New to skids and the site , apologize in advance for the ignorance and if I didn't post in the right place. Just picked up a case 1835b uniloader in rough shape but was supposed to work as it should . But it doesn't. Fixed quite a few problems already and had my fingers crossed that they were my problems. Parking brake was stuck on and linkage missing . Fabricated new parts and fixed that, all axle bearings and drive motor bearing were shot, replaced all those , leaking hoses , fixed, instrument panel not working , fixed , although now the charge psi light is on which leads me to my problem. Engine (diesel) runs fine, goes forward and reverse okay seems a little weak but I have nothing to compare it too. If I try to turn it's very hard for it to turn and it squeals , turning right is worse than left . When I turn to the right the controls chatter badly. Loader works fine up/ down and dump. Just got gauges today to check charge pressure by removing switch and I have zero charge pressure , unless I'm doing something wrong or the new test set is bad , but I doubt it. Also the hose leaving the charge pump seems to be cavatating badly . Bad charge pump or could it still be bad tandem pump and how do I tell? Thanks in advance
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Sorry to hear you're having issues with a machine that was meant to work just fine....
Cavetation can be the cause if low power, plugged filters can be the cause of that, even bad/worn pumps can do it too.
I haven't worked on case machines, hopefully others can help as well.
Cavetation can be the cause if low power, plugged filters can be the cause of that, even bad/worn pumps can do it too.
I haven't worked on case machines, hopefully others can help as well.
Hotrod1830
Well-known member
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- Sep 14, 2010
- Messages
- 513
I would think that if the charge pump was working at all, you should see something on the gauge. They are gear pumps, so if they are turning there should be something on the gauge. By the looks of the parts diagram, the charge pump is the pump on the end(?) looks like the main shaft drives the hydraulic pump and the charge pump is locked to the shaft with a key.(verify by following the the hydraulic hoses and lines, charge pump will only feed tandem pumps) Could have sheared the key. Either way, you are going to have to do some exploring. Pull the end pump off and see if it sheared the key. If it did, disassemble the pump and make sure a pump failure didnt cause it.
Took the tandem pumps off , coupler is in tact , key way in tact, gear pump look like it's new to be honest , no wear at all. The pump behind it is definitely ok because the bucket works fine . Took the popet relief valve for charge circuit out it seems ok . I'm not sure what's going on. Still getting zero psi from charge pump , if I put sender back in charge psi light comes on . Changed fluid and all filters. There is fluid to charge filter and it pours out if I take sending unit out. How is it getting there if the pump isn't working. Could the charge circuit relief valve be bad and letting fluid bypass and not build pressure?I would think that if the charge pump was working at all, you should see something on the gauge. They are gear pumps, so if they are turning there should be something on the gauge. By the looks of the parts diagram, the charge pump is the pump on the end(?) looks like the main shaft drives the hydraulic pump and the charge pump is locked to the shaft with a key.(verify by following the the hydraulic hoses and lines, charge pump will only feed tandem pumps) Could have sheared the key. Either way, you are going to have to do some exploring. Pull the end pump off and see if it sheared the key. If it did, disassemble the pump and make sure a pump failure didnt cause it.
Have you hooked up a gauge to see what pressure you're getting and not just the sender?Took the tandem pumps off , coupler is in tact , key way in tact, gear pump look like it's new to be honest , no wear at all. The pump behind it is definitely ok because the bucket works fine . Took the popet relief valve for charge circuit out it seems ok . I'm not sure what's going on. Still getting zero psi from charge pump , if I put sender back in charge psi light comes on . Changed fluid and all filters. There is fluid to charge filter and it pours out if I take sending unit out. How is it getting there if the pump isn't working. Could the charge circuit relief valve be bad and letting fluid bypass and not build pressure?
The way the hydros are acting per your description would be consistent with zero charge pressure.Have you hooked up a gauge to see what pressure you're getting and not just the sender?
Had a so called mechanic come have a look at it, all he did was drive it a bit and said the tandem drive pump is bad. I asked him several times about charge pressure, he did if I had no charge pressure it wouldn't move at all. Again charge pressure light is on and no pressure where manual says to check it. Which is where the pressure sending unit is by filter head. He says there shouldn't be any pressure there. Then why is that where the sending unit is??? Does anyone verify that the charge pressure is built by the charge pump and then sent to tandem drive to supplement? How can no charge pressure mean the $3000 tandem drive is bad. I have no pressure after the charge pump before the tandem . Charge pump is good . Could it be the charge pressure relief valve?The way the hydros are acting per your description would be consistent with zero charge pressure.
I don't know the cat system, but with most systems, the returning oil from the main hydraulic pump gives the required charge pressure. If your main pump is not working, no lift or tilt power, it could be the cause.Had a so called mechanic come have a look at it, all he did was drive it a bit and said the tandem drive pump is bad. I asked him several times about charge pressure, he did if I had no charge pressure it wouldn't move at all. Again charge pressure light is on and no pressure where manual says to check it. Which is where the pressure sending unit is by filter head. He says there shouldn't be any pressure there. Then why is that where the sending unit is??? Does anyone verify that the charge pressure is built by the charge pump and then sent to tandem drive to supplement? How can no charge pressure mean the $3000 tandem drive is bad. I have no pressure after the charge pump before the tandem . Charge pump is good . Could it be the charge pressure relief valve?
Some systems do have a dedicated charge pump for the drive pump, the drive pump does not generate charge pressure on it's own. Where the sender is, you should be getting at least 90 PSI
Yep this model has a dedicated charge pump for the hydro drive ,manual says 100ps but I have nothing. Goes forward and back on flat land , struggles to climb hills forward or reverse , and struggles to turn to the leftI don't know the cat system, but with most systems, the returning oil from the main hydraulic pump gives the required charge pressure. If your main pump is not working, no lift or tilt power, it could be the cause.
Some systems do have a dedicated charge pump for the drive pump, the drive pump does not generate charge pressure on it's own. Where the sender is, you should be getting at least 90 PSI
have you found your problem?Yep this model has a dedicated charge pump for the hydro drive ,manual says 100ps but I have nothing. Goes forward and back on flat land , struggles to climb hills forward or reverse , and struggles to turn to the left
That is wrong, coming from personal experience with the 1835B. They will move, but not very well at all., he did if I had no charge pressure it wouldn't move at all.
I had a problem with weak to no hydraulics, would work a few minutes then stop completely.
ended up being a bad piece of rubber hose on the suction line to charge pump. Hose looked good but got hard and lost seal, let system suck air.
New 4" piece of 1" hose and works great.
ended up being a bad piece of rubber hose on the suction line to charge pump. Hose looked good but got hard and lost seal, let system suck air.
New 4" piece of 1" hose and works great.
Check You Tube. It has been a long time ago that I saw a video that sounds like what is going on here. It was fixed when he found a cut in a hose that was in the case in the middle. I think it ran from the charge pump to a fitting in case and out to the charge pressure sender. I can not remember what make or model he was working on.