Possible broken drive axle D grader

I think we've all done that, (or similar) a time or two over the years. Good you caught it now rather than finding it under a bench remembering, "I remember dropping that" and never retrieving prior to the next task and then forgetting all about it.....

I imagine that many D grader owners have chain box story's. When I got my grader one of the chains for the left side was sitting on the floor of the cab. Using a magnet on a telescopic handle I started looking in the chain box for the pin for the master link. Besides some pieces of metal I fished out a very badly beaten up 1/2" drive 5/8" socket. It was just large enough to jamb the driven sprocket. I removed all the oil and cleaned out any metal pieces and reassembled the chain. The old chain was stretched enough that it would jump a tooth now and then so I finally bought a new chain.

Yup, I have welded bearing races to shrink them, if you get it right they just fall out

Those SPOTS where the bearing sets actually look like caused by an arc welder ?  Im wondering if they could not get the race out and welded on it to shrink it... Dont know how they got that deep, but look like local hot spots / points from a weld stick..

Edited by steve(ill) - 25 Jan 2024 at 8:22am

Edited by LangdonStevenson - 25 Jan 2024 at 1:53am

Good on ya mate! Hopefully she goes smooth on reassembly. 

Also the axle is 65 years old.. Could have been made to spec and just hit something HARD and put a small crack in the shaft that grew over time.... YES, each shaft has a weak point and that would normally be at a sharp cut step in the shaft. ... or could be a small radius cut in the shaft........hard to tell what happened in the last 60- 75 years..

Les Kerf - yes, that's a valid point about manufacturing not following the design documents. It just goes to show that product quality is a result of well designed systems and whole company culture. Not easy to do and something that requires eternal vigilance and support.

LangdonStevenson wrote: DonBC - Hurray for math and science! It really does suprise me when simple mistakes like this are made in engineering and design. We understand all of the basic principals involved here - we just have to apply them!

LangdonStevenson wrote: So when I pulled the drive shaft out, this is what I found! On the left of the image is the outboard end of the shaft with the bearing still in position. You can see that it’s a very clean break thankfully. On the right in my hand is the inboard end of the shaft that fits into the gear box bevel gear. The break occurred right on the shoulder that locates the bearing. I’m supposing that the very sharp corner created a stress concentrator that lead to a little crack forming. The last time I ran the machine I was improving an old V ditch and I got the left side chain box hung up the berm of the ditch and the wheels lost contact with the ground, so the all torque of the motor was going through just one shaft - which had this fatal flaw. And then it broke. Anyway, I should have the new shaft next week and assuming the inner bearing is ok I can put it back together. Frankly, cleaning out the years of gunge in the chain boxes is going to be a bigger, nastier job than replacing the drive shaft. I’m seriously considering drilling and tapping a new drain hole in the chain boxes as the one that is in it is about 10mm above the bottom of the box, which isn’t very helpful.

Check the new shaft to make sure there is a radius where the shoulder is. If not, it would pay you to have one machined in it. Stress risers occur without one.

That is the same way with my 11-B dozer. I know enough people needing work from a medium sized machine it will pay for itself in just a couple of small jobs. Running near perfect with no mechanical problems I'm aware of it a large bonus of course to start out with. Like you, a medium sized machine is much easier to move than something larger. Though not as productive on a large job, (not my focus) several small bites will get the job done. With no debt or encumbrances on a machine, you can charge less and still operate profitable and productive which on the backside will get you more work. I've only done a couple of small jobs for family for some very poor wages, but I've certainly learned lots as there is no better training than time in the saddle. These basically low paying jobs have garnered other work in the same area for others whom had they not seen me would not have materialized. Nothing like completing one job to throw tires down to cross the street to start the next. Now I just need warm weather.....

Edited by Codger - 05 Jan 2024 at 5:14pm

I have a full size grader setting out back  Adams  411 - vintage of around 1938/40 or so and with a IN UD-4 4 cylinder gas / diesel power . 
 All mechanical blade system and steering - something i have not used in 20 years - now if someone needs a grader ???? 

Edited by LangdonStevenson - 05 Jan 2024 at 6:34am