FEL weak down pressure -- valve assembly hisses

[jim_galloway]

Hi folks--
I have a '03 B7800 with a 402A front end loader. The loader recently started getting weak applying downward pressure. Sometimes the only way I can lower the loader is to push the control lever to the float position and allow gravity to help. After I shut the tractor down and restart, the loader seems to work better for awhile. I noticed that there is a hissing noise like air from a tire in the valve assembly when moving loader.

I read a few threads about problems with relief valves in the control valve assembly, but I figured before I go poking around with something totally new to me, I ought to post the symptoms here to see if I might get a quicker diagnosis.

Thanks for any advice...
Jim

P>S. I checked HST fluid level and it looked good -- it was between the two marks on the indicator stick.

 

[Goin Camping]

Jim, did you find the fix? I have a B series machine that has started doing the same thing.

 

[kennyd]

It could be just a bad or improperly seated QD (Quick Disconnect). Try unhooking all the hoses to the FEL and re-seat them.

The relief valve set the MAX pressure to the valve-I don't think it would cause the problems you described.

 

[blueriver]

Just for thought ... is there even the slighest damage to either cylinder? Last year one of my tractors with a FEL got weak I checked everything ... from pressure to valves ... I then used a second tractor and hooked the hoses to it, still the same results, I was unaware of damage to the cylinder housing and was told that the fluid was by passing through the cylinder. After examination I found surface damage, took it to the local machine shop, they rebuilt it and have been good since!

May not be your case, just wanted to put that in there!

Todd