Backhoe 758C backhoe ??????s

viperman · Nov 1, 2004

Hello, I have the above backhoe and for some reason it feels weak when moving side to side and trying to dig. It just seems to run out of umph. It does make a high pitch sound(like trying to squeeze alot of liquid in a small tube) when loaded. The stabilizer arms will barely pick up the tractor. I have not checked the oil level being that I just picked it up at the dealer (brand new) Any Ideas????

P.S. The loader seems to be weak also.

Also the left boom controller seems to stick when going down only.

pekabu · Nov 1, 2004

I have a 756c and left to right is fast, but not very powerful. As for picking up the back of the tractor it does it fairly easily. I believe if you push the left stick all the way forward it goes into float mode. So it should stick, but after you push through the detent.

PineRidge · Nov 1, 2004

Mine is a 757C and the stabilizers will lift the rear wheels of the TC-40D off the ground easily. I can drag the tractor using the boom itself to relocate the tractor. I normally run my backhoe at about 2100 RPM, if I go any higher on the RPM range boom movements can get jerky since they tend to move quicker. I only hear noises when I try to move an immovable object and the relief sounds off. (high pitch whistle)

If your problem exists with your loader as well you may have a problem with your relief valve. There are ways to check the internal hydraulic pressures.

Propertymaint · Nov 2, 2004

I have the 758C on a TC40D. I agree with Pine Ridge, have the relief valve checked. I also use the backhoe to move my machine around when I'm in tight spaces. The stabilizers and hoe should be capable of lifting the tractor. The swing on a backhoe typically is meant for swinging away dirt from a trench and not to grade off a 2ft berm. But you may have a problem with the pressure setting of the relief valve. Depending on where and what I am digging, I run mine between 1600-2000 rpm. It will give all the power the tractor is going to give without destroying it and gives a decent speed. Let us know how you make out. Also, the boom has a float position if you push the lever all the way forward. That is why it appears to be sticking. Takes a little to get used to.

viperman · Nov 2, 2004

Where is the relief valve located? And can I turn it up myself?

PineRidge · Nov 2, 2004

Viperman if it were me before I started tweaking the relief valve I would first find out what the internal pressures were so I might have a base line. Have you checked the pressure to see where it's at now?

I believe that New Holland tractors equipped with SuperSteer are considerably higher than those without the same option.

Non-SuperSteer Models TC35 through TC-45D are 1450-1520 psi (100-105 bar)
Supersteer Models TC-35 through TC-45D are 2030-2100 psi (140-145 bar)

RickB · Nov 3, 2004

I won't quote pressures off the top of my head, but ALL 40's and 45's are the same regardless of front axle. 35's MAY be a little less, but nowhere near 650 psi less. The high end pressure you posted is close, the rest are way off.

PineRidge · Nov 3, 2004

Guess I could be wrong but the pressures that I posted were listed as relief valve pressures in my New Holland repair manual section 25-3. The manual is the same for all Class III TC models.

Maybe those increased pressures are one reason folks with the SuperSteer option are not as opt to notice this type of problem.

jinman · Nov 3, 2004

( Non-SuperSteer Models TC35 through TC-45D are 1450-1520 psi (100-105 bar)
Supersteer Models TC-35 through TC-45D are 2030-2100 psi (140-145 bar)
)

PineRidge, those pressures sure sound familiar. Are they the power steering pressures? Did you look at the correct line in the table? Power steering pressure is the only thing I'd expect to be different for a Supersteer tractor. I can't imagine why the main hydraulic pressure would be set different. I think they are all around 2000 psi as RickB stated. /forums/images/graemlins/confused.gif

PineRidge · Nov 3, 2004

PineRidge, those pressures sure sound familiar. Are they the power steering pressures? Did you look at the correct line in the table? Power steering pressure is the only thing I'd expect to be different for a Supersteer tractor. I can't imagine why the main hydraulic pressure would be set different. I think they are all around 2000 psi as RickB stated. 

Whoops, It looks like I did quote power steering pressures Jim. Sorry! /forums/images/graemlins/blush.gif

Under hydraulic lift system pressures I am showing the following for system relief valve setting:

2275 PSI for a TC35
2500 PSI for the TC40
2500 PSI for the TC45