pc 200-8 hyd problem

i have several pc200-8 excavators i run hyd hammers on.I am haveing alsorts of hyd problems expically the solinods on the pump and merge flow valve. If u are having these problems to let me inform u of some handy info.Put magnets in ur hyd tank u will be suprised of the fine metal that will be on them when u remove them.then change your hyd filters every 250 hours,this includes the pilot filter,hammer return filter and the main hyd filter.Change ur hyd oil every 1000hrs also.before u change ur hyd oil take a hose and loop ur hammer circut together and run the unit for several hrs to circulate the oil threw the filters then pull filters and discard them. Install new filters and oil this will keep the dealer from staying on ur jobsite and paying them high repair bills. U may think this is a expensive procedure, ya it is but compare it to the repair bills u will get its very cheap in the long run.If u have a after market hammer system make sure it has a filter on the return circut it is required by komatsu or it voids machine warrenty.if your machine hyd system runs slow the are 3 solinods on the pump and 2 on the merge flow valve. These 5 solinods are all the same.If u take them off pull the 2 screws out of them hold them parell with a flat,clean surface and hinge them apart. the plunger in the block will b stuck, u should b able to move them with minium pressure.if they wont move tap them lightly this will break them lose.remove plunger and spring and there maybe a small shim,clean with a good arrisal cleaner and reassemble.Inside the solinod there is a plunger make sure u put the plunger in the way it comes out they are not always the same.You can clean these about 2 to 3 times then its time to buy new ones.hope this helps u guys that are having problems with ur units.