stress cracks in structure

north country dozer · Post by **north country dozer** » Tue Apr 07, 2015 12:17 pm

Gentlemen, I have widening stress cracks in the u-shaped arm that lifts blade up and down on my 1981 450 c dozer. Got real bad after this winter. My question is this: can I just weld a bead over the crack to seal it back off and strengthen it??? Thanks in advance

NickMartin · Post by **NickMartin** » Tue Apr 07, 2015 1:53 pm

Never just weld a crack. It will open back up eventually. I always drill the end of the crack at both ends with a drill about twice the diameter of the crack width. This helps to put a stop to the crack further developing.
I would then weld up the crack and fill the drilled holes. For even better results, I would then grind down the weld and plate over it. Wouldn't make for much of a show piece but it sounds like you, like myself, are after a solid working piece of equipment.
Just the way I would go about the repair. Others may have more advice.

Paul Buhler · Post by **Paul Buhler** » Tue Apr 07, 2015 5:26 pm

Some of the hard working inside six way blade frames had a habit of cracking when I was using them. We would true them up, on or off the machine depending where the crack was located, chamfer the crack, weld it up, grind it level and like Nick said, plate over it with a nice looking piece so it wouldn't crack in that area again. Good luck.

north country dozer · Post by **north country dozer** » Wed Apr 08, 2015 5:26 am

thanks guys. as always piece of plate steel wool help strengthen anything. Unfortunately though the piston thAt angles the blade from left to write sets just above the frame in which the crack it's on. the crack is all the way on the top corner but it would have to be a pretty thin plate of steel to make it under the piston.most likely 1/8". But I guess something better than nothing

north country dozer · Post by **north country dozer** » Wed Apr 08, 2015 9:17 am

Has anyone ever heard of the u frame for the blade breaking off entirely??? I have some trees that I need to skid out for milling and am skeptical of pulling with the front blade. Part of me says I'm still OK but would hate to break or compromise entirely

Post by **Lavoy** » Wed Apr 08, 2015 3:11 pm

If possible, use the drawbar, but if you have to pull with the blade, make sure the chain is hooked to the main c-frame, not the moldboard or angle components. Also, if you have reverse in the transmission, I would use reverse not reverser depending on the load, but that is just me.
Lavoy

Paul Buhler · Post by **Paul Buhler** » Wed Apr 08, 2015 3:16 pm

Blades are designed for mostly pushing and some back dragging. When you use them on a regular basis to arch logs, the uneven load often causes torqueing and strains the frame. In your case the frame is already compromised, so you decide. At the very least the crack may grow and the frame be bent further which will be that much harder to fix. JMHO Paul

north country dozer · Post by **north country dozer** » Wed May 20, 2015 7:49 pm

Thanks guys for your replies. I had her welded up for some barter work and logs are at the mill being cut. Love this forum.

Lavoy, I'm unsure of reverse vs. Reverser... Its an '81 450c... I'm not familiar with a reverser

Post by **Lavoy** » Thu May 21, 2015 8:13 am

Then you are fine, your reverse is in your HLR lever, you have no reverse position on the range shifter.
Lavoy

Stan Disbrow · Post by **Stan Disbrow** » Thu May 21, 2015 10:14 am

Hi,

You will read where many of us have reversers. The older machines, and the JD350, had regular gear transmissions. So, they had a reverse gear. Some machines have a reverser unit that causes the input shaft of the gearbox to spin backwards. So, when engaging the reverser, the forward gears all become reverse.

The JD450 has a Hi Lo Reverse transmission, so there is no separate reverser in between the engine and the transmission. So, you need not be worried by all the reverser related chatter you see.

Stan

Tigerhaze · Post by **Tigerhaze** » Thu May 21, 2015 12:09 pm

To Stan's point, the other difference with the HLR is that it is a powershift transmission so you don't have to be concerned about the discussions regarding coming to a stop and clutching to shift in reverse like with the earlier gear reversers in the 2 cylinder models. I didn't understand that when I first joined the board so good to repeat that again.

Stan Disbrow · Post by **Stan Disbrow** » Thu May 21, 2015 1:43 pm

Hi,

I think that, perhaps, by the time they were designing the 450, someone figured out it was way too easy for an operator to lunch a reverser - and so decided to make the HLR powershift!

For a while there, I had a modern 4500 wheel tractor with a 12x12 powershift reverser. Every so often someone would ask me why I was using the clutch and stopping dead, and then shifting. I would say 'so I don't screw up my 420', and that always got me a befuddled look....

Stan

north country dozer · Post by **north country dozer** » Wed May 27, 2015 12:07 pm

Thanks for the replies guys. I think I understand, but just for the record, I have my shifter to the left of me and it has R,N,H,and L. And I do have to clutch and come to stop to reverse.

Paul caught my eye with his comment regarding the blade capabilities. Should I not be chaining and dragging my logs with the front blade? Thanks in advance

jtrichard · Post by **jtrichard** » Wed May 27, 2015 12:42 pm

[quote=" has R,N,H,and L. And I do have to clutch and come to stop to reverse.
(SHORT ANSWER NO you do NOT have to clutch or stop to shift)
"Paul caught my eye with his comment regarding the blade capabilities. Should I not be chaining and dragging my logs with the front blade? Thanks in advance[/quote] AS for pulling logs with the blade i see no problem pulling them with a 450C UNLESS they are GIANT SEQUOIAS

Paul Buhler · Post by **Paul Buhler** » Wed May 27, 2015 4:56 pm

i see no problem pulling them with a 450C UNLESS they are GIANT SEQUOIAS

I agree. I welded hooks on my blades for the times when using the blade to get/move a log or tree made sense. But, I didn't make a habit of using the blade as a log arch - too much leverage on the various components resulting in blade frame cracks, etc. besides, I didn't like driving in reverse for long distances.

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stress cracks in structure

stress cracks in structure

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