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Question about unimount truckside frame 88-98 chevy

Discussion in 'Western Plows Discussion' started by bizzo15, Jan 30, 2011.

  1. bizzo15

    bizzo15 Senior Member
    Messages: 107

    I'm in the market for a plow for my '91 chevy 1/2 ton and I've pretty much decided I want to pick up a western unimount setup for it. There's plenty for sale in my area but I've yet to find any that are totally complete (truckside mount, wiring, and plow blade) for a decent price or that aren't junk. Since I'm probably going to end up having to piece together all the used parts from several different sources I have a few questions on the mounts. It looks like there are two different mounts for this style truck one that was made for the '88-94 trucks and one for the '88-98 trucks. Does it make any difference which one I get? Also once I get the correct truckside mount will any unimount plow bolt up? I'm looking for a 7.5' plow but don't want to pass up an 8' if I come across a good deal. Thanks in advance for any help. I'm a total newb to the stuff and want to make sure I'm well educated before I spend any $$$.
  2. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    Unimount is unimount as far as hooking up the plow goes, the electrical is the concern and that is where you are going to pay the big bucks. If you aren't a mechanic and are not real strong with electrical then you might as well go to a dealer from the get go. Every vehicle has a unique wiring system to make the headlamps switch between the truck and the plow. That is where the money gets spent. You could just rig it up with switches but that takes some skill too. The one thing you want to do is see the plow that you buy work before you take it. Troubleshooting an old plow takes a lot of time. If you know it worked before you bought it then at least you only have to deal with electrical.

    As far as mounts go you would be best to get one off the same model truck as you have so it bolts right over. Getting a mount for that from Western will be difficult. You can still buy them in pieces but you have to weld them together yourself. If you buy a used mount don't be fooled by someone who says it came off the same year truck. There are numerous differences between vehicles of the same year. Even now when you use quickmatch at the Western site for a new plow you will find there are three different kinds of K1500 besides the box length, engine size and cab type. You need to get a look at the right kind of mount for your truck and then make sure that what you buy is right. It might have been easier to buy a used truck with the plow mounted. Good luck!
  3. ABES

    ABES PlowSite.com Addict
    from MN
    Messages: 1,322

    ANY unimount from a 88-98(99-00 classic) will fit your truck. Western did make 2 kinds of unimount frames IIRC but they will still both fit your truck and work with any unimount plow. Every unimount plow made will fit any unimount frame electrical is different between straight blades and V's but thats it.

    Westerns website has the installation instructions to install both the mount and the wiring. The mount is the easy part the electrical inst too bad but can be difficult at first especially if using a used harness.
  4. bizzo15

    bizzo15 Senior Member
    Messages: 107

    Thanks for the reply. I'm alright when it comes to electrical and I'm pretty sure I can wire the plow no problem. From everything I've read the frames on the '88-'98 are the same from 1500 through 3500 and the 3500hd is a different frame. The only thing that confuses me is why western lists two mounts one for '88-'94 and one for '88-'98 unless they just improved the design of the mount itself. Like you said it might have been easier to just find a truck with the plow mounted but I've put a lot of work into my truck and really don't want to start from scratch on another truck. I guess the hunt continues
  5. bizzo15

    bizzo15 Senior Member
    Messages: 107

    Nice that's what I wanted to confirm. I think I"m going to grab the mount and electrical get that all installed and then look for a blade setup. This way I can't test the blade and make sure that it works even if they don't have it mounted to a truck.
  6. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    That sounds like a good plan, that way they can't ******** you about what works and what doesn't. One thing to check before you pay is the pivot point, the quadrant and the A frame. The old unimount V plows are pretty strong but the straight blades tend to wear out at the blade pivot. Lift the plow up off the ground, then try to push the blade up & down at the end and then in and out at the top. If that pivot bolt and the surrounding metal is worn like they usually are you will have to pay a welder to remove the blade and rebuild the pivot. When I do it I use between two and four hours. The quadrant is the D shaped piece of metal that moves with the blade, they often bend and they are not cheap! Have a good look before you pay.
  7. bizzo15

    bizzo15 Senior Member
    Messages: 107

    Thanks for the advice. I just checked out a unimount the other day and saw that it had a lot of play in it. Especially the part where the d shaped piece of metal rides on that c shaped channel that the chain lift attaches to. Is that normal? The guy of course tried play it off like it wasn't a big deal but of course he was trying to sell something. Then I inspected the pivot bolt itself which was lose. Between that and the crack in the truck side mount I knew this plow had seen a rough life and I was going to pass on it. I"m assuming some play on the plow is normal especially being that these unimounts are older plows but how can one tell how much is acceptable play? It almost seems worth it to buy a new plow but I really don't want to invest 5 grand in a new plow to hang on my 20 year old truck, especially since for the foreseeable future I won't be plowing for profit.
  8. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    The amount of play is subjective of course. If you get the chance to look at several plows you will get a feel for what is good and bad. It's really hard to convey in text just what is acceptable. Something to look for is the air gap at the back of the quadrant. The quadrant is the D shaped piece that moves with the plow. Right about where the chain connects to the A frame (goes from truck mount out to pivot point, moves up and down but not side to side) there is a chunk of metal in an upside down L shape that goes from the A fram up and over the quadrant. There is a hole in this piece of metal that matches up with three holes in the quadrant. You could put a pin through there an lock the blade in straight, right angle or left angle. If the pivot is badly worn this chunk of metal has to take the brunt of the load off the blade and quadrand so they tend to get bent up so that there becomes more and more clearance. A good pivot will not have bent that piece. Also you could take a magnetic angle finder and place it on the cutting edge. If the pivot is badly worn the cutting edge gets closer to straight up and down. The angle of the cutting edge is called the "atack angle". After looking at a few side by side the difference would be obvious. This can also indicate a bent quadrant but that is hard to see unless you dissasemble it. Have a look at his pdf file...


    Zoom in on the quadrants section and then look for the red and white number 32, 33 and 34. They all have those three holes I mentioned. Now look to the right and see the standard and pro plow three and four spring A frames numbered 64 , 65 and 66. If you look close you will see the part numbers 72 or 73. Just under that part number in the picture is that upside down L shaped quadrant retainer thing. The heavy weight number 67 has three of them. That is the thing that will be bent up so that there is an air gap between itself and the quadrant where those holes slide by. If you can fit your finger in between that retainer and the quadrant it is bent. If you could angle the blade to one extreme and then take a little light and look from the side at the tip of the A frame between the layers of metal you might be able to see if the tip of the top piece of the A frame is actually broken away and gone. That is pretty extreme but not uncommon.

    Have a look below at these two photos of a real bad one I just repaired. You can see in the second photo that a piece of the A frame top layer is actually missing. Incidentally this same plow was repaired by one of my coworkers just a year before, he doesn't work here any more.

    I hope this helps... :waving:


    Last edited: Jan 31, 2011
  9. bizzo15

    bizzo15 Senior Member
    Messages: 107

    wow thanks for all the help and detailed responses mishnick, you seem to know quite a bit about these western plows. That part you mention about the upside down L shaped peice that you can stick a pin in to lock the plow is where I noticed a significant amount of play on the one plow i went to check out. With the blade in the air could rock the plow up and down a couple of inches due to the play in that area, which based on what you've said definitely tells me the pivot area was worn out. Is there a way to stop the pivot area from wearing out or is it just one of those things that happens over time due to wear? Also typically if you find a plow that has a worn pivot area and needs rebuilding is it even worth it? I mean how much does a repair job like that cost?
  10. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    These model of plows have no swivel plates at the rear end like the newer ultramounts so they were deliberatly designed to "flex" at the pivot point making them inherantly weak. Every winter our shop rebuilds several of these. People usually say "we just want to get through one more season" but after the repair they end up keeping them for another fifteen years...

    Remove the blade from the quadrant by pulling the springs, the shock and the blade trip bolts. With the blade and rams removed you should be able to move the quadrant on the A frame and see just how loose it it. Remove the quadrant and examine the hole, if the top plate is broken away you may have to cut the damaged metal away and reweld a plate back in so you have metal to redrill and weld to. The bottom layer is angle iron and it is always intacts.

    I like to use two pieces of 1/4 inch wall steel pipe with 3/4 inch inside diameter (to fit a 3/4 bolt). Put the quadrant back on and put a pin in at the L bracket to ensure the quadrant is in the right place. Drill the new or repaired top plate to allow one of the pipe pieces to fit in. Put a bolt through the quadrant, the A frame and the two pices of pipe. Now weld the pipes to the A frame and quadrand. I like to us stick welds but a mig would do it that's all you have, you just wont get the penetration or the strength of stick.

    Give it time to cool, throw a shot of primer and paint on it. Use lots of antisieze compound after it cools to reasemble with a new grade 8 bolt and locknut. Then reassemble the blade, springs and shock. See bad photos below. Good as new! When I do this it takes between two and four hours depending on how bad it is worn.



  11. twinman326

    twinman326 PlowSite.com Addict
    Messages: 1,683


    why did you put a blot through the frame? (last pic)
  12. mishnick

    mishnick 2000 Club Member
    Messages: 2,243

    First the bolt is used to align all the pieces while welding and then it holds the quadrant and blade on!! You have to take a bolt out of the same spot when you pull it apart. This is the pivot bolt, the original is about 2 1/2 inches but the one shown is about 5 inches to accomadate the two pieces of pipe that are welded in for reinforcement.