Hydraulic lift arm control issue

[TLT]

I have a 09 B7800 HST with front end loader. The control to raise and lower the rear lift arms is different from other tractors. I’ve heard this referred to as the quarter inch valve. The lever has a center detent and a slow and fast lift or lower position. The fast position has always been too fast(implement will slam down or raise too fast). Now when raised using slow position, unit will stop lifting, and resistance is felt in handle to return to center. return handle to center and slow raise will lift a small amount, and stop again. Clear as mud?
Unit is functional, however I don’t think it has ever worked as expected or designed. Any information appreciated
TLT

 

[North Idaho Wolfman]

The round knob under the set will adjust the rate of fall of the three point, so the fast setting can be what ever speed you want it to be, granted this does not effect the rise time.

Now if the lever seams like it's binding and fighting you it's probably a feed back linkage issue.
You can go to Kubotabooks.com and download the WSM to help you with the adjustment of the feed back rod.

 

[lugbolt]

That is normal operation for that tractor. If you look at the lift lever and follow the linkages back to the 3ph, you'll find a rod with a spring on it that goes through an eyelet on the 3ph lift arm. When the arm rises, it pulls against the spring-which is supposed to return the lift lever to the neutral position. If it doesn't, and an operator just grabs the lift lever, pulls it back and leaves it, it will dead-head the hydraulic system such that the loader won't work until the 3ph lift lever is returned back to neutral. Deadheading is also hard on the pump, so that's why they put the "feedback" rod on it.

Your tractor is not considered an "inching valve" (or quarter inch valve)-as it doesn't have true position control. A lot of the B series were this way, all the way back to the B7100's that I can remember and probably further back than that. Kinda sorts similar to the old Ford's. Up or down and not much in between.