L355 SS 3 point hitch wont lift

[HoneyBadger]

I have recently purchased a L355SS. It has 600 hours, 4X4, L1720 loader with its own hydraulics reservoir and pump (mounted at the bottom of the front below the radiator). I replaced the Hyd fluid and filter for the loader. I just replaced about 2 weeks ago the transmission/hyd fluid for the tractors the old walkinky, no, not good (8.8 Gal). I believe that the 3pt is powered by the tractors trans/hyd fluid, not the loaders pump and reservoir (correct me if I am wrong). About a month ago I was able to lift a bush hog with the 3pt, but it did have some initial hesitation and drove it back to the house about a mile. I had replaced the fluid before I went and picked up the bush hog. I just purchased a box blade, backed the tractor up, lowered the 3pt to line it up. It was a little low so I went to raise it slightly and that's when it wouldn't go up at all. I pulled it forward, gave it more gas, nothing, wouldn't raise an inch (nothing attached). I got off and was able to lift the 3pt arms very easily by hand. When I changed out my fluid, there were 2 fill pugs and either 5-6 drain plugs. I believe that I replaced all fluids but I am a newbie so that I could have missed something. The 3pt does have a lift and a draft lever. I am attaching a picture of a plug that I am not sure of its purpose. I doesn't look like the plugs for the transmission. I has an O-ring on the plug itself. The second picture is looking down where the plug goes and the last is a knob taht is dirrectly below the seat that I do not know it's use (any info there appreciated as well. Sorry for the long post but I know the more info the better. Thanks for the help!!!

 

[North Idaho Wolfman]

I do believe that plug is either a Pressure relief valve or a bypass plug (you would remove it and pipe in another separate valve.)

The valve under the seat controls the speed of the three points down movement, try turning it to lock and back to full and see if that helps anything.

 

[HoneyBadger]

Thanks Wolfman, I had turned it all the way to lock (about 3 revolutions if I remember correctly) then back to the F (fast i'm assuming) which is where it was before, then backed off a 1/4 turn. I will definitely try it again when I get home.
Thanks

 

[cabhopkubota]

Wolfman, My 3 pt lift would not go up forever then today it went up (had the levers up position just in case) while using the loader on my 355ss. Could not figure why they would not go down, took the plug (by pass shown in picture above although mine does not have a ball on the end) out and nothing happened. Read your post so I checked the F S Lock and mine was in lock position. Soon as I began to turn the valve counter clockwise to the F position the arms went down as should. Thanks Cabhopkubota