Dead Cylinder???
The GOAT 12-14-2010
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Looking for some insigt on why our rock valve wont swing as hard as it should. Last trip we took the truck out we had a pretty harsh mix and we couldnt get it through the boom. We re-charged the accumulator and after that it still seems that the rock valve is hesitating when its time for it to swing to switch cylinders. I'm wondering if we might have a dead cylinder or if the bladder in the accumulator is bad. Any insight would be greatly appreciated.
biged 12-14-2010
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On my Putz the accumulator has to be charged at 1,450 lbs, do you have a gauge to check it with, also your s-tube could have build up grout either in front of the cutting ring or at the rear of the s -tube making it tight  on the cutting ring, will it shift without any mud in the hopper.
pump031 12-15-2010
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Sounds like your bypassing oil somewhere, check your relief valve. Or if you are having a lazy shift you could put a bigger orface in the shift cyld.
gboom 12-15-2010
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dont be changing orifices! the hyd. system on your pump (I am assuming you have a Schwing) has been proven to run, so if you decide to change anything, it can interfere with other areas of your system, i.e. you better know what you're doing! if you're suspecting a leaking rock cylinder, take the tank line off and run it into a bucket, retract the cylinder and see how much oil is coming out, should be ~ 5 liters/min.; check your bladder again, you may have a pin hole and it is loosing pressure really slow;check your hyd. pressure gauge, see how far it drops at the shift, is the hyd. pump keeping up with the demand?; check your signal lines to the S3, pressure?

as you can see there are a lot of things you can check before you decide on waht the problem is
gboom 12-15-2010
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all of my suggestions apply not only to Schwing pumps, this is basic hydraulic trouble shooting
bisley57 12-15-2010
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Do you know how to check the pre-charge pressure on the accumulator?
gboom 12-15-2010
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you need an accumulator charge kit, if you don't have one, a local hydraulic shop can probably help you
Many 12-16-2010
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Acc pressure,check ?

Check ball on shift cyl ?

S-3 spool/spring ?
gboom 12-17-2010
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no springs in S3 spool, but 1.5mm orifice drilled through, check springs at MPS