Cat 428C - Broken Sideshift Frame

[allenr]

Had another breakdown last night.

Apart from the occasional blown hose (usually caused by damage) I had the bottom slew pin break a few months ago.
Thought the new one had broken last night but it turned out to be the 1" thick plate which mounts the bottom slew bush.

I had noticed a long time ago that the plate had a slight bend near the bush but obviously it must have been flexing there all the time to fatigue and break as it did.

Ground out the crack to 5-7mm to allow weld.
Ideally would have removed the frame to allow better welding but would have had to undo all hoe hoses.

Top weld done

Prior to grinding and welding bottom

1"x4" plate added above the original plate, cut away to allow welding around slew bush. Two 2"x1" flats on edge added below the original plate.

Hopefully all the stengthening will result in it being stronger than original. The flats on edge below will reduce the already lacking departure angle. Probably shouldn't have joined the two flats with a thinner cross piece as that could drag dirt into the pivot bush between the flats.

After a primer and top coat. The Cat yellow is as old as the backhoe and has had jelly strained out and is no longer as glossy as it was.

 

[Arkaybee]

ATTA BOY! ! Now we're talking STRONG. That is just what I would have done.

Arkaybee

 

[Kernopelli]

Good job on the fix. I am a little surprised when looking at the pictures. I've got a 18"x36" piece of 1" plate in the garage and when you pick it up it's hard for me to imagine anything I would ever build that would need something that thick, it is a formidable chunk of metal. The pics make it look too thin for the 428's application. I'll bet this isn't the first time this has happened.

 

[allenr]

Thanks for the encouraging words, guys.

I'm a little annoyed that I didn't see it fatiguing - for instance while greasing.

However there usually is a layer of dirt on the plate and so long as I can get to the grease nipples it stays there. I try to avoid reversing in rough loose soil - it can get right up among many of the greasy pivots.

I guess the strengthening required would still have been much the same.

 

[kebo]

Great job on the fix. Now you'll find out what the next weakest link is!!!

 

[GeneD14]

Nice job on the fix. It's good that you found it before it came totally apart and tore or twisted something else up.

 

[allenr]

Nice job on the fix. It's good that you found it before it came totally apart and tore or twisted something else up.

While there was a bit (about 1") together on one side there was no chance of not noticing - it sounded like a gunshot when it came apart.

Louder than when the pin went.