use an automotive parts cleaner or just spray them down with starting fluid. Check the play to make sure they are still within spec. Dry and re-grease.
before you spray with cleaner, roll the bearings on a paper towel, to get all the excess grease off. Some people soak them in a bowl of gas.
Just make sure they roll freely, and no rollers are flattened, and make sure the trim around the egde is not beaten up.
Use lithium grease.
For the price of new ones I would not put the old ones back in. Clean the old ones and pack them as spares should an emergency happen when you are on the road.
Just my thoughts though.
Bearing are actually pretty robust. There are a lot of bearing that get changed out simply because of ignorance. Most people don?t know the difference between normal wear and tear and the conditions that lead to imminent bearing failure. I don?t replace my bearings until I see signs of flaking (spalling) or pitting. The bearing on my trailer are 4 years old and are still in good operating condition.
All that protects a bearing from damage is a very thin film of lubrication. Using things like engine cleaners, carb sprays etc. remove this protective coating which leaves the bearing open to oxidation and scuff damage. You want to use something like kerosene or diesel fuel that provides some sort of lubrication while still cleaning the bearing. And what ever you do don't spin dry the bearing using compressed air after cleaning. Talk about trashing a bearing surface
Here is an excellent write up on identifying bearing failures and their causes. I would recommend that everyone who does their own bearing work read this very informative brochure.
Not all grease is made from the same base. You don't want to mix bases. If they are both lithium, that is fine. I use Sta-Lube marine and it is not a lithium base.
Besides the pitting on the bearings/cups (race), look for overheating marks (tempered blue etc) and if there is fine shards of steel in the old grease, odds are the bearing are letting go.
...There are a lot of bearing that get changed out simply because of ignorance. Most people don?t know the difference between normal wear and tear and the conditions that lead to imminent bearing failure....
Agreed. I have repacked wheel bearings all my life from back when I was a teen- to a lot of observer's horror. "Don't be so cheap and just replace them" is something I have heard! But it takes just as long to grease a new bearing as it does to repack the old one.
Most of the frequent bearing replacers I know never check their end play or takeup. I think that kills bearings almost as well as not having enough grease.
