Insufficient boom down pressure, won't raise tires.

210-B---H. Greetings, it's me again with another question on this old (1959) backhoe. It has two hydraulic systems (loader and hoe). All of
the hydraulic functions are working well except down pressure on the boom. Which would've been real handy when I got it stuck in mud (did I
mention it has no brakes either?) and had to call in a neighbor with his newer, etc. Case hoe to get mine out (he had a little trouble too).
Per my Case shop manual, I've set the 'main relief valve' for the hoe at 1600 lbs.(calls for 1650 so I'm close). Set the in line boom 'flow
control valve' at two turns open from stop (book calls for 2-1/4 turns).
I'm using genuine Case hydraulic oil (books call for 10w heavy duty non-foaming).
My somewhat limited experience with backhoes was with newer equipment. So what do I know, maybe this old horse never did raise the tires off
the ground with the boom .. doubtful, the stabilizers will.
If you guys are gonna tell me I need to go into the Hydreco Control Valve body, (!!) - I'm old and have never had a garage.
As I stated in an earlier post back in Aug.; I bought this old tired horse for a job to do, not restore necessarily except as needed.

Backhoes generally have boom down pressure set down so as to protect the operator from getting into trouble raising the unit enough to make it dangerous, did u check the boom down pressure while you had the gage in circuit, When I was employed I set many boom down pressure reliefs up enough that operators could pick the rear up and swing the hoe over a ditch. Some early hoes had an inline relief in the pluming for some circuits, this served the purpose of protecting the systems from overload from prying forces pushing back on other circuits and creating pressures beyond what hoses and cylinder barrels could stand. Follow your boom down cylinder hose from the cylinder butt end back to the valve to see if it goes directly or through another valve before it gets to the main valve, better yet post some pictures of the valve and hosing so we can see if there are any external secondaries used on those models.

I set 'main system pressure' (1650 lbs. off of 'dipper arm')(much easier to get gage in line, most of boom cylinder buried in boom arm).
Case sells, or use to at least, factory preset repair kits for individual valves. Really don't want to think about pulling valve body 'out in
the field'.

Can you send me a picture of the top of the valve where the spools come out, if the valve has secondaries on the boom down hose it could be adjusted if much lower than system pressure, it looks to me that you could check boom down pressure on the hose end of the flow control valve. If the control valve has secondary cartridges ( they are right along side of the spool, have a domed nut on top) they are adjustable. The low pressure secondary can be set with a pressure gage only because it is set at a lower pressure than main. Is 1600 the recommended system pressure for that series hoe? Generally the mfgrs will allow 10% so you could could go to 17 and that would be a noticable increase.

This drawing appears to be mislabeled in that too numbers are given for boom valve.

Another pic from another source. I need to read up, but it appears to me due to tension spring, valve has to come out the bottom (if that's the problem). Which is another problem - removing the valve body or manifold out far enough without a complete disconnect being necessary.

if your stabilizers wont raise the tires off the ground then you have a problem. not sure you have a problem with your boom

The stabilizers do raise the tires off the ground. Everything else except the boom down pressure works fine. The down pressure on the boom tries but doesn't have enough.

I assume these are the steps you followed to set the set the main relief. That said I have a 420B Case hoe,, a couple steps bigger than your 210B is,, it is set at max psi and does not have the boom power to lift the rear end and move the machine like the later 530CK/580 ect has,, never did it will dig just fine and do all I ask and more, I do not think at the time they wanted them to have that much down pressure on the boom,, I scanned the pages for mEl and pinball to see if they did not already have them available, this is for the mode 21 backhoe
cnt

CN, thank you! I see that they do not call for a separate low pressure secondary for boom down, I would check the pressure on the boom down hose just to be sure. The later hoes such as the 580 c series had a digging pressure I think ear or above 2000 PSI but set boom down at 1200 Or in that area to limit the ability to raise the rear with the boom for safety reasons.If the pressure is the same boom up and boom down then the machine is doing all it can do at that pressure

Yep same shop manual that I have Case Nutty. Thanks everyone. It's as I wondered then; it never did have the design or capability to raise the tires with the boom. As I stated, it does everything else I need it to do. Note to self; stay out of deep mud.