what grit sand paper would you use for cleaning out axle tubes

I would NOT use Scotch Brite near any Bearing surface. That stuff is BANNED from jet engines because it goes straight for the bearings and stays put and eats them alive!
 
...I've used it before to clean off a mating surfaces for bearings, you just have to be surgically meticulous with your cleanup before putting stuff back together.

gotta keep in mind here though shaker, jet engines run a lot tighter tolerances, with a much narrower margin for error...like less than a tenth or even a hundredth of what most automotive engines use, and they use much thinner oil...if your typical car engine runs between 0.001"-0.002"...not even to speak of the wide clearances on axle bearings, my shift super is a backshop jet engine tech, and remembers numbers stretching out past four digits, so naturally, one of those little fibers will reek havok on jet engines bearings...but I do know what you're talking about...we're not allowed to use it either
 
txstang84 said:
...I've used it before to clean off a mating surfaces for bearings, you just have to be surgically meticulous with your cleanup before putting stuff back together.

gotta keep in mind here though shaker, jet engines run a lot tighter tolerances, with a much narrower margin for error...like less than a tenth or even a hundredth of what most automotive engines use, and they use much thinner oil...if your typical car engine runs between 0.001"-0.002"...not even to speak of the wide clearances on axle bearings, my shift super is a backshop jet engine tech, and remembers numbers stretching out past four digits, so naturally, one of those little fibers will reek havok on jet engines bearings...but I do know what you're talking about...we're not allowed to use it either

We cant even use it on the Fancase of the Engine to touch up a minor defect as somehow the fibers will still end up inside the engine. Yes Bearing clearance is different, I just figured it was better to be safe than sorry as rust from sitting over night should be able to be cleaned off with a solvent as it is just going to be on the surface.
 
yeah, i know, i just got into a discussion with my shift super about that one...he just failed an inspection for fod inside the guide vane struts on an engine this evening...

i see where you're coming from, and i know how bad that stuff can be to bearings, but axle bearings are pretty forgiving, they'll probably chew that stuff up and spit it out...at any rate, as long as he's clean about it, all should be right with the world :nice:
 
Shakerhood said:
We cant even use it on the Fancase of the Engine to touch up a minor defect as somehow the fibers will still end up inside the engine. Yes Bearing clearance is different, I just figured it was better to be safe than sorry as rust from sitting over night should be able to be cleaned off with a solvent as it is just going to be on the surface.

FOD is a very serious issue in aerospace. I spent six years as a structural mechanic on the 777. The stories I could tell.:nonono:
However, it should go without saying that after cleaning rust with any abrasive, things should be cleaned. Not only to clean up the abrasive, but also to remove the rust debris, which can also cause damage.
Sand paper grit will wreak just as much havoc on bearings as those little fibers. My thinking was that the scotch brite will not gouge up the bearing mating surfaces as bad, and won't remove as much material.

Good luck with the rear end rebuild, let us know how it comes out.
jason