Went to start up machine yesterday to find no hydraulics. Serial no 710A-157-514-18794-88. It was running good a couple weeks ago then it sat. Weather was cold for a bit then warmed up to around 0 celcius when I started it. Everything is operational except hydraulics. Hydraulic oil was a little low so I topped it off to no avail. Am I looking for a electrical issue? Not sure where to start. Any help would be appreciated. Thanks
We got one we use on the farm every once in a blue moon 720 A and it started doing the same thing if it sets for a long time make sure the suction hoses are good and clamps are tight ours has got enough wear in the pump that it doesnt want to pick up oil took the breather out of the tank and put a hose on it and put a little air pressure on it [a little] and the pump picks it up and away she goes . But check those hoses and clamps first.
Nothing electrical on those systems. Does it have the pump driven off the front of the crankshaft via a short shaft? If so check the integrity of the splines to make sure everything is turning properly.
Yes, the pump is driven off the crankshaft. It seems to be turning fine from what I can see. I will take the pressure washer and clean the area off and inspect the hoses and clamps and tighten them up if needed. Thanks Guys.
We had a similar issue with our grader. It would loose prime as the hydraulic tank was lower than the pump. I usually just poured oil in the suction tube If it had sat for a while
Hi everyone. Tried pressuring up the hydraulic tank with air tank with machine running and got nothing. Had a second person in cab pulling lift cylinders back. I'll probably cut into the hydraulic filter tomorrow and check it for metal. The machine is 200 feet from shop so I might pick up the front end with excavator and walk it over to shop so I can wash the rear end off around the pump.
Is the transmission functioning ? Not sure where the trans pump is driven on a 710.
Yes the tranny is functional.
Again check the drive shaft to the pump under the radiator.
I see the drive shaft spinning. I was reading the Sierra park link with all the different manuals and it shows the the pump as a three section unit with the steering pump section on the outer section. Steering is functioning fine.
Cold weather sure plays havoc on gear. The water is the hydraulic reservoir came out of suspension and froze on the bottom, blocking the supply. Warm up the old girl and and everything will work fine. I seen’t it !!
Here is the page on the hydraulic pump
Coaldust. I'll give it a try, thanks.
Sorry everyone on the crapy pictures. I'll have to get some help with this.
I do hope it’s that simple. Good luck. Keep us updated.
your shaft coming off the engine goes into gearbox that turns pumps correct ? are the pumps turning ?
Yes. The machine has steering and according to the info I see online that pump is the outside pump with shaft going through the three segments. To me that tells me the shaft is not sheared or splines wore out.
Until I wash that pump area off I don't really know how many pumps are stacked together. There is also a pump under the injection pump that I have no idea what it controls?
The first and second pictures are from rear of machine. The third is under injection pump.
The one under the injection pump should be for the transmission.
Is there a test port somewhere up by the valve body to put a gauge on?
The later ones did away with the gearbox and just had a straight shaft driving a double pump.
Not certain on a 710 but you could try cracking one of the pressure lines at the pump and see if it’s moving any oil at all.
I cracked the small top one on the right side and had oil flowing but I suppose I should have had someone in the cab turning the wheels to see if it started to spray with somme intensity. Just thinking out loud here.
And when you say no hydraulics, that's wheel lean, side shift, rotate, MB tilt, all that stuff. My old 730 had a belt driven pump as well, no idea what it did.
Yes. Thats correct.
Our 730 lost wheel lean, but it was an issue with the valve body under the cab, it would never affect everything. Find the line that supplies the main valve. Not sure if yours is in behind the stump guard, or on the goose neck. Ours had debris in the out going line. but you could hear the pump trying to lean the wheels, but it was blocked.
Ok, thanks cutting edge. When I operate the controls I don't hear the pump at all and can't feel any pilot pressure feeding back to my hands. Not sure if one should feel pilot pressure. I have not run graders before.
These do not have pilot controls. Straight cable actuated valve spools.
OK. Do you have a drawing of the valve block test ports to show where one can check the pressures?
I guess I should get of my butt and see if I can put some new dents and cuts in the top of my head trying to see up in there. I'll get back and report a little later.
The controls in your hand operate the functions via cable. There is no pilot system, but there should be a pressure supply line from the pump to the valve bank. My issue was from the valve for the wheel lean to the front axle. A piece of the hose it self came off and blocked the line.. I have no knowledge of test ports, but if you knew where the supply line is for the vb, you could crack it. It should be quite a spray..
I cracked a couple of what I think are the feed lines from pump and didn't get any spray. I picked up the front end of the grader with excavator and backed up to shop and got the pressure washer going. It was dark by the time I finished cleaning the back end of machine. The weather is going to get colder for the next 5-6 days. I don't have a shop to put machine in so I may run out of time to work on it. We will see.
So on the first 730 I ran, roughly 1990, and I’ve forgotten the serial #, my understanding was that it had a double sided pump under the rad for steering, brakes, and transmission. And the hydraulic pump was off the bellhousing. Somewhere along the line Champion switched stuff around to run the hydraulics straight off of the crankshaft and moved the transmission pump to the bellhousing. Twisted off accessory drive maybe?
Sounds like either the pump isn't turning or there is a large leak on the suction line. You should be able to determine if the pump is turning just buy putting your hand on it with the engine running. If it is turning, then the problem is either suction related or the pump packed it in. If the line directly off the pump doesn't have flow then check if something might be blocking the suction or the suction line is bad. Not sure but could a lever for (aux.) Hyd's accidentily been engaged and it's taking all the flow? I only say this because on a skid steer it can happen but the machine is much harder to start under load.
I guess another thought is something could be stuck in the relief valve holding it open.
From the amount of wet gunk under that pump im thinking suction leaks
I couldn’t reconcile what I was reading in the service manual on the Sierra park site and what I was seeing on the machine. I crawled all over and under the machine and everything was telling me the back pump was for tranny and steering and the pump off the auxiliary had to be the implement. While the machine was running I cracked open the auxiliary fitting and oil started to come out. The engine pulled down as the pump finally loaded up with oil. I jumped into the cab and everything started to work again. Boy that sure felt Good!
Lost it’s prime. Glad you found your problem.
Good deal!.......but fix that suction leak or it will do it again. The hydraulics may be a bit jerky if the pump is pulling air into the system from the suction side.
Yes, I got in there and tightened up all the fittings, When the weather turned cold the hoses would have shrunk plus it was sitting for a couple weeks. It was a good time since the covers were off to tighten the radiator hoses which were starting to leak.