4000 HD ind backhoe hydraulic help

[mike bruns]

I"ve got a 1965 4000TLB in poor condition. I put a new hyd pump on and changed all the filters and fluid. I checked the pressure at the backhoe valve manifold and it only has 1700psi. The relief valve was screwed all the way in and the spring is smashed flat. I added some shim washers and ran the valve in and out. It would back off pressure but never made more than 1700psi. The loader valve has its own relief thats not adjustable at 2000psi.The loader valve feeds the backhoe but does it"s relief effect the whole system. It might be wore out and dumping before the backhoe gets full pressure. Thanks Mike

 

[john_Bud]

As you surmise, the loader relief does impact the whole system.

If the loader pressure is set to 1700 (worn out or set low), the the max pressure in the system is 1700 and screwing in the hoe relief won't help any.

 

[mike bruns]

Thanks John. I'm going to try taking the loader releif valve apart and see if I can shim it.

Most all of my machinery would be scrapped by now if it wasn't for these forums and people willing to share their knowledge. Thanks a lot.

 

[Ecnerwal]

Call me crazy, but I could swear mine (4500 TLB) is plumbed backhoe, then loader. And indeed, my backhoe assembly manual specifies the power-beyond [b:4a4c44ec39]from[/b:4a4c44ec39] the backhoe as going [b:4a4c44ec39]to[/b:4a4c44ec39] the loader, not vice versa. So you may have a wrongly plumbed one (the one I have without the hoe is horribly wrongly, or rightly for some other interpretation of rightly plumbed.)

Backhoe relief is supposed to be 2200 +/- 50 psi. Setting it a shade low may be kinder to old equipment, but that might be 2100, not 1700.

Loader relief is supposed to be lower. 1600 +/- 50 PSI, assuming it's a 740 loader. They are prone to breaking without having the relief jacked up, so jacking the relief up to 2200 is almost certain to end in more loader frame welding...

If connected in the correct order, loader relief pressure has no effect on backhoe relief pressure.

I suggest replumbing it correctly so the backhoe is fed first, and the loader is fed from backhoe power beyond.

 

[daman]

on a 4500 TLB it's oil is sent to the backhoe [u:c84771c5e9]first[/u:c84771c5e9]...then the power beyond circuit feeds the loader valve then back to the reservoir.

back hoe is set to 2200 and loader is set to 1800ish.

 

[john_Bud]

(quoted from post at 19:04:38 08/27/10) on a 4500 TLB it's oil is sent to the backhoe [u:538227f723]first[/u:538227f723]...then the power beyond circuit feeds the loader valve then back to the reservoir.

back hoe is set to 2200 and loader is set to 1800ish.

This it's backwards from the stuff I have. Good to know.


If he can't get over 1700, then the pump may be the issue with it bypassing internally.

 

[daman]

(quoted from post at 12:44:47 08/28/10)

(quoted from post at 19:04:38 08/27/10) on a 4500 TLB it's oil is sent to the backhoe [u:b965c371a6]first[/u:b965c371a6]...then the power beyond circuit feeds the loader valve then back to the reservoir.

back hoe is set to 2200 and loader is set to 1800ish.

This it's backwards from the stuff I have. Good to know.


If he can't get over 1700, then the pump may be the issue with it bypassing internally.

At least on a 4500 like i said,,but yea if he's limited to 1700 that's low he has pump problems/wrong pump or somthing going on or valve body problems.

 

[mike bruns]

my loader control has a port marked out feeding the hoe.I assume power beyond.It also has a non adjustable relief stamped 2000psi.I'm guessing its worn and tired.My pump is new and sized for the machine.
The 4500 looks like a lot more advanced machine than my 4000.
I'm going to the hyd shop moday to get releif springs. If I can't get the loader relief to stay shut i'm considering jamming it closed and using the hoe relief for everything.
My loader is poor but I really need the hoe to do some digging.

 

[daman]

Yea ok the 4000 obviously is a different animal.

 

[john_Bud]

(quoted from post at 17:10:34 08/26/10) I"ve got a 1965 4000TLB in poor condition.

Does it look like this?

Or this?

If so, it's older than your listing of '65.

 

[mike bruns]

yeah,sorry it must be a 1964. The last of the 4 cyl engines.
I verified the plumbing yesterday and tried to seal up my loader control valve. It has some serious leakage from two round plugs on the bottom. I thought it was the hose fittings but I resealed them and it still leaks. I'm sure the spools and internals are worn out.I don't mind the leak I just wonder if I could have a pressure loss inside it.