Unseating roller bearings

[2Busy]

Our treadmill recently got noisy—bad bearing in the front roller, so thought I’d replace all four (front and back) while I was at it. Watched a couple YouTube videos and thought this was going to be easy—remove a snap ring on the axel, pound the axel part way through and then reverse it a bit off-center to unseat one bearing, then come in from the other direction and do the next. Wellll…my machine doesn’t have external snap rings so I don’t know how you’re supposed to get the axel out or unseat one of these bearings. There’s obviously something on the inner side of the bearings that holds the axel in place. I hammered some on the axel thinking that might unseat the opposing bearing but I didn’t want to go too hard not knowing what I’m dealing with. Never done this before…anybody have some experience with roller bearings or treadmill repair?

 

[ericm]

The shaft is probably an interference fit in the inner races. There may be a spacer on the shaft to keep the inner races spaced apart properly and allow the roller to be pressed over the shaft without putting side force on the bearings which will damage them.

I'd first look for a part that fits at a place like surplus center. It's a long shot but if you get lucky it'll save some hassle. There may be other sources for parts.

Pressing the shaft out (or hammering on it) will damage the bearings, so make sure you have new ones first. If you heat the inner races it'll be easier to get the shaft out but will probably finish the bearings off.

 

[2Busy]

Thanks Ericm, I’ll try pressing/hammering after applying some heat. I’m replacing all four bearings, so not worried about damaging the existing ones. They’re readily available, OE is a Fafnir and I can also get it in a Timken. Any opinions on those manufacturers or others?

 

[engineer2]

It's probably pressed together. Don't hammer on the end of that shaft. If you mushroom it, you're going to make it impossible to remove the bearing.

 

[NWOhioChevyGuy]

Timken is my goto for bearings or SKF.

 

[2Busy]

Didn’t take much encouragement at all, I just wasn’t being tough enough. Thanks everyone for all the help. Will order new bearings (I think I’ll go with Timken) and get it back together. This is a 20+ year old True treadmill. Nice to be able to keep it rolling and avoid full replacement fir now!

 

[2Busy]

Didn’t take much encouragement at all, I just wasn’t being tough enough. Thanks everyone for all the help. Will order new bearings (I think I’ll go with Timken) and get it back together. This is a 20+ year old True treadmill. Nice to be able to keep it rolling and avoid full replacement fir now!

 

[nadogail]

I recall Phil Wood bicycle hubs that had pressed in ball bearings. It has been almost 50 years and I think they were also held in with LockTite.

 

[ericm]

Yea a lot of bike hubs have pressed in bearings. The ones I've worked on didn't need loctite.

When you re-assemble it, make sure to not put force through the bearing rollers or balls themselves as that will damage them. If the press fit is on the inner race, you put force on the inner race. Same for outer. If it's both you need a cylinder with a bore slightly larger than the axle and a diameter of the outer race (or larger if it's flush) so it will press on both inner and outer races.

 

[Beau Nugget]

I would just like to say kudos to you for using a treadmill enough to wear out the bearing. Well done! I’m sure it will come apart somehow. Good luck!

 

[2Busy]

I would just like to say kudos to you for using a treadmill enough to wear out the bearing. Well done! I’m sure it will come apart somehow. Good luck!

Haha, well my wife gets most of the credit, and a lot of that was back during her marathon training years (gosh, that was a while ago!). We’re both daily walkers now and the treadmill only gets used when the weather‘s really bad. Just glad we can keep it in commission a while longer.

 

[FredWanaker]

throw the new bearings in the freezer for a couple hours before installing them. Numbers usually go outwards. Use a heat gun or hair dryer to warm up the flange that holds them, then grab the bearing from the freezer to put it in. That way you are shrinking the bearing and expanding the flange which will make it easier. If you have to pound on it use either a flat block of oak, or the old bearing. Hit the oak or the old bearing with the hammer, while it sits on the new one, do not hit the new bearing.

 

[Doug]

Those are 203 bearings that can be commonly found in any starter-alternator rebuilding shop. I prefer the sealed (rubber seal) version over the shielded (what you have now).