Of course, replacing a squeaky or whistling bearing is always easier than lubricating it. But it is not always possible to quickly find the required replacement sample. Therefore, in some cases, it is still easier to lubricate the bearing than to waste time looking for a new one. Especially if the bearing does not roll and is quite suitable for further use.
There are no issues with open type bearings; just wash them and apply lubricant. But with closed ones there is a problem of removing the metal washers on the sides. The fact is that they are very easy to damage and then they will become unusable.
But there are 3 tests on how to lubricate a closed type bearing without disassembling it. Despite the fact that the products at first glance seem almost sealed, this is not entirely true, because the gap between the inner ring and the protective washers is quite enough to introduce lubricant.
So, let's go from the complex method to the simplest.
Preliminary actions
The first step is to rinse the bearing from all external contaminants. To do this, dip it in any solvent or degreaser for 5-10 minutes.
Then wipe dry with a rag.
Method 1: lubrication of a sealed bearing using a vacuum pump
We heat the lubricant to 60 degrees Celsius. We put the bearing in it. In fact, he should drown in it.
Next, we place everything under the vacuum pump.
Vacuum for 15 minutes. Next, we slowly release the vacuum.
The vacuum will force all the air out of the bearing, then the pressure will force the lubricant in. More details here - https://enn.washerhouse.com/8322-kak-smazat-zakrytyj-podshipnik-gustoj-smazkoj-bez-razborki.html
This method is one of the best, but not available to everyone due to the lack of a vacuum pump.
Method 2: lubrication of a closed bearing without disassembly by injection
Take a plunger syringe with lubricant. Holes are made in the wooden block. On one side under the bearing, on the other under the tip of the syringe.
We insert the bearing into the block, on the other side there is a syringe. We plug the bearing hole with a round cap and pump in grease. It will definitely be pressed through the bearing gaps.
More details here - https://enn.washerhouse.com/7971-kak-smazat-zakrytyj-podshipnik-bez-razborki.html
Method 3: heating the bearing in grease
The simplest and most accessible way to everyone. We take a metal container and put the bearings in it. Apply thick grease on top. There is no need to feel sorry, it should close the bearings with a margin.
Next, on a gas burner, heat the lubricant to a liquid state and “cook” for 15 minutes.
The main thing here is not to overheat the lubricant, as it may lose its properties. It is advisable to constantly stir the composition and heat over low heat. Also control the temperature and do not exceed it above 100 degrees Celsius.
Then we put the danka aside and leave it to cool.
When heated, excess air will come out of the bearing, and when it cools, lubricant will enter due to the vacuum created.
