D4 leaky final drive, loose sprocket

I would say that getting the bearing tight may not cure this seals problem, but getting the turning parts turning concentrically in a stable pattern can only improve a good seals sealing performance.

It's looking like its going to have to come apart anyway, which isnt so much of a worry as I have a mini forklift at my disposal now.

I spun the collar used to tighten up the final drive bearings but i would have had to spin the collar in 4-5 times before the sprocket would tighten, and it still had maybe a 1mm play.
i looked at it and went nup' , somethings not right here.

I spoke with Joe cammileri and showed him my pinion gear and the chips on the outside of the teeth. he was immedieately concerned and said there are two things that do this. either your dead axle is bent which causes the the bull gear to mesh with the pinion out of square, which is more of a problem on the wide guage then the narrow guage d4's ,or your inner bearing is shot.
when I explained about tightening the collar hetold me what i basically already knew. the bearing must be toast and it needs to come apart.
Oh well I say. I would rather do this now then have to do a pulldown later on for the second time.
the other side feels tight and rolls good. so i figured I might just leave that well alone.

Sorry to hear of the new problem, but you are a smart fella and it won't hold you up for long!😆 Just remember when you replace the bearings on that pinion to buy them as a set, and not do what I did and just buy a new roller bearing because the race looked OK, luckily Joe was visiting me then and we couldn't get the new roller into the race no matter how hard we tried and I kept thinking I must of screwed up and bought the wrong bearing, but no, Joe told me he'd had that problem himself before, where a roller bearing from one reputable bearing company will not fit into the correct matching race from another reputable company. Being a dumb farmer I never realized that could be possible!!😆

So off we went to the local bearing shop and bought a new race which fitted the new roller perfectly, I would of kept hitting that wrong roller in with my big hammer till it fit!!!😆
Good luck
Mike

Having lost of experience with metallurgy, I would recommend a magnaflux or at least a REALLY good look at that gear before resuing it. I build a lot of transmissions and see a lot of gears that look great and even sneak by some mechanics but because many gears are made from a low carbon 8620 or similar and case hardened via carburization, abnormal or uneven forces on a gear can start a crack from the "crispy" outside and move towards the center. Because only the surface is very hard, a crack can develop and still function for a short while before propagating and failing. Usually debris will get caught in the mesh of the teeth and over load the gear tooth face and crack it.


In short, look very hard for cracks and deburr any sharp edges. Magnaflux is a cheap way to look for cracks you cannot normally see.

[quote="fastline"]Having lost of experience with metallurgy, I would recommend a magnaflux or at least a REALLY good look at that gear before resuing it. I build a lot of transmissions and see a lot of gears that look great and even sneak by some mechanics but because many gears are made from a low carbon 8620 or similar and case hardened via carburization, abnormal or uneven forces on a gear can start a crack from the "crispy" outside and move towards the center. Because only the surface is very hard, a crack can develop and still function for a short while before propagating and failing. Usually debris will get caught in the mesh of the teeth and over load the gear tooth face and crack it.


In short, look very hard for cracks and deburr any sharp edges. Magnaflux is a cheap way to look for cracks you cannot normally see.[/quote]

What is Magnaflux and how does it work? Is it possible to rebuild and reharden a gear like that if there were no new or good secondhand ones available anywhere?
regards
Mike