L4150 Loader problem - please help

Cdnhogman · Sep 17, 2009

I have a Kubota L4150 that has a loader problem. When the oil gets hot the loader does not raise or lower easily. It sometimes goes up and down slowly and sometimes not at all. It will raise and lower if I turn the bucket while trying to raise it up, but that is frustrating as anything in the bucket falls out. The oil is clean and topped up and I have replaced the hydraulic hoses feeding the loader and removed the quick connects. Any suggestions on what might be causing this problem?

rbargeron · Sep 18, 2009

Does the loader actually work at normal speed when cold - but go slow only when warmed up? If so it sounds like maybe a worn pump. Assuming it's a BF900 Loader, the valve recirculates the oil when curling the bucket. But if curling the bucket makes a difference to the up-and-down motion, the hydraulic lines between the valve and loader might be mixed up. Have you had this tractor a long time?

Cdnhogman · Sep 18, 2009

I have had the tractor a little over 9 years - it came with the house. The tractor had 1200 hours on it when I got it. I am assuming they were hard hours as the previous owner had a foundation company.
The loader works fine whe it is cold, it starts working bad after about 1/2 to 1 hour of use in the warm weather and a little longer in the winter. I have repacked the bucket cylinders because of minor leaks, but the loader cylinders don't leak so I left them alone. By use I mean just running the tractor, it does not necessaraly mean using just the bucket.

Wayne County Hose · Sep 18, 2009

In my experience, most of the time, the pump is bad. When it is cold, the clearances shrink allowing it to build pressure. When it heats up, the clearances increase. I would verify by checking pressure. Another thing you can do is run it a few minutes and feel how hot the pump is. If it gets hot real quick, it's probably bad.

rbargeron · Sep 19, 2009

I agree it sounds like a worn pump. The hydraulic oil also looses some viscosity as the tractor heats up, aggravating the increased pump clearance. Unfortunately a new Kubota pump (35430-82202) is around $1k. Maybe there's a rebuilt version available somewhere.

Cdnhogman · Sep 19, 2009

Thanks for the replies.
$1K is a lot of money, so I want to be sure and try everything before committing to a big repair bill.
How can I check the pump? The dealer is about a $300 tow from here (each way) so I would like to check it out in my yard if possible.
Is it possible that the problem is in the control valve? I forgot to mention that it is very difficult to get the boom into the full float position.
Also, I have been using Massey Fergeson hydrulic oil (tyhat dealer is a 2 min drive from me). Could that be the problem?