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proper use of carrying chain

Discussion in 'Residential Snow Removal' started by Megunticook, Jan 21, 2008.

  1. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Own an older Fisher "speedcast" era plow and was wondering about the proper use of the carrying chain. Are you supposed to let the lift cylinder hold the plow up, with the chain just as a backup to prevent a sudden drop, or are you supposed to put the control in the "float" position so the full weight of the blade is held only by the chain?
     
  2. plowman4life

    plowman4life Senior Member
    Messages: 557

    fisher are chain lift. they are supported by the chain only. so put the control in the "float" position so the full weight of the blade is held only by the chain
     
  3. mayhem

    mayhem PlowSite.com Addict
    from Peru MA
    Messages: 1,016

    No matter what you do with the lift cylinder, the blade is supported by either the chain or the ground. The lift cylinder raises the yellow triangle, which lifts the chain, which lifts the plow blade.

    When transporting on truck, just raise the plow all the way up and go.

    Float position (at least on my newer style Minute Mount) is no pressure on the lift cylinder so the plow rests on the ground and the cylinder can retract as far as possible.
     
  4. shanta74

    shanta74 Member
    Messages: 72

    i think what he is talking about is the safety chain for transporting a long distance. the extra single chain. and with mine i always just used it a back up i still kept all the weight on the ram.
     
  5. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Right--Fisher I believe calls this the "carrying chain" as opposed to the "lift chain."

    If the weight is supported only by the carring chain, then you have the full weight of the blade being supported by a single chain welded on to one side of the A-frame. With the weight carried by the cylinder, then you have the carrying chain attached to both sides of the A-frame, which would halve the stress on the chain. On the other hand, your seals in the cylinder are constantly under full load--but I guess they're made to withstand that. I have noticed that the blade will eventually creep down while driving in this position, even with my brand-new OEM cylinder.
     
  6. mayhem

    mayhem PlowSite.com Addict
    from Peru MA
    Messages: 1,016

    My mistake, sorry about that.

    My chain has probably been replaced at some point in my plow's life before I bought it as I have no chain apart from the lift chain...hence my confusion.

    FWIW though, my lift doesn't go down whatsoever while driving, even if I go a good 35-40 minutes.
     
  7. justme-

    justme- 2000 Club Member
    Messages: 2,138

    Actually, no the seals are NOT designed to withstand that and they are only under full load when you lift the blade, which puts full load on the lift cylinder seals and valve block seals.

    The reason the chain is done the way it is on MM systems- 2 lengths for the lift ram one for the carry is to allow self adjustment and simplify manufacturing. It's a single piece of chain bolted in 3 places through a ring on the lift triangle- one cut, and no manual adjustment necessary for the lift chain to lift frame. The speedcast plows were 2 seperate pieces of chain- one lift and one carry. The lift chain had to be put in a chain hook on the lift frame and therefore was adjustable for blade lift height. Load on the chains is well under the working limit of the single run of that chain.

    The carry chain is designed to take the load OFF the lift cylinder- you guys ever read the book that came with your plows?? You put the weight of the blade on the carry chain alone (put it in float)- the blade will actually bounce less in responce to pot holes and such this way.

    If you're plow sinks down you have worn seals either in the lift cylinder, the valve block, or if you have a pump-on-truck system (Speedcast) the pump itself. This is what the carry chain is supposed to help prevent.

    And yeah, I'm one of those who are too lazy to go out and put the carry chain on between each customer too :) I use it for longer hauls- most of the time, but not always on my MM system- my Chevy with the speedcast has worn valves (blade drifts down while driving) so the carry chain is necessary until I get around to replacing the valve body (after I do everything else it needs now)
     
  8. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Thanks for the info. Actually, I have read the manual many times over and have spent hours on the Fisher site looking up literature on various things, but nowhere did it clearly spell out the use of the carrying chain--hence my confusion. Not sure if this was factory or a mod by the previous owner, but the carrying chain is attached to the A-frame by a weld between the last link on the chain and the side of the A-frame. I'm no expert on welding strength but it just looks like the weak link, so to speak, in the system.

    I have been carrying the blade both ways in the years I have the plow, never really sure which was right. From now on I will use the carry chain and leave the load off the cylinder.

    So I take it my valve body is the cause of the slow fall of the blade? Where can you get a new one? Or can you rebuild one?
     
  9. oldmankent

    oldmankent PlowSite.com Addict
    Messages: 1,318

    Most likely the "carrying chain is used when the plow breaks down and you need to get it back up for transport. Jack the plow up use the chain to hold it because the cylinder can't get pressure and you can get home without plowing your way home.
     
  10. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Here's what I mean about the carrying chain and the passenger side of the lift chain being welded onto the A-frame:

    [​IMG]

    I guess this is factory? The lift chain link is worn at the top--I really wish there was a U-bolt here instead, like on the driver side, so I could move to a fresh link and/or replace the U-bolt. I guess I can always drill some holes and do that myself.
     
  11. Flipper

    Flipper PlowSite.com Addict
    from CT
    Messages: 1,180

    That's a pretty old a-frame. Fisher stopped welding chains on the mid 80s.

    Just grind it off and drill for u-bolts.
     
  12. freakshow

    freakshow Junior Member
    Messages: 5

    yeah, that's pretty worn. I went to the hardware store and got some u bolts and new chain for mine. Pretty cheap and way stronger.
     
  13. justme-

    justme- 2000 Club Member
    Messages: 2,138

    Agreed- that is original and worn... and a nice old example of an 80's fisher!
    Gotta check my MM1, pretty sure the manual states about use of the carry chain- I'll try to get out to my dump and pull the book for the Speedcast too.

    Valves are usually rebuild able... if you can find the parts to do so and if the bores themselves are not too worn. Usually you're better off replacing the whole thing- Northern Tool used to list a valve body suitable for plows.
     
  14. streetsurfin'

    streetsurfin' Senior Member
    Messages: 770

    I didn't see speedcast system listed but I imagine the chain acts on the same principle. This is the only place I see mention of the carry chain in the manual for a MM1 w/solenoid electric pack....the mounting and removal procedure. I think it is there to prevent the plow headgear and frame from hitting the truck while pushing into it with the truck (see step seven in the mounting section). It seems to keep the two components locked in proper relation to each other for correct hook up alignment, as tension is on the chain when plow is removed from vehicle. I know that when you don't put the slack back in after mounting (did it by mistake), the plow will not drop all the way into a gulley or low spot when crossing over it, so I suppose it could be used for emergency transport in the event of a lift problem. This is from an on line manual and is also what is stated on the plow decal, back of blade.

    MOUNTING THE SNOWPLOW
    NOTE: The blade must be in the straight position
    when mounting or removing the snowplow.
    1. Drive vehicle forward fully engaging pushplates
    into attachment arms.
    2. Twist connecting pin to release tension.
    3. Remove electrical covers on vehicle.
    4. Attach electrical connector to corresponding
    connector on vehicle.
    5. Repeat steps 2-4 on passenger side of vehicle.
    6. Release carrying chain and reattach it leaving
    plenty of slack.

    7. Push headgear upward toward vehicle until
    connecting pins snap in place.
    8 . Pull jack lever outward and raise the jack stand.
    NOTE: Adequate chain slack is necessary for
    connecting pin/hole alignment.


    REMOVING SNOWPLOW
    1. Position blade parallel to front of vehicle before
    removing.
    2. Place solenoid joystick control in "Lower/Float".
    3. Push lift arm down.
    4. Pull jack lever outward. Jack stand will adjust to
    proper height.
    5. Disconnect electrical connector and reinsert in
    protective cover.
    6. Insert release rod under jack collar.
    7. Push down on release rod as you pull and twist
    connecting pin.
    8. Repeat steps 5-7 on passenger side of vehicle.
    9. Remove slack from carrying chain and reattach.
    10. Back vehicle away from plow.
     
    Last edited: Jan 28, 2008
  15. Tommy10plows

    Tommy10plows Senior Member
    Messages: 345

    Geez, emergency welding on a carry chain. I carried a longer chain and a hardened bolt in case of failure. All I do is wrap the chain around the plow a-frame and through bolt it, and I am done till I find a welder to repair it.
     
  16. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Thanks for the replies, all. I have a spare u-bolt that I will install on the passenger side of the a-frame for the lift chain, and will get another bolt for the carry chain. Probably should get a second one just to have as a spare on board the truck.

    Interesting that Fisher engineered the A-frame with the welded chain--how long were they made that way?
     
  17. Flipper

    Flipper PlowSite.com Addict
    from CT
    Messages: 1,180

    Until the mid to late 80's.

    I would replace the chain with one length Run it from the drivers side up over the hook down to the U-bolt, then up to the carrying hook. This way you can adjust chain length if needed. This is what Fisher did on late conventional and MM1 plows.
     
  18. justme-

    justme- 2000 Club Member
    Messages: 2,138

    streetsurfin- the Speedcast was the lingo (brand?) for the conventional plows before the MM system. It's so old I doubt there will be much online for operation or service info- we're talking pre-1990's.

    The points in the directions referring to the carry chain in hookup I believe have been left off from the 2nd generation MM1 and up- they originally though there was a possibility for the headgear to strike the truck on disconnection, but it can't actually happen- never could. That step was (I believe) left off the sticker in the 2nd gen MM1, and after almost 10 years with a MM1 I can state is makes no difference in the behavior of the headgear on disconnect, however it can make for a difficult reconnection as the carry chain being short prevents you from rocking the headgear back toward the truck, so once the snow has melted under the blade and the blade has settled (of sunk in the mud if you park on dirt) the carry chain is preventing you from pushing the headgear back far enough to engage the locking pins.