Removing tight freehub bearings

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bobones
Posts: 35
Joined: Mon Aug 12, 2013 11:19 am

by bobones

Any tips for removing tight freehub bearings? I am using a Wheels Manufacturing bearing extractor and a punch, but sometimes the inner bearing does not want to budge no matter how hard I hit it. I actually broke off the tip of my punch last time I tried. Would a heavier mallet or blow torch help?

by Weenie


alcatraz
Posts: 583
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Don't know if this can help you but if you cant get a good enough position to knock the bearing out straight and even, you can try using a concrete anchor bolt and expand it inside the bearing. It will provide you with a centered surface to hit.

You'd need to find the right size. It needs to be almost the right size before expanded.

My freehub has a bearing on opposite sides. I was lucky that the internal sleeve was loose enough to push to one side and exposed a large part of the bearing under it. I was able to put a 12mm hex wrench socket (1/4 inch) on an extension and fit it exactly through one bearing. This way when hitting the opposite bearing the round socket edge helps to center the pressure a bit. Still had to go around and knock side to side though.

/a

bobones
Posts: 35
Joined: Mon Aug 12, 2013 11:19 am

by bobones

Thanks, but the bearing extractor I have performs the same function as your concrete anchor bolt suggestion so I do have a good centred surface to hit. I'm hitting it pretty hard but it's still refusing to budge so I think I'm going to buy a 4lb hammer and some penetrating fluid. If that doesn't work a blow torch might expand the aluminium shell to loosen the steel bearing.

alcatraz
Posts: 583
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Doesn't a bearing extractor rely on having an edge to expand behind? If you have a sleeve in there, there won't be any edge.

The expander doesn't need the edge and has little flex.

If the freehub is alloy it helps to heat it up before hitting the bearing. Alloy expands more than steel. So it loosens when heated. Best of course is to heat quickly and maybe get the largest gap before the outer steel bearing race has warmed up as much.

/a

bobones
Posts: 35
Joined: Mon Aug 12, 2013 11:19 am

by bobones

The bearing extractor has a collet which expands and grips the inner race of the bearing. Look at the link I posted and you'll see what I'm talking about. You then just hit it with a mallet and punch. I've used it plenty of times and it works in most cases, but sometimes a bearing will be really tight and refuse to come all the way out of the freehub.

alcatraz
Posts: 583
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Didn't see the link first.

Try heating up the freehub. Let us know how it went.

/a

pdlpsher1
Posts: 1325
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Something is wrong if you have to use a lot of force. Some freehubs have a circlip prevention the bearing from moving. Did you make sure that there’s no circlip stopping the bearing?


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bobones
Posts: 35
Joined: Mon Aug 12, 2013 11:19 am

by bobones

These are Novatec freehubs with 2 6901 bearings inside them. There is a circlip between the bearings, but I remove this once I've knocked out the first bearing. I've done this several times without too much bother; however, I have a couple of freehubs were the innermost bearing moves quite easily out of its own position, but then gets stuck near where the outer bearing sits. I'm going to use a bigger hammer and a blowtorch so something's gotta give!

pdlpsher1
Posts: 1325
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

If you have access to a hydraulic press it would take it out easily, and probably be better than a mallet/hammer as to not damage any part of the freehub.

bobones
Posts: 35
Joined: Mon Aug 12, 2013 11:19 am

by bobones

OK, so the 4lb mallet and blowtorch didn't work. I ended up destroying one freehub shell by crushing the outer lip, near the cassette threads, when I tried to press the bearing out. Fortunately, I have a few of these freehub shells, so for the next one I pressed the bearing back into the shell and used a sanding cylinder on my dremel to smooth down the inside of the hub shell a little, and the previously troublesome bearing popped out without much force.

I am not sure exactly what was happening, but I suspect the inner surface of the freehub shell acquired some score marks, ripples or other deformations which caused the bearing to jam tight.

alcatraz
Posts: 583
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Crazy. It's like they've bonded together. Sorry to hear about it. I wonder what could have been done better.

How about setting up some kind of simple press/pull jig around it next time to avoid the impacts.

You said you replaced the bearings before. Do you remember this bearing to be a PITA to install?

/a

mattr
Posts: 3412
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

TBH, just chucking a kettle full of boiling water is usually enough to free it up.

As long as you don't chuck it on yourself at the same time.

You may have twisted/damaged the shell when torquing up/removing the locknut. Some aluminium ones are pretty ropey when it comes to "tightening to spec" i.e.40Nm and some even recommend a lower torque to prevent damage to the shell (usually the thread though)

commendatore
Posts: 159
Joined: Mon Dec 30, 2013 1:51 am

by commendatore

A slide hammer is really king here. My LBS is always happy to pop them out when I walk in with a six pack.

alcatraz
Posts: 583
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

mattr wrote:
Mon Feb 19, 2018 3:07 pm
TBH, just chucking a kettle full of boiling water is usually enough to free it up.

As long as you don't chuck it on yourself at the same time.
Ouch. Sounds painful. How many times has this happened to you?

/a

mattr
Posts: 3412
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

LOL. Never.

Seen someone do it though.
Chucked a kettle full over the hub in the sink, lifted it up to move it to the workbench, poured the water that'd pooled inside it all down the back of his hand......... So the gloves he was wearing to protect from the heat didn't do much good.

by Weenie


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