Shoot your bow through a chronograph and check your speed before doing this so that you can compare the results later.With most all bow manufactures using Teflon bushings these days there is practically no maintenance to be done on the bearings and axle's. I guess I am still a little old school when it comes to this. I still remove the the cams and/or idler wheel for inspection.
I will provide a brief description of the process. First you need a bow press. Don't have one, get one. If you are reading this it means you are somewhat inclined mechanically and should have the means to perform minor repairs.
Once the bow is securely mounted in the press and the bow is relaxed just enough to provide about 1" of slack in the harness you are ready to remove the "e-clip" securing the axle in place. After this you need an object that will fit the hole in the limb tip so that when you slide it inward the axle will come out with the cam staying in place. I use a roll pin punch to do this.
I will then remove the other "e-clip" at this point. With the axle lying on a smooth flat surface, roll it while watching and listening closely. This test will let you know if it is warped and in need of replacement. If so you can relax the tension from the press and your cam and strings will stay put until you can find a new axle. Also, check the straightness at the store from where the parts are being purchased before leaving with a bad one.
If it rolls out smoothly, you will want to inspect it for any wear or marks in the finish. Most of the time there will only be a slight discoloration on the surface. In this case just grab a 3M pad in your hand and lay the axle so that it can be twisted with the opposite hand while applying slight pressure in the other that contains the pad. The axle will be shiny and clean after only a minute or so.
At this point you only need to remove the cam or idler and take a look at the bushings. I normally use a clean cloth and wipe them clean. I have not ever seen a Teflon bushing that looked bad. So the way I would test them is to lube the axle slightly with a "good" lubricant that contains Teflon. Slide the axle back into the limb and through the cam or idler wheel. Install the retaining clips. Don't forget to install both, you will look silly on the range when someone says "hey! your axle is about to fly out of there and kill you!" Yes this has happened and yes, I felt really stupid. It has not happened since!
With everything in place and the bow still relaxed in the press, move the cam or idler from side to side. Is there any movement? How much is too much? Well to answer these questions I would have to ask you what the bow is going to be used for.
On my target bows, I prefer to have the cams with a little play. I don't want a lot of friction in these spots as I am trying to obtain as much speed from the lowest poundage that I can pull. With my hunting bows, a little friction is not a problem. I would like to say that it may even cut out some noise after the shot but I have not ever tested this theory.
Ideal friction for me is when you remove the strings and cables from the cam and then hold the lobe at it's highest point. Let go of the cam and it should only rotate to the lowest point and rock slightly back and forth while coming to a slow stop. If when you spin it and it stops abruptly, it may be to tight. This is noticeable when reinstalling your cam and it's difficult to slide in between the slots in the limb. If a Teflon bushing is used there are several ways to remedy this. You can take a flat file and carefully remove a little Teflon from both sides and check the fit. It should be just a little snug. If the axle is too tight, I use a small rat tail file and hone the inside slightly. The file needs to be small enough to slide all the way through the cam bushing. Slowly and lightly is the way to go here.
With and idler wheel I will spin it and watch as it stops. Slow is good.
I should also point out at this time that a lot of manufactures are using sealed ball bearing and lubrication will not effect those at all. When there is tension applied to the bearing it will stop spinning on the axle and roll as it was designed.
To check these bearings I use a pencil and insert it into the axle hole and rotate the cam or idler while applying pressure to the bearing. If it has a choppy or rough feel it should be replaced. Most of these contain 2 bearings, one on each side. Check both! I have found numerous bearings that have failed within a year of shooting. I will go a little deeper into this in another post.
After reinstalling check your speed again. I have found that when the task at hand is complete the bow speed will sometimes increase a few feet a second.
Good luck!
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