JD 675b hydraulic charge light

[jchilcot]

I just bought this 94 JD 675b. I was plowing snow with it last night and after running it for awhile the hyd. charge light came on. Everything operated as normal. I stopped and checked the fluid level and it was full.
I shut it down for a few minutes and started running it again. The light was off for awhile then I lifted the bucket up on a little of a downward slope and the light came on again. This is exactly what happened the first time. What could be causing this?

 

[Z2898]

The hyd light will come on when the pressure difference across the filter is high enough. The light is there as an indicator to tell the operator the filter is restricted (or plugged). When the difference is high enough oil will bypass the filter element and continue downstream to supply circuits as unfiltered oil.

3 reasons this can be happening. 1-the oil is too cold and has a higher viscosity and therefore will not go through the filter element, increases pressure on the inlet side and overcomes the bypass valve spring value. 2-the filter is dirty. 3-the bypass switch or the valve spring has become weak.

If you dont know when the filter was changed I would start there. You may also have to change hyd fluid to a lighter viscosity for winter use depending on the ambient temperature you plan on operating your machine in.

Hope this helps,

Z

 

[jchilcot]

Yes that makes sense. When I checked the fluid it looked pretty thick.

 

[Cobra-R]

Most commonly on those machines was the charge pressure sender would go bad. If it is weaping a little oil, that is a sure tale sign.

Brian

 

[durallymax]

We had a 675B since new until this year. One of the more reliable machines on the farm, probably the most reliable.

We always had issues with the suction screen. It would either be plugged, or sometimes iced up due to water getting in the system. However when it would plug youi would have no hydraulics and a very noticeable growl. If youy remove the panel behind your feet you will see it. Long canister.

 

[smokey1]

Cobra is right on, The sender is located at the oil cooler input line about $17.00. Very common failure

 

[jchilcot]

Thanks guys that sounds exactly like what mine is doing. Ill check it out.

 

[jchilcot]

Does anyone know the part number for the hydraulic suction screen? Mine is pretty dirty and Id like to replace it. I cant seem to find info on it anywhere.

 

[jchilcot]

So I have started to use the skid steer again since spring has finally arrived. The charge warning is still coming on. I cleaned the suction screen. It was pretty dirty. I thought for sure that would fix the problem but it hasnt. I dont think its the sender due to the way it is running. I have noticed that it will work fine until I lift the boom a couple times. Then it comes on and stays on. Everything seems to still work ok but the boom lowers slowly and the engine loses power if I start to work it hard. I have read a trouble shooting guide for the machine and what I got from that is it could be the pressure relief valve. Any thoughts on that? The hydraulic resovoir is full.

 

[durallymax]

Relief valves can weaken overtime and cause the system to go over relief more easily, but it generally will only show up when you are working it somewhat. lowering the boom is not working it.