No lift with weight in bucket

Hello, New to the forum but glad to find you all. I have a Prime Mover L1000 skid steer. From what I have seen it was made in the mid 80's in ND and called a Rounder. When I throttle up I can lift and tilt the bucket empty. However, when I get dirt in the bucket, it will not lift. Everything worked fine and then I noticed it getting weaker and now it just won't lift with weight in the bucket. I have been told that a bypass valve or something like that could be stuck open allowing the bucket to lift with no weight in it, but not creating enough pressure to lift when the bucket is full. Does anyone know of how I can try and diagnosis this and see if it is a valve. Hopefully it is not the pump itself. Oh, the drive motors work just fine and are strong. Are there 2 seperate pumps? Thanks

I would check the relief valve too, it should be screwed into the control block.
Does it have aux hydraulics? could they be stuck on? this will cause no lifting power.
If its hydrostatic drive it will have two drive pumps and one hydraulic pump.

Tazza said:

I would check the relief valve too, it should be screwed into the control block.
Does it have aux hydraulics? could they be stuck on? this will cause no lifting power.
If its hydrostatic drive it will have two drive pumps and one hydraulic pump.

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Thanks Tazza for replying. I see you post often and are very helpful to many people. I was hoping you would see my problem and offer some suggestions. I have some mechanical skills but very little with a skid steer. Is the control block where all the hydraulic lines originate from under the seat and cab? It does have aux hydraulics, nothing has been attached. How can I check to see if they are stuck on. I see the two drive pumps on each side, they are working fine. I'll look at the control block. Anything particular I should be looking for to identify the relief valve, such as shape,etc... Thanks so much

GGibson said:

Thanks Tazza for replying. I see you post often and are very helpful to many people. I was hoping you would see my problem and offer some suggestions. I have some mechanical skills but very little with a skid steer. Is the control block where all the hydraulic lines originate from under the seat and cab? It does have aux hydraulics, nothing has been attached. How can I check to see if they are stuck on. I see the two drive pumps on each side, they are working fine. I'll look at the control block. Anything particular I should be looking for to identify the relief valve, such as shape,etc... Thanks so much

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I don't know your machine, but some use a steering lever that you move from side to side to engage the aux hydraulics. Yours may be the same? It should be able to be wiggled side to side and return to centre where you want it to be.
The relief valve should screw into the block that the lines go to that control lift and tilt. I think you have it, the one under the seat with the bunch of lines.

You will only be able to see part of it, the bottom half screws into the control block. It should look something like that, it may have a screw to adjust pressure, they are all different but operate the same.

Tazza said:

I don't know your machine, but some use a steering lever that you move from side to side to engage the aux hydraulics. Yours may be the same? It should be able to be wiggled side to side and return to centre where you want it to be.
The relief valve should screw into the block that the lines go to that control lift and tilt. I think you have it, the one under the seat with the bunch of lines.

You will only be able to see part of it, the bottom half screws into the control block. It should look something like that, it may have a screw to adjust pressure, they are all different but operate the same.

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Thanks so much Tazza. Sorry for the delay in responding back. I will look for the relief valve. I have also been told that perhaps one of the lift cylinders may have blown a seal and is not lifting, leaving all the lifting to just one cylinder and that's why it won't lift when the bucket is full. I do have one cylinder that has been leaking slightly but I was told it could have blown seals inside and not leak much but still be pretty much useless. What do you think - possibility?

GGibson said:

Thanks so much Tazza. Sorry for the delay in responding back. I will look for the relief valve. I have also been told that perhaps one of the lift cylinders may have blown a seal and is not lifting, leaving all the lifting to just one cylinder and that's why it won't lift when the bucket is full. I do have one cylinder that has been leaking slightly but I was told it could have blown seals inside and not leak much but still be pretty much useless. What do you think - possibility?

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For a cylinder not to lift due to a bad seal is a stretch. If a seal goes, it will let oil pass by the piston, but the pump can supply far more than will leak past the seal. Another member had an issue of the nut coming off the piston, it caused issues close to this so its possible something like that has happened. A good test for this is to remove the front pin to the ram with the arms lifted and locked into place. Operate the hydraulics and see if the lengths of the sticks are the same at full extension.
I hope that finds something.....

Tazza said:

For a cylinder not to lift due to a bad seal is a stretch. If a seal goes, it will let oil pass by the piston, but the pump can supply far more than will leak past the seal. Another member had an issue of the nut coming off the piston, it caused issues close to this so its possible something like that has happened. A good test for this is to remove the front pin to the ram with the arms lifted and locked into place. Operate the hydraulics and see if the lengths of the sticks are the same at full extension.
I hope that finds something.....

Click to expand...

I had an internal seal go on one of my hydramac cylinders.. it would lift, and then drop down. it was weird.. I could lift a bucket of soil, up to 5 feet and it would settle down to about half, and hold that position. I also have a holder, with a snow blower on the front end like a 3 point hitch. one piston on the end of the shaft of one lift arm blew apart. I could lift, but I had to constantly have the oil pumping to keep the blower off the ground.. I had to drive home 4 miles like that, at 18 miles per hour.