Riveting differential gear

My 530 differential had loose rivets allowing the ring gear to slip a little and would cause a heavy clunk noise. I decided to replace the washers and rivets. But it wasn't something that I had done before. So I was thinking about how to best do it and decided to make tools that would let me squeeze the rivets in a press. The peen that I used to upset the rivets is a regular 1/4 inch rivet tool, purchased from Wick's Aircraft supply. Normally that tool would be used against the head of the rivet and a bucking bar would be used to upset the other end. But I used it the other way around in the press. I had another tool I made to support the head of the rivet and used the hardened peen to upset the other end. The result was acceptable and was done with the max I could get out of a 5 ton jack. On the differential and the bull gears, the outer ring gear is actually held from slipping by the heavy washers. The rivets just hold the washers in place. I found that the new washers from John Deere were about .030" small and I felt that if I used them I would likely still have a problem with slippage. So I decided to make my own washers that were sized properly.

Here's what I mean. While the rivet seems to be set against the bore of the washer and it all seems tight, it probably is not swelled along its shank to fill the bore down in the hub. It is probably trapping the wahser with spill over from the flare, which is not all that you need here. As such, I would expect that after some hours of heavy pulling, the loss of contact will return along with the clunk.

Any that I have had to replace I have used the hot-set nethod and I have been very pleased with the reulting durability. I could be wrong and this repair could be destined to work well for you, but I would have hot-set them, just like they were set by the factory. There's a reason they used that method, just like they use on bridges and ships.

Not trying to be critical, just hoping you won't have to tear it down later on.

Frank

Frank

I agree that the old rivets did appear to have been hot set with a much stronger tools certainly than what I can come up with. I don't currently have a 500 ton Verson or Minster OBI in my shop Frank ; ). I thought about putting replacements in hot, but it seemed too difficult to heat the rivet, and then try to assemble with washers on both sides, and then get proper support to set the rivet before it had completely cooled. Perhaps I could have heated them some just on one end before setting them.

Both the old and the new John Deere washers appear to be made by a punch press operation. That is to say, they aren't exactly "precise" pieces of hardware. The inside and outside edges on those washers all have tapers and they are a loose fit in the counterbored hole and on a new rivet. There wasn't any appreciable wear on the old washers, and the new replacements were identical in every way except color. Using either seemed to be doomed to the same type of failure because of not having close tolerance fit on the outside diameter. Or to put it another way, with the washers being too small diameter to fit tight in the counterbore hole they go into, I didn't think that I could get a durable repair, no matter what method I used to secure them. Why did this design fail in the first place is what I am after. My approach and thinking on this was that the failure occured because the old washers were too small on the outside diameter, which allowed over time for the ring gear to begin slipping back and forth, I estimated about thirty thousanths, maybe a little more. Thirty thousanths on the ring gear turns into a an inch or two with a clunk noise at the back wheels. By making washers that eliminate any potential ring gear movement in the first place, I am of course hoping to have a durable solution. In order for it to fail, the six washers, or the six ring gear/hub counterbore holes are going to have to suffer damage. It seems to me only then would the rivet start to carry some shear load. So I am not to worried about the way those rivets were set.

Having said all of the above, I admit that I am not an engineer and I could be all wrong in my approach. I put this on here to hopefully get a few other opinions and learn from other's experience. I do appreciate others taking from their time to offer comment.

Maybe this tractor had a hard life of heavy pulling and/or back and forth uses ? Someone maybe even engaged the clutch real hard every time ?

Only other thing I can think of that may cause future problems is that if those parts were not originaly made with a tight enough press fit.

Time will tell or maybe it won't ? If it is like mine they don't see a hard life anymore.

Looks like you did a fine job of fixing it. I once had a 440 crawler and the final drive gears were made like that and went through at least 3 different design changes beefing them up. In my quest for used parts I could not find enough of the latest heavy ones and changed a gear like that around to another hub. I didn't end up with near as good of looking job and my washers didn't fit anywhere near that good as the holes were not lined up good ,as they were from different assemblies. I think you will be fine as I ran this crawler for years and didn't notice any problems.

CPeter

The end result can often be an improvement over the original design, but surely must be as good to truly be called RESTORATION. The main thing when doing a bit of new engineering is to record the action in the ship's journal -- as you surely have. It appears that you have achieved both objectives! Well Done!

Here are my tools, along with old and new rivets, old and new washers, and my homemade washer. I have loose rivets on some shift forks so I'll get some more use out of these tools.