What the Cr*p! cracking frames when plowing?

[great white]

Apparently, there's a bit of a row over on plowsite.com about 88-08 frames cracking at the IFS mounts:

http://www.plowsite.com/showthread.php?t=81052

One gent has a heck of a horror story pic posted:

As the story goes, the loading on the frame is concentrated around the upper A arms mounts and stresses the frame to the point of cracking.

The fix is apparently a couple gussets on the frame a arm brackets.

This is the first I've heard of this. Anyone else?

:skep:

 

[bison]

I've seen a few that broke the front axle mounts clean off the frame in the engine bay,but i can imagine a snow plow constantly dancing on the front of a truck could flex the frame to the point of fatique without some frame strenghtening.
These trucks are not realy build to carry a plow.

 

[great white]

This is reportedly the fix over at the plowsite.com:

 

[3500GMC]

What a mess. A plow rig gets used up for sure.

on edit... Look at the *snubber* in pic #1... Somebody REALLY needs slapped.... :rolleyes5: I think they were using the cob job as a 'crutch' to hold up the weight of the plow.

 

[ak diesel driver]

I believe that's a Timbren weight carrier. I don't see how those gussets reinforce it anyway but side to side,

 

[88gmctruck]

You say 88-08? I could see the older GMT400's having the problem with age/fatigue, but not the newer stuff as much.

 

[great white]

You say 88-08? I could see the older GMT400's having the problem with age/fatigue, but not the newer stuff as much.

Yup.

There's a guy over there with a newer 3500 and the upper brackets are nearly cracked completely off.

Cracks from the welds extend into the frame rails. Guy is trying to get gm to warranty it, but is getting stone walled.

From what i've read over there, a couple years around 2000 came with a gusset on the upper rear from the factory.

 

[SnowDrift]

I believe that's a Timbren weight carrier. I don't see how those gussets reinforce it anyway but side to side,

I was thinking the same thing. It seems like it would help with lateral support, but at a glance, it seems the right way to fix this would be to strap the top and bottom of the frame. It would require plenty of pre-heat to both materials. The frame is thin since it is boxed and I'm guessing the straps will typically be pretty heavy, however, I don't think I'd put anything on it larger than 7 ga. (.1793) because anything larger than that would be overkill. If the weld is done right and the material placed correctly on top and bottom, it would be much stronger than the original design for that area.

 

[DieselSlug]

What a mess. A plow rig gets used up for sure.

on edit... Look at the *snubber* in pic #1... Somebody REALLY needs slapped.... :rolleyes5: I think they were using the cob job as a 'crutch' to hold up the weight of the plow.

I have the same thing on my rig. Its a Timbren kit like said earlier. The truck squats about 1'' less with the Timbrens installed.

My truck is a plower also, but i dont stack like the other guys do. I think thats what leads to this cracking is stacking snow. Puts a lot of stress downward on the front end.

I actually found a rot hole on the inner pass side of my boxed frame yesturday! Right infront of the idler arm bracket.. Not good.

 

[great white]

I have the same thing on my rig. Its a Timbren kit like said earlier. The truck squats about 1'' less with the Timbrens installed.

My truck is a plower also, but i dont stack like the other guys do. I think thats what leads to this cracking is stacking snow. Puts a lot of stress downward on the front end.

I actually found a rot hole on the inner pass side of my boxed frame yesturday! Right infront of the idler arm bracket.. Not good.

That's what I thought too, but the plowsite.com thread specifies stacking is not the issue:

How high do you stack snow? What is in the bed while plowing?

Stacking doesn't cause this problem.

Then what does?

Very simple--it's the pendulum effect.The truck is constantly flexing during plowing,the frame is obviously it's backbone,if there's a weak spot along it's spine,something will give.That weak spot is by the upper control arm as we all know.So to be proactive you need to weld in the gussets.

To elaborate on Tuney's comments further...

When you lift the blade, you cause the frame to arch. The front control arms are the pivot point, and the sharp bend in the frame creates a stress riser. And that's where the cracks start. And because the plow is pulling the front of the frame down, the control arms are the pivot point, that's why the crack opens when you lift the plow. And when guys run heavy counterweight well aft of the rear axle, the arching effect is amplified. There are cases where the frame has cracked/broken right behind the cab from the arching effect.

Fortunately, the flaw in the GM frame at the control arm brackets is well documented and easily remedied.

Another pic of an 07 3500 from the thread:

 

[great white]

That last pic shows you how the gussets could help.

If you think about how the frame is being loaded that is....

 

[Pruittx2]

Glad I got a snoway,, less that 600Lbs,, and I don't plow a ton,,, but when I'm done, I take it off, till the next event.

 

[great white]

I side skirted the whole issue by modifying my minute mount brackets with under bar supports from and older fisher mount:

carries the weight back past the weak spot in the arch....

 

[HighSierra86]

Ive had 89', 95', and an 01' with snow plows. Never had an issue other than the front end sags from the weight. There are TONS of these trucks running around with plows and ive never heard of a frame issue until you posted this. Maybe its dependent on how many miles are put on plowing or your driving habits with the plow.

I wouldnt be too concerned with it if all you are plowing is a few driveways. My 95 had both the weight of the diesel and a fisher mm...all on a 1500 frame. 230K plowing miles, and no cracks!

 

[NVW]

It's probably the same as with the 6.5. you only hear of the bad.

The gussets would help distribute the stress farther out, (stress from the weight of the plow). The apex would be at or behind the wheel. A fish plate would be better in my opinion but not as easy.

I see similar stress with bale decks on trucks, they break the frame behind the cab at the front deck mount. Welded a few frames up in that area.

 

[3500GMC]

Boy that crack in the first photo post #1 is way too close to those 'Timbrens' that were talked about.. The frames were made to load at the tortion x-member... Not up front there at the BUMP STOPS..

 

[DieselSlug]

That's what I thought too, but the plowsite.com thread specifies stacking is not the issue:













Another pic of an 07 3500 from the thread:

I have to think otherwise on the stacking. There is a tremendously larger amount of weight on the front of the truck when stacking. It still acts as a pendulum, but more so with that much more weight acting on the front of a truck, basically a multiplying factor. I really think something other than regular plowing happened to that first picture.Or the frame is a lemon. I think many believe that stacking isnt the cause of this because so many people do it without realizing it and nothing ever happens to their truck. Ive seen some cracked frames on f-150's, and one on a 95' K1500, that was at 250K, however it was a small crack back by there the torsion bar crossmember was.

 

[3500GMC]

Ok I give.. WTF is 'stacking'?

English?

 

[DieselSlug]

Ok I give.. WTF is 'stacking'?

English?

It when you pile snow up like a bucket loader, yet your using a pickup truck. As you are reaching a pile of snow at the end of a run you lift up the blade in an attempt to stack the new snow on top of an already made pile. So lifting the plow up while at the same time pushing into a pile sort of creating a bucket infront of your blade to lift snow with, and puts a lot of stress on the truck and plow system. The pendulum of the truck is happening where the cracks are. Due to the weight of the plow, snow, and engine (where the motor mounts are attatched) on the front the frame the cracking seems to happen right behind it. Also if your not careful in doing this snow can get behind your blade easily and get you stuck quick!

 

[ak diesel driver]

around here we don't have to lift our blades to stack the blade will ride up on it's own. We usually have pretty dry snow tho