Belarus 520 hydraulics

We have a belarus 520 the hydraulic
cylinder goes up and down like its suppose
to but when u put anything on the arms
when it goes up it just leaks right back
off also when you hook anything up to any
of the hydraulic ports on the sides or the
back it shakes it but thats bout the best
it can do we cleaned the filters in the
hydraulic tank the cylinder has been
rebuilt and the hydraulic pump is new any
help would be appreciated thanks.

some of them have a T in the line to the back and you must close then off to use the loader or close the other one to use the rear outlets.

My Belarus I disconnected the loader hoses completely and plumbed in a new valve to get 5 hydraulics on it. 2 at the back, 1 is 3 point, the other 2 run the loader.
I have a 572 but much the same I think.

First thing I would do is follow the lines and make 100% sure they are hooked up correctly from side to side. Even go as far as removing the T in the line if it is still there. If arm goes up but leaks down the valve body may be letting oil back and needs replacing.
if you are like most Belarus owners you throw out the old valve and buy a new 3-4 spool valve and redo the whole thing.

here's a thought..on the 400 series there is lever/racket lock on the right side of the seat,very close to the fender side. if it is not all the way back the 3pt arms are non working or very weak/no load, remote outlets also not usable.
not knowing the machine, maybe the system has changed..for the better, however the book
says to disassemble/clean the distributor valve/re-assemble and adjust safety valve to operate
at 135+/- 5, kgf/cm squared pressure...now that's a number to work with...
The new valve "local" option works well also.
hope it helps.

If it helps any we think the original cause of all this is the back cylinder busted so to get it to the house it was locked in the up position which then started blowing fluid out the top which we know was definitely not healthy on it from the beginning

curious myself...this oil blowing out the top of what?, coming from a fill plug on a hyd tank/overflow vent fitting? can't be a tranny fill? [just making sure]valve body/spool entry?
kind of sounds like a line is being dead ended some how, was the broken cylinder raised up by hydraulic power and locked? by leaving the control lever in up position? or how was it locked up?
a jerking motion indicates a possible lack of oil, the filter has been cleaned and is in place correctly?
no rubber seal or filter plates in wrong position or direction, speaking of the 400 series.
just have to ask as i am not the expert and can learn something also.

If I remember correctly the oil was coming out of the dipstick. The leaking cylinder wasn't holding the load up when we had the mower behind it so we had to take the raise and lower valve and hold it in the upward position so we culd get it to the house. As far as I know we put the little disc filters in exactly as they came out after cleaning them out. Is there perhaps another filter that I need to check or something

evening: just thinking quickly, if oil was coming out of the dipstick...on the 400's this is a screwed in type of unit on the tank top...if oil was coming out there, it sounds like the threads could be stripped?
to strip them it would take pressure inside the tank and the dipstick being the weakest link..the oil comes out, better than having the tank expanded/burst.
It sounds to me that to keep the load up[ homeward bound] the raise lever was held up continually when it was trying to auto kick out as the cylinder limit was reached.
that would of put pressure on the system components[ dead headed], and possibly/has damaged the auto kick off/spool valve operation internals of the valve body/internals in general?
That comes back to removing the valve body and checked for a stuck bypass safety/spool damage/kick out operation, bent or stuck spool, broken spool spring. retainer clips, etc.
a long shot is maybe a piece of plastic that was a temp fitting covering/filler was not removed when the cylinder or lines were being worked on?
Also assuming that any lines remover earlier are back in their correct locations
Try contacting " Belarus.ca" for a hyd piping schematic, if you don't have a dealer you can contact?
i can check my 400 book and trace the lines, being they are very close machine, but may differ for sure.
hope it helps