Monday, October 22, 2012

How to pack trailer bearings

Packing wheel bearings is very simple. It takes less than an hour for even inexperienced mechanics. Make sure to support the trailer at the axle and tongue as well as chalk the tires and support the back of the trailer. You don't want the trailer to tip over in any direction.The first thing to do is remove the wheel. Use an impact hammer or tire iron.


Next, take a pair of channel locks and remove the cap. You may need to twist it off as some are threaded or you will just need to gently wiggle it back and forth until it comes loose. You should have a tray or bucket close bye to put all of the parts. They need to stay clean especially the interior parts such as the bearings, seals and cap.

Once you remove the cap you will see the lock-nut and cotter pin. Bend the cotter pin straight and pull out the cotter pin with a pair of pliers.  You should be able to remove the nut with your fingers. You may need to use a wrench; however it should not be very tight.

When you remove the nut you will see a metal washer with a tab on it that lines up with a groove on the axle. Remove the tab with the help of a screwdrive and set aside. Remember to keep all of the parts free of dust and other particles that may get into the bearings.

It is not held in by anything at this point. To remove it gently pull on the hub until the bearing moves to the end of the shaft then push the hub back so you can easily remove the bearing. Put it in a clean place.
You are now able to pull off of the hub. Be careful, depending on the hub the inner bearing may not be held on tight. Don’t try to remove the hub while holding the outer bearing. Just put it down and keep it clean.
On this hub there is a metal ring seal. All you will do with this is clean it and lightly grease it before replacing the hub.
Now the the hub is off we need to remove the inner bearing.
Do this one wheel at a time and don’t get the bearings mixed. The first thing to do is find a socket that is just small enough to fit through the hole where the outer bearing was. Make sure that it is a large socket so that when you hit it with a hammer it will displace the pressure so that you don’t damage the inner bearing.
Drop the socket in the hole and make sure that it cove the inner nearing and does not hit the sleeve.
Find a hammer that will fit in the socket and place the wooden end of the handle in the hole. Hit firmly, but don’t overpower it. It will probably take a few hits to get it out. Make sure that you place the hub on a clean surface so the seal and bearing stay clean.
After the bearings are removed clean them by wiping them off with a shop paper towel. Inspect for any discoloration or pits. If they look suspicious replace them. If you put it on a dirty surface and its covered in particulates replace it.The easiest way is to use a bearing packer. They are about 15$ at the auto parts store. This one used a grease gun. If you need to buy a grease gun buy the big one. It is probably cheaper than the mini and the grease is a fraction of the price.
Place the bearing in the packer and screw on the top. Make sure there is a good seal around the top and bottom edges of the bearning.
 Attached the grease gun and pump the handle until all of the dirty grease is pushed out of the bearning and clean grease is coming through.

Use some of the extra grease and coat the outside of the bearing. Also lube lube the bearning seat pictured below.

Clean this part up as well. Don't use solvent.
Lube the backside of the bearning and clean up the metal ring seal.
To install the seal just tap it in a cirular motion with a hammer. It should sit level when done.
 Now, replace the hub. Make sure that any seals or sleeves the you took off are replaced before installing the hub. When the hub is back in place. Lube the outer bearing seat and replace that bearning. Replace the bolt, cotter pin & cap. Your done!

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