year old machine, but it still digs and works. My problem is that there is a pretty good hydraulic leak coming from the backhoe control unit located under backhoe seat. I have replaced about half of the hoes, but the rest are original. The leak seems to occur when I am pulling the arm back toward the tractor under pressure. It does not seem to be leaking where the hose connects to the control unit. My questions are is there any other place it could be leaking besides the hose connection??? Is there any place where I might purchase a new or reconditioned control unit????

 

[joecdeere]

there are seals in each spool, along with if it was a multi piece valve there were o-rings between each section

here's a look at the one piece style

 

[spooly123]

Thank you very much.....

 

[LD1]

I will say it is very hard to pinpoint leaks on a control unit/spool assembly. the seals arent that expensive, I'd replace all the ones on the spools for sure.

And they might not be standard o-rings either. Not sure on yours, but my 5500 valves had quad seals. Which is kinda like an 0-ring but a square-ish cross-section

 

[J_J]

You could be leaking from a number of places.

Here is a suggestion.

Clean all the fluid from the control valve.

Go to NAPA or wherever and get some fluorescent dye and put in the hyd system, and use the BH a while. Work each function.

Then in low light or darkness, use a black light and shine it on the control valve.

The leak should fluoresce and glow yellowish green.

Each spool has three opening, top, bottom, and load check valve.

Each port. IN, TANK ,maybe PB

A pin hole in a hose.

Bad fitting.