M371 hydraulics and high range seems to smoke belt

[brucefenster]

The hydraulics on my borrowed m371 seem pretty weak. I can only move one direction at a time ie roll or raise the bucket but not both at the same time. I know the lifting capacity is only 500lbs but it doesn't seem to want to lift any weight at all. It is also VERY slow. I've asked in another thread about belt sizes as I'm not sure if I have the correct combination but we do have a new belts on the the machine running the pump as well as the low range and they seem like they should work. I'm using hydraulic fluid for a larger backhoe (10w I think- its free from a friend) not ATF or engine oil. What should I be using? Besides hydraulic power being weak and slow all the time it seems when we attempt to run the machine in high range the belt, which is the same one driving the hydraulic pump, slips and starts to burn. Any ideas? Thanks Bruce

 

[Jim Z]

Unless your machine has been modified, the hydraulic pump should have its own belt and have nothing to do with the drive belt. Mine has a 3/8" belt close to the frame (inside the drive pulleys). I run light hyd oil (10w) because we use the machine year round. Med weight in the winter slows the hydraulics to a crawl. Suggest you replace the filter and make sure the oil level is full. If those are not the culprit, it may be the pump. The pump is obsolete but Honor Pumps makes an adaptable, cheap replacement. Good luck!

 

[brucefenster]

Unless your machine has been modified, the hydraulic pump should have its own belt and have nothing to do with the drive belt. Mine has a 3/8" belt close to the frame (inside the drive pulleys). I run light hyd oil (10w) because we use the machine year round. Med weight in the winter slows the hydraulics to a crawl. Suggest you replace the filter and make sure the oil level is full. If those are not the culprit, it may be the pump. The pump is obsolete but Honor Pumps makes an adaptable, cheap replacement. Good luck!

Thanks again Jim. As you point out in another thread I might actually have a 310 not a 371 as this does have the high low range selectable with buttons. Or perhaps we have a hybrid. Maybe a 371 that has had the 310 clutches installed. This actually makes sense as we can not believe the factory would design the belt that runs the hydraulic pump to only engage the pump pulley a quarter of the way around. Anyone have pictures of their 371 on the web that I could see and help identify what we have. The belt setup would be interesting. Also may a way we can positively identify the difference between a 371 and a 310 on way or another?