Fisher plow creeping

philt

LawnSite Member
Location
NH
Just purchased a 1988 f-350 with a 9' fisher that creeps down. Would this be linkage adjustment, piston or pump. What is the best way to trouble shoot? Thanks
 

DaveO

LawnSite Member
Location
N. Dighton MA.
Philt,

Could be piston, valve body, hose, or cable adjustment(way off). The pump is most likely OK, if it can lift the blade. Once it is lifted, it is the valves job to hold the pressure in the line, to keep the blade up. Any leak will cause it to drop. Is it a electric/hydro setup or the belt driven pump style. The more info the better...

Dave
 

BRL

LawnSite Bronze Member
Location
Somerset, NJ
The website for Fisher is http://www.fisherplows.com/ They don't really have a section at their site to pose technical questions. The site tells you to talk to your local dealer about service questions. You can find your local dealer through the site. I contacted the Fisher "experts" and they weren't much help. They don't even offer a service manual like I've seen for other plows. Stick to hitting your local dealer with the tech questions.
 

thelawnguy

LawnSite Silver Member
Location
Central CT
My Fisher came with a combo owners/service manual. 50 +/- pages. If I find it Ill post up what they recommend.
 

thelawnguy

LawnSite Silver Member
Location
Central CT
What type of control, hydraulic underhood pump/cable or SEHP?

Check for leaks at packings and fittings, on SEHP systems the 2 way valve, if damaged or defective will be the culprit.
 
OP
P

philt

LawnSite Member
Location
NH
Thanks for the tips,
The unit is hydraulic under the hood with cables.

philt
 

Alan

Member
>>Lift piston seal<<

Probably not. That's a single acting cylinder, if the leak was internal to the cylinder there would be oil coming out around the pushrod seal when the plow leaked down. If ti was double acting you could have leakage around the piston itself and never see it on the outside, but not on a SA cylinder. Check the cables first, make sure they are adjusted to allow the valve to close completely. If nothing else, lift the plow and unhook the control cable at the valve end. If it keeps dropping, problem is in the valve, if the settling stops then the problem is in the cable, which is holding the valve open slightly.
 

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