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Idler Pulley Maintenance

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Hello my fine people,


A while ago I got a PM from a member who was not familiar with packing bearings on idler pulleys. I told that particular member that I would make an instructional thread about idler pulleys, so here we go.


Repacking idler pulley bearings only applies if your pulleys move correctly. That may seem obvious, but let me explain further.


Pulley movement is a good sign that your pulley is still functional and sound, but that is not the end of the story. If your pulley freewheels, that is, you take the pulley and spin it, and it has no resistance, that means that your pulley is probably good, but needs to be repacked with grease. However, if you lay the pulley flat on a workbench, and attempt to move the inside bearing race side to side, left to right, and there is obvious movement, your pulley bearings are bad and I recommend you invest in a new pulley.


Investing in a new pulley does not mean that you are done. You still need to pack the bearings. See below for instructions.


If your pulley does not move at all, the chances are that the inside of your pulley looks like this, and you must invest in a new pulley.




Step 1 in repacking pulley bearings on an OLD idler pulley is to remove the dust caps from the pulley bearings. You can do this with a small pick, but I have found that a combination of a box-cutter blade and very small scewdriver works perfectly to remove the caps. Be careful not to damage the dust caps when you remove them, or bend them excessively.


The next step is to clean the bearings out with the penetrant oil of your choice. My choice is PB Blaster because that is what I have in stock.


Bearings before cleaning:





Same bearings after cleaning:







Much better, right?


If you desire, you can take a stiff toothbrush and get into the bearings a bit to clean them even better. Make sure to flush the bearings very well with your penetrating oil.


Dry the pulley and bearings as best as you can before proceeding to the next step in repacking.


The next step is to get yourself a very small screwdriver, and use the grease of your choice (I recommend Lucas Red and Tacky). Press the grease into the bearings until the bearing area of the pulley is full of grease. Turn the pulley over, and do the same thing to the other side of the pulley, packing grease on the other side of the bearings.




After pulley is full of grease, press the bearing caps back into place with 2 small screwdrivers. Ensure that the caps go all the way in, squeezing out a bit of grease around the edges of the pulley bearings.




Wipe the excess grease off the pulley.


You will notice that the pulley bearings have MUCH more resistance to movement. This is completely normal, and is exactly what you want.


You have successfully repacked your pulley bearings!




Special thanks to @peter lena for teaching us all about greasing our machines!




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Good article Don - that one will live to provide seat time for quite a while.. The early machines that used the 2-piece riveted idler pulley (early 60's Round Hoods and mid 60's Square Hoods) that had the six rivets that could be removed, the 2 halves split and a NEW sealed replacement bearing installed. Re-assembly can be either rivets or #5-40 button head screws and hexnuts, with a small amount of Loctite. Even then, it's best to follow Don's and Pete's advise to remove the seals, flush, and regrease with the Lucas and re-assemble the seals. Makes a world of difference... I've done 4 so far that way...Same goes for the early PTO idler....


Edited by ri702bill
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