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Pelican 02-21-2010 03:39 PM

Stop Nuts Problem
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A couple storms ago, I noticed what appeared to be cracked welds in the nose of my A-frame on my 810. There was snow on the way so immediate repair was not possible, I decided to run the plow and monitor the cracks. Well, with that event I had to do my full route and afterward I needed to make some other repairs and checked on the cracks. To my horror, they had opened up to about 1/8" and were much more significant than they originally appeared.

Here is what I saw when I checked on the cracks. Note the indentation on the pivot frame of the stop nut, and the swaging of the stop nut itself. If you look closely, I outlined the areas mentioned, for some reason it didn't transfer well.
Attachment 24741

Side view of A-frame
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Pelican 02-21-2010 03:44 PM

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After disassembley, I found the cracking to be severe, the nose of the A-frame had actually been stretched away from the rest of the assembly.
Attachment 24743

If you look closely at this picture, you will see the cracks extend to the hoist cylinder pin and that there actually a piece of metal missing there.
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Attachment 24745

Pelican 02-21-2010 03:49 PM

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After removing the A-frame, I discovered even further damage, the rails underneath the assembly have cracked almost the entire length

Attachment 24746

Attachment 24747

And these are the grade 8 bolts in place of the cylinder pins....bent.
Attachment 24748

Pelican 02-21-2010 04:13 PM

After studying the carnage of my A-frame, I'm convinced that the addition of the stop nuts created a new fulcrum point that allowed undue energy to be transferred to the nose of the A-frame which it was not designed to absorb. As a result, the metal fatigued, eventually tore and stretched to what we see here. I also still have bent pins, which were the reason for the stop nuts to be installed.

In hindsight, I don't think I'd do this modification to the plow. I've still got bent pins, and now an A-frame in extreme disrepair. Anyone who has this modification on their plow will want to monitor the A-frame closely.

T-Zab 02-21-2010 05:00 PM

Steve, what size/weight truck you got behind that plow ?

I didnt notice any wear in your welds were they hit the nuts, mine need to be touched up with the welder a time or 2 per season. Seems odd the frame and bolts took a beating like that and the welds look so clean.

jmac5058 02-21-2010 05:09 PM

Its a goog thing you reguarly inspect your equiptment looks like a major disaster was avoided.Is the fix just a fue well placed beads or is total refabbing ness.

The boys 02-21-2010 05:56 PM

Ill be interested to see what jerre has to say about this. I know if your center bolt gets loose it will allow enuff movement to cause bent pins and even jerk the guts out of a cylinder. And I had to add a little more to welds on the quad to combat part of the problem, but Im not jumping to conclutions till I get Jerres two cents on this one.

JD Dave 02-21-2010 06:00 PM

I can see from a leverage standpoint how those nuts can cause a lot of stress. On some of our larger blades we have made stops out of 2x2 tubing but we place them closer to the cylinders.

Pelican 02-21-2010 06:09 PM

The plow is on my '01 F-350 SRW. The truck weighs 7600, plow is just over 1000 and I have a 1000lb concrete block strapped on the back. I don't beat the truck up by any means. The center bolt seems pretty snug, I've had one go sloppy on me in the past and this wasn't bad at all.

jmac, you're right. If I hadn't caught this catastrophic failure would have been the result and I probably would have snapped the cylinders too. Fortunately I have a well equipped fab shop nearby, the plan is to replace the whole center beam on the A-frame.

T-Zab 02-21-2010 06:29 PM

[QUOTE=Pelican;264556]The plow is on my '01 F-350 SRW. The truck weighs 7600, plow is just over 1000 and I have a 1000lb concrete block strapped on the back. I don't beat the truck up by any means. The center bolt seems pretty snug, I've had one go sloppy on me in the past and this wasn't bad at all.

Just wondering on the weight Steve. My truck goes out alot heavier then that every storm. Something to watch for sure. What year is the plow ?

John DiMartino 02-21-2010 07:48 PM

Steve, you are very lucky to catch that problem,you could have tore the plow right off the truck...
On the plow truck weight ,I run the same plow ,same year model 810,but my truck weights about 2-3000 more typically.Upon you telling me what happened I immediately inspected my a frame,and found it to be in perfect condition.I do not have the nuts welded to my plow,I have bent 4 pins in 5 years of use so far. I think the pictures clearly show the problem..I would be interested to hear what the repair facility thought caused the damage.

Pelican 02-21-2010 08:51 PM

Todd, the plow is an '03 model, the nuts were put on I think 2 seasons ago.

Chuck Smith 02-21-2010 09:44 PM

Looking at the very first pic, I would guess the plow is angled right alot more than left. Not that it makes a difference, it is still cracked, but something has to give, nuts or no nuts. The area where it cracked is taking the most stress, nuts or no nuts. The A Frame seems to be the weakest part of all plows. I will never forget the Dodge when I worked for Uncle Sam that had the plow at full right angle and clipped a catch basin. The plow mount took the hit, but it bent the truck frame nicely. Couldn't even open the passenger door. They totalled it. Better a cracked A Frame that a bent truck frame.

On Edit: The center pivot is not really the fulcrum, the fact that the nuts are there, and the bolts still bent kinds proves that. The end of the angle ram is the pivot. Think of that center pivot with the nuts like a set of long bolt cutters. It smeared the nut, and wore the other part, and the angle ram bolts bent, proving the nuts are not acting as stops anymore. There are no nuts on a Meyer, and I know 4 or 5 good shots on the tip of the plow I can rip apart a center pivot. Same with a Western straight blade, ask Fred or Chris how many they have repaired. That combined wear on the nut and the sector (or whatever Blizzard calls it) of 3/8" or so, translates into a lot more 5' out at the wing tip. The wing tip is the lever, the angle ram end the pivot, and the center bolt is tearing out.


Pickering Snow 02-22-2010 01:58 AM


Although good pics to study by it looks like the stop nuts are back to far after two seasons my stop nuts would show contact wear which yours dont, this would also account for the bent pins.

Honeslty it looks like the problem started on the nose bushing pivot and the slop there the cracks spread off that just my opinion. My stops were closer again then your picture and after two seasons usally the sides of the nuts were wore off from contact. Again good pictures but looking it just appears the stop nuts were back to far to even come into play. Either way you have some welding to do .:wink

snowjoker 02-22-2010 04:11 AM

Are you plowing roads with this blade Steve ? It seems to me that the vibrations are causing the welds to crack and all hell breaks lose once that happens.. No matter how good the welds are they will not hold up to the constant vibrations. Like constant road plowing.. Glad you caught the problem and its something we all can keep an eye on !

Jerre Heyer 02-22-2010 04:30 AM

Steve, good catch on the crack on the nose of the A frame. Tom and I just did a couple of older and newer 810's and 8611's that had torn the bushing completely out of the center of the A frame. These plows were stock with no stop nuts / plates on the A frame. They had torn the center bolt bushing out to the point that there was over 1/4 " all around the bushing of crushed aframe pocket.

Yes the nuts or plates do increase the point loading on the nose of the A frame but we've seen them torn out this way even without stops on the plows. I'm sure the guys at the weld shop are good. Have them look at using full 1/4" matl for the new center piece of the A frame and double plating the nose area on the inside. Pay close attention to the center to center distance for the nose bushing though as you will see cyl damage if it's too long.

Your cracks in the rear by the cross beam are not a real common thing but we've seen it on plows that are doing a lot of road work. Had a couple that tore completely off the cross tubing on the bottom. Have them check you mounting ears closely too as they can tear off the back side.


GMC Driver 02-22-2010 05:42 AM

What about adding the nuts to the bottom J - would that have helped in this case?

The only problem we've seen is on the 8611 that plows roads - we built up the stops and the quadrant in an effort to eliminate the cylinder problems we were experiencing. We lost a little bit of angle - but not enough to make a difference. Just wondering if the nut placement, combined with wear might have been the contributing factor - I know it was for us.

Glad to see you caught it in time Steve.

wyldman 02-22-2010 09:59 AM

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I've seen a few of the Blizzards do that. Bracing the a-frame will help,as well as ensuring they are completely welded with good penetration. I've seen a few with very poor welding.

Here's the stops we use. We have had no issues with a-frames cracking,or pivot beams bending and denting. The nuts eventually bent or dent the pivot beam enough they are no longer effective, and then the pins bend.

John DiMartino 02-22-2010 03:00 PM

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Today,when checking my truck for the approaching storm,I went over the A frame better than the quick look I gave it the other day.Upon inspection of the bottom,it is clear that mine is cracking too. It is clear that the weld quality on top isnt the best,but it isnt cracking there,it is cracking from the bottom up on both to follow. Thank you Steve for the heads up,on this issue.I dont know how long it would have made it,but I welded the cracks and factory flaws for now,being feb 22nd,Im going to try to finish the season,now I will check those spots after every storm.
I really cannot complain about it,its the 6th year of pushing on that blade,its been holding up great.A few 1/4" thick plates and all will be good again...
These first shots are the drivers side after a wire wheel cleanup.You can see the weld on top isnt the best,but it wasnt cracking there,although it appears it is,it is the weld.

John DiMartino 02-22-2010 03:10 PM

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Here are some more...first one is the drivers side bottom where its cracked. Second 2 are pass side,it was tearing away.I went underneath there is nothing broken under it as of yet...

John DiMartino 02-22-2010 03:13 PM

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sorry for the duplicate above,this is driver side bottom pic..

Mark Oomkes 02-22-2010 03:33 PM

I've got 7 with stops and haven't seen this. Had a couple that the bushing wore and caused lift height problems, but not cracking like that.

Even switched out some A-frames due to bending, and have been straightened.

Can't remember right now, but I think only a couple have not seen well over 300" of snow in the past 3 seasons. Over 60 this season.

I think Chuck's assessment is pretty close to dead on.

Chuck Smith 02-22-2010 04:54 PM

Johnny, your pics and problem bring up another "problem"... which happened first on Steve's? Did the welds crack on the bottom out of plain sight, and then the top tore, or did the top tear first? With multiple tears and broken welds it is often difficult to tell which happened first. Like you said, no nuts on your plow, so maybe the nuts don't have that much to do with the problem? Maybe they do? Maybe plowing mostly pavement vs. mostly gravel makes a difference?

This just brings to light that no plow is indestructable, and the center pivot is the weak point on *most* plows. I say that because I am sure I will be flamed by a person who owns <insert brand> that never had a center pivot problem. Bottom line, inspect your plows regularly, top and bottom, and everywhere in between. Welds fail, and steel tears next to welds.

Glad you caught yours before more damage was done. At least it wasn't too cold out to weld it up.


JohnnyU 02-22-2010 05:09 PM

Interesting... I'm hoping to get mine torn down in the next week or so to replace some hoses, bent pins and I will definitely check this out. These are by far the beefiest a-frames of any light-duty plow I've ever seen. It would have to take quite a bit of prolonged hard use to have cracked the welds and torn the tube like that. Either way, I'll agree, nothing is indestructible.

hlntoiz 02-22-2010 06:07 PM

IMO with any equipment no matter how tough, constant hard work and abuse will eventually cause problems. For example I have seen excavator buckets that are welded like crazy eventually break or tear. Just part of owning equipment. It needs to be checked regularly. 6 years of constant pounding will eventually make its mark. If after multiple years of use and it didn't ever break (like that) then you didn't use it to its full potential!:wink It is when things break like that after limited use then you have issues with quality.

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