View Full Version : Rebuilding a Fisher MM

Brett K
08-03-2005, 09:51 PM
I just bought a truck 99 Chevy 3/4 ton with a 7.5 Fisher MM. First thing I have to say is....Holy Crap! That sucker is HEAVY. Had lots of fun unloading it from the bed of the truck. It seems the plow wasn't maintained well at least in terms of appearance. I will be sandblasting everything, repainting, and replacing every nut, bolt, and pin. I tried hooking it up. It didn't do much other than click. It took a while of banging on things to to get it to raise once up and back down. I have a few questions before I start...

Where can I find a good large assembly schematic/manual? Most that I have found are too small on the screen.

Are there any while you are at its I should be taking care of since I am ripping it apart?

08-04-2005, 05:42 PM
Fishers website has the same mechanics guide that the installers use in the equipment shops, runs you through all parts and repair/troubleshooting.

Couple of things to check,

base angle, dont let it wear into the mounting points for the trip springs, very expensive to repalce.

A-frame pivot point, check for wear and slop in the pin, with the plow hooked to the truck and raised you shouldnt be able to push on end of the blade down much more than an inch.

Hoses, fluid and filter, check hoses for crackes or chafing, replace the fluid and filter (filter is inside of cases on front of pump).

cylinder rods, check the lift and turn cylindrs for pitting on the rods, excessive pitting will chew up a packing seal, get back to the pump and plug the filter along with just leak expensive fluid.

As for it not working, check with you battery conections ( + and -) at the battery, solenoid and at the pump, check you grill conectors for corrosin, sloppy pin sockets and missing pins,(should be 9 pins), fi that doesnt solvie it let us know exactly what it does and doesnt do and we will go from there.

and make sure you use a good primer/sealer before you paint.

08-04-2005, 05:48 PM
Crash,good toubleshooting.Brett let us know if you need more help I have fisher as well and hopefully we can get you fixxed up...

08-05-2005, 08:25 AM
Also in the plugs from the plow to truck make sure the pins are clean and use di-electric greese (lots of it) to keep the pins from corrodeing. Make a tool to slightly spread the pins apart- I took a stubby flat blade screwdriver and ground the blade to an edge- works perfect. You want to only spightly spread the pins to make sure the make contact. (fisher dealer gave me the idea from a tool he made). Also check the plug end at the blade side- prone to wire breakage with age. Fisher sells replacement ends.

Brett K
08-08-2005, 01:24 PM
Thanks a bunch guys. I plan on doing a little problem solving before disassembly as soon as I get a chance. Your posts have already given me a headstart. As soon as my neighbor hooks me up with his sandblaster, I'm gonna give this a go. Should make a nice fall project and keep me out of trouble.