I recently scored a 10 bolt posi from a 72 Nova for my 49 Chevy coupe and was in the garage working on it when my neighbor, who used to be a auto shop teacher walks over and looks at it. The ring and pinion gears have rust on them and he says they are junk. The rust looks like it could easily be removed in blast cabinet with some glass beads. I was just gonna blast them and run em, but he says once they have rust on them, they are junk because they become pitted and weakened, is that true? They guy has built several cars and taught auto shop for likw 20 years so I try to listen to him but damn new gears are expensive!!
Don't use glass or sand they are like little hammers Walnut shells It will take time...... if in the end they are micro pitted they will just whine ......
don't see any problems using glass? we use it on aerospace bevel gears all the time in our FAA repair shop??
I would glass bead it. I also am in the Areospace industries and it is common practice to clean parts with glass bead. Keep moderate pressure and dont dwell in one area. The gears in my car were sitting in a housing behind a friends shop for years. The portion of the gears that were not in the oil had a light surface rust on them. I cleaned them with some scotch brite and fresh oil and reinstalled them 12000 miles ago.
Run it, and change the oil after a few miles. I've seen some really bad ones that never made a sound.
If it is not bad I would just steel brush it and run it and change oil later but if it feels rough and is a little deeper it needs blasting. That rust is like sand and will eat up the gears and bearings if it gets in the oil it's like grinding compound. I had that happen to a steering box.
Im with Groucho & Andrew....... Wire wheel it off and RUN IT ! Why go thru the hassle of taking it apart to glass bead them ? Its more of a job & if you dont know how to set the lash its gonna cost you more than the 10 bolt is worth. Wire it off, Fill it with 90wt, run it, Change the oil after a 100 miles or so.
I'll vote for chemical (or any non abrasive) strip. If you decide to wire brush it or run it the way it is, put a magnet in the bottom of the case to catch some of the rust and anything that sheds off of the gears. I've had pretty good luck cleaning up gears that just had surface rust and reusing them.
Is it rusted evenly across the ring gear? If it's pitted in one section more than another you could run into vibration problems caused by to much backlash variance, being the rusted/pitted areas would have more backlash than the cleaner surface.
If there is pitting in the area of the gear contact line you have a good chance that running the gear it will eventually go bad. Anything outside of the contact line doesn't matter much. I go with the bead blast idea and run it. Rex
Just run them like said before. My Chev 4x4 gets like that all the time from being in the mud and water then it sits for months at a time. I only change the oil when it turns milky.
Ok, I think I will blast them lightly with glass beads or maybe even baking soda. Our mechanic at work offered to rebuild the whole rearend for $75 (labor) if I took it apart and cleaned it and brought it to him. He's a ASE master mechanic and says they are no problem so I guess that sounds like a deal to me?
A little bit OT but I've got a couple of new cams (still in the boxes) with just surface rust on the cam bearing journals. Lobes are still coated. How would you clean them up? I'll start a new thread if needed.
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