yes i have the workshop manual
What part does the accumulator play in your system. Might be totally irrelevant, but in other system I know, the accumulator is used to supply hydraulic pressure to the brake system. Is there something in your manual about a shuttle valve that will release the brakes when hydraulic pressure is up for normal operation. Anyway, this valve can be a source of trouble.
An accumulator is just a storage tank for pressurized fluid, and the out flow can be used for many things.
You did not say whether you had a hyd test gage. I suggest all hydraulic run system have one for trouble shooting.
We really need some more particulars to help. Tell us what you know about the hydraulic system, hydrostatic transmission, hyd gear pump, FEL, 3pt,etc
Does the engine run, is any hyd function working?
Have you checked all filters?
Hydraulic fluid level.
How many pumps?