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compressing trip springs during blade reassembly

Discussion in 'Truck & Equipment Repair' started by Megunticook, Dec 7, 2007.

  1. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Sorry if I'm the ___th idiot to ask the same question (feel free to just point me to a previous thread, although I didn't see one):

    What's the drill with the trip springs when reattaching the base angle to the blade? Do you need something to keep them compressed while you install them?

    I have an old Fisher with three trip springs (diagram posted below)--any advice from somebody who's done this before would be much appreciated. Thanks.

  2. theplowmeister

    theplowmeister 2000 Club Member
    from MA
    Messages: 2,511

    Before I took mine apart I pushed the plow against a telephone pole to push the trip edge, a Friend then stuck a grade 8 1/4 X 3 bolt in the hole of the spring center plate to hold the spring partially compressed.

  3. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    There was a post about your very problem last season.
  4. Rowski

    Rowski Senior Member
    Messages: 129

    Here's what I've done

    Stand the plow up, mounting ears straight up. Take a long pipe or pry bar and in the shoe mount bracket. Just lift up on the pipe to compress spring. Insert a bolt. As for installing them. I use out hydraulic press. Compress the spring past the top hole a very short bolt. Install spring on plow. Use pipe again to "trip" spring. After fully compressing the spring (on the plow) remove the short bolt installed during initial spring compression.

    That's the way I was taught from my father who's been doing it since the early '70s.

    I'm sure there are other ways, especially if you have the tool.

  5. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    You mean use a very short bolt here? Not sure I follow--doesn't it need to be longer than the diameter of the spring so it holds the spring in compression?

    There will be a good deal of tension on that bolt at this point, right? Won't it be sandwiched between the top of the spring and the top anchor (the part of the blade with the slot in it is what I mean)? And I presume you have to tap it out with a hammer and punch? And when you do, the spring bar will slam through the slot, right?

    Why do you need to fully compress the spring during this part? If it isn't fully compressed, it won't fit beneath the top anchor?

    Don't have a hydraulic press but I guess I can figure something out for that part.

    Thanks a lot for the tips.

    That's the way I was taught from my father who's been doing it since the early '70s.

    I'm sure there are other ways, especially if you have the tool.

  6. Lawnscape89

    Lawnscape89 Senior Member
    Messages: 213

    I have had the same problem and here's a link to my post


    Once you put the bolts in the holes, there is NO pressure on the trip edge...I assure you, the trip edge just swings (which is what I had to replace). It's really quite simple, but please be careful and use strong enough bolts. The tool that Western has actually uses cut pieces of 1/8th inch rod, but a strong bolt will do just fine.
  7. BJH Snow

    BJH Snow Senior Member
    Messages: 142

    I also have a Fisher Plow (conventional) and I replaced my springs last year. I didn't have the tool to compress the springs and came up with my own solution. On my Fisher the top plates don't have the slot to let the rivited bolt (on the top of the spring bar) through so I grinded them off and punched the rivit out of the hole. I purchased grade 8 bolts that I would slide in and bolt them on. I slid the sping and spring bar in from the bottom with the blade all the way in the air. I then took my 3 ton car jack and got it to sit under the spring and bar and compressed my springs with the jack. Once I got it through to get the bolt on (at the top of the spring through the top plate) I bolted it up and then released the jack and the spring was set in. To get the bolt connect on the trip bar, I lowered the blade slightly off the ground to get my jack under it and manouvered the trip blade up and down until I could get the lower bolts it. It worked for me and I didn't have to get the tool.

    I tried some other methods with bolts and webbing from tie down straps and it was a little dangerous and almost lost a finger when one of the straps let loose while trying to compress the spring with the bolts.
  8. Megunticook

    Megunticook Senior Member
    from Maine
    Messages: 190

    Appreciate the help, everyone. I tried an interesting technique suggested by a Fisher rep. I spoke with on the phone (very helpful guy, by the way).

    This is apparently the old school homeowner's way of doing it--I added a few things of my own devise:

    1. clamp the base of the spring bar in a vice
    2. grease up the bottom of the spring and place it on the bar
    3. insert a 1/4 x 5" grade 8 capscrew through the spring, through the hole in the bar, and out the other side of the spring
    4. grease the top and bottom of the coils from the point where the screw is on up to the top of the spring
    5. rotate the spring counter clockwise so that the screw travels "up" the coils, compressing the spring in the process; toward the end this will get quite hard and scrape paint off the spring, but the grease helps
    6. install, then remove the capscrew

    Worked pretty well, although on the first one I discovered that the factory-drilled hole in the bar is not far enough down to compress the spring sufficiently, so I had to drill a second hole an inch lower. Not sure what the engineers at Fisher were thinking on that one...

    Feels good to finally have that out of the way!