Installing planetary shafts in final drives?

How do you install the planetary gear shafts in a D6H (or similar) final drive carrier? The book says lower the temp of the shaft and press into the carrier to the retainer to set the preload on the bearings. I would like to know how tight they fit? Can they be knocked in with a sledge? Or how big of a press would I need and what temp do you lower the shafts to?

I had 2 of the shafts work loose and leak oil around the retainer on my dozer and I'm replacing the carrier. I need to swap the gears/bearings from the old one onto the new one. I may need to replace the shafts if they are worn. The shaft would turn when I would try to tighten the retainer bolt. Hopefully I caught this before it becomes a bigger problem. Lots of questions.

Thanks!

Without digging into a book my self, the lowering of the temp on the shaft would be done with dry ice. Last one I did was a pivot shaft on a 9N. Buried it in dry ice for 2 days and still had to use another machine to push it thru. In your case, I'd bury the shaft in dry ice for at least a day. Then when ya get ready to press the shaft in, preheat the bearing inner race.There are several methods to do that. One is an oven, the other is the way I have always done. An older fella , may he rest in peace, showed me this. If you can lay the bearing on a flat piece of plate, works best. Take a torch, cutting head if the bearing is smaller ID than say 3 or so inches, rose bud if larger. Never stop moving the flame in a circular motion around the inside of the race as long as it is close( meaning within say 6 inches) to the race. It will ruin the race thru distortion( keep the tip in the 3or4 to 6 inch range from the piece you are heating). I suppose you could have a glass of water to work from, but I was told to spit on the race and when the spit just started to "dance", stop heating and get to assembling. Make sure ya have some good thick welding gloves and you definitely have to work quick. If you do it correctly, the shaft will slip right in and as the heat leaves the race it will be locked in place. Just make sure that you have it all the way in and where you want it to stay as once the heat goes, it is a bear to make any corrections. As for a press, a 50T would work, maybe a 25 ton. I have a 50 ton that works for most anything I need it to do. Good luck with your repair.

If you can get hold of liquid nitrogen from your local gases supplier that would be the way to go. Usually they will rent you the flask it comes in for say 48 hours and the cost of the liquid itself is peanuts. It will drop the temperature of the shaft to like -300 degrees, as opposed to dry ice that only goes down to -80 or so. Frozen that way your shafts should literally fall into place. They are so small you wouldn't need more than a couple of gallons.

I can tell you from experience that the shafts will not go in with a sledge.

I've often sacrificed an old beer cooler (just so I could justify a new one of course!) to use as an insulated container for freezing parts. Be ultra careful if you are using liquid nitrogen - you need full skin protection, welder's gloves, eye protection, etc, because if it splashes on exposed skin it will BURN you horribly. Even though saying that it is an awesome tool to freeze parts, and perfectly safe so long as it's used with care.

Nige said:

I've often sacrificed an old beer cooler (just so I could justify a new one of course!)

Click to expand...

Riggy jots that bit of info down for future use.

Thanks Nige

You will find that the new pins will bang in easy, once they have fretted about in the outer cover leaving their tear stains on the outer case it usualy means that a new cover/ or repaired cover is needed, so dont get to keen to empty the freezer just yet try a new pin in the worn location??