A simple bearing is ok to smack on but people should really be using bearing heaters especially for more complicated bearings like the front wheel bearings. A good bearing heater will last a wicked long time. I used to use mine every week and I bought mine used.
Types of bearing heaters:
Cone bearing heaters - Simple of the two. Uses an electric element to heat a stepped cone to accomodate various types of bearings. WAY cheaper than induction type but not $100 cheap.
Induction bearing heaters - Uses magnetic fields to heat up the bearing. Works great to evenly heat bearings regardless if tapered or odd shaped (i.e. the outer race of a front wheel bearing is the hub.)
The one above is the one I use and it works awesome. It is one example. There are many different types of induction bearing heaters but the one above is priced right at $2400. The SKF ones hover between $3800 and $4500. A cone heater ranges from $350 to about $750.
The last thing you want to do is fatigue the spindle/shaft and the bearing by smashing it on with a hammer. Or if you start the bearing on crooked, you can really do some damage. Heating the bearing to the proper temperature you can literally push on the bearing effortless by hand.
Properly replacing a bearing:
Choose the right puller for the job. I prefer 3 jaw puller as much as I can. Why to they make 2 jaw? Some jobs you just don't have the access. Some jobs you need the dealer puller. Regardless some bearings you need a lot of pressure to break free from their shafts and jimmy rigging is asking for trouble.
Sometimes bearings break and you leave on the inner race while the rollers and outer race come off. Some people I know use a die grinder on the race to cut slots in at least 2 points. Then use a cold chisel to crack the race off. Great idea except many times you cut into the shaft. Bad idea.
The way I take off stuck bearings if I load the puller on the bearing race. Then I use a torch to gently warm the race. When the race expands ever so slightly you'll hear a pop and the race will be free to pull off without heat. You'll never heat it enough to temper the spindle unless you go ballistic and heat the race to a put you could just it with a torch. Bad idea.
Sand with fine emery cloth the spindle. Obviously if there is something so bad you need a die grinder to get rid of it, you may want to rethink reusing the spindle/shaft. Once you're done sanding, spray it all down with brake/electromotive (same stuff) cleaner.
Some people also put antiseize on the shaft before putting on the new bearing. I don't unless its spec'd too. Some jobs require loctite 609 (green) or 262 (red). On turbines I use it. On BMW's I dont.
Take the new bearing and heat on a bearing heater. Use a heat crayon with desire temp. I usually use a 250 degree temp crayon. Once the back and front of the bearing melt the crayon, wear thick gloves and quickly take the bearing off the heater, line it up straight with the shaft and push on. If done correctly it will just slide right on.
If there is a nut to put on now is a good time to do it as you have a few minutes before the bearing cools and the drag of the shaft will have to be overcomed by the torque putting it on and you may not be able to torque it correctly.
And presto! Bearing changed.
Types of bearing heaters:
Cone bearing heaters - Simple of the two. Uses an electric element to heat a stepped cone to accomodate various types of bearings. WAY cheaper than induction type but not $100 cheap.
Induction bearing heaters - Uses magnetic fields to heat up the bearing. Works great to evenly heat bearings regardless if tapered or odd shaped (i.e. the outer race of a front wheel bearing is the hub.)
The one above is the one I use and it works awesome. It is one example. There are many different types of induction bearing heaters but the one above is priced right at $2400. The SKF ones hover between $3800 and $4500. A cone heater ranges from $350 to about $750.
The last thing you want to do is fatigue the spindle/shaft and the bearing by smashing it on with a hammer. Or if you start the bearing on crooked, you can really do some damage. Heating the bearing to the proper temperature you can literally push on the bearing effortless by hand.
Properly replacing a bearing:
Choose the right puller for the job. I prefer 3 jaw puller as much as I can. Why to they make 2 jaw? Some jobs you just don't have the access. Some jobs you need the dealer puller. Regardless some bearings you need a lot of pressure to break free from their shafts and jimmy rigging is asking for trouble.
Sometimes bearings break and you leave on the inner race while the rollers and outer race come off. Some people I know use a die grinder on the race to cut slots in at least 2 points. Then use a cold chisel to crack the race off. Great idea except many times you cut into the shaft. Bad idea.
The way I take off stuck bearings if I load the puller on the bearing race. Then I use a torch to gently warm the race. When the race expands ever so slightly you'll hear a pop and the race will be free to pull off without heat. You'll never heat it enough to temper the spindle unless you go ballistic and heat the race to a put you could just it with a torch. Bad idea.
Sand with fine emery cloth the spindle. Obviously if there is something so bad you need a die grinder to get rid of it, you may want to rethink reusing the spindle/shaft. Once you're done sanding, spray it all down with brake/electromotive (same stuff) cleaner.
Some people also put antiseize on the shaft before putting on the new bearing. I don't unless its spec'd too. Some jobs require loctite 609 (green) or 262 (red). On turbines I use it. On BMW's I dont.
Take the new bearing and heat on a bearing heater. Use a heat crayon with desire temp. I usually use a 250 degree temp crayon. Once the back and front of the bearing melt the crayon, wear thick gloves and quickly take the bearing off the heater, line it up straight with the shaft and push on. If done correctly it will just slide right on.
If there is a nut to put on now is a good time to do it as you have a few minutes before the bearing cools and the drag of the shaft will have to be overcomed by the torque putting it on and you may not be able to torque it correctly.
And presto! Bearing changed.
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