pump is 36 meter schwing main raises very slow when extended out past about 50 degrees. Have seen the same on the other old 36's but still think it should be stronger. currently have to stop pumping rev up and wait way to long to bring it in.  when i engage the outrigger levers I notice the one on left (side the main is on) pressure stays lower be 500psi. aprox is it regulated lower?  three canister reliefs on that side witch to check first? 

Ok  found in manual = cartridge under outrigger lever 280 bar .  cartridge under lever to raise and lower boom  80 bar.

 Is that a type-O is that circuit regulated to that much lower pressure? And i guess that carteidge would be place to start trouble shooting.

Check the electric solenoid on the boom side,could be only partially open.Use to have this problem with Schwings in the 80's

The 280bar relief is for your max. system pressure it controls everything but Main down.  The 80bar (I would double check that almost all are 140bar) relief is for main down, to prevent boom or cradle damage.  The 3rd relief is in the dump valve (what bilsey57 refered to).  Is main still slow coming up if you run it from the stack valves?  You said it's an older pump, is the boom/outrigger valve in the proper position?  Are you in the correct gear?  It sounds stupid but you would be suprised.  After all of that has been verified bring the unit up to operating temp. at full RPM (which is how the hydraulic pump is designed to run, running at a lower RPM can damage a pump just as easily as overrevving) and with a GOOD gauge verifiy the pressure cut-off by "pressuring out" any section but main down.  If you don't get your 280bar. immediatly (it should not take 5 sec.)  leave it pressured out and feel the reliefs.  The one thats hot is where the problem is.  You can eliminate the dump valve by holding in the manual override, if that fixes it thats where the problem is.  If the problem is still there then it is either the brake valve, a holding valve or possibly a hose that is coming apart internaly.  Always start at the simplest part first.  What year is the unit, what hand valve does it have, etc.  Try this first and if you still have a problem send me a message and we'll get it figured out.

FIRED HER UP TODAY APEARS TO BE DUMPING AT CANISTER  (280 BAR) BELOW OUTRIGGER LEVER (LEFT) ADJUSTED SET SCREW RAISED FROM 220 TO 250 BAR SBEFORE IS BOTTOMED OUT. JUST GOT OFF PHONE WITH JASON  AT CONCRETE EQUIPTMENT INC. ON ANOTHER MATTER AND PER HIS ADVISE I'LL PULL THAT CANNICTER AND CHECK THE O-RINGS THEN SEE IF IT WILL ADJUST OUT.

pumped with truck today pressures fell thru the day. At end of pour I switched the cartridge on the problem side with the 280  bar  cartridge from the other side of controls, low pressure now on the other bank-- new pressure cartridge on order. thanks for all the input.

_{INSTALLED NEW 280 BAR  CARTRIDGE PRESSURE CAME UP. HOLDS 280- ALL THE WAY DOWN TO A IDLE.....}

GREAT JOB!