Removing a seized bearing from a headset cup (mountain bike)

[many_methods]

So after finding my handlebars were incapable of turning without brute force, it seemed appropriate not to ride the bicycle until I'd fixed it. So I've disassembled the headset bearings to find them both seized. The top bearing has fallen apart and now the bottom shell of the bearing race is stuck inside the cup mounted in the frame. As the cup is wider than the bearing, I can't strike it from below. Ive tried tapping a screwdriver/wedge in between the cup and bearing also to no avail. The whole thing has been left to soak in a blend of penetrating oil and tears for the last 48hours but it's still stuck solid.
My current thinking is to carefully Dremel a slit through the bearing shell to release the tension and (hopefully) tap it out from there. Any other thoughts before I go at it with power tools?

 

[lchris21]

Couple of suggestions, assuming its not carbon
If you have a welder, run a small bead on it, usually enough to get it loose. If not run it close enough to the edge, create a lip as something to hit against.
Heat gun might do the same trick
Otherwise slit it with a Dremel type tool as you've suggested.

 

[Agroshield]

Using similar science to above (differential expansion), warm the headset area up with a hairdryer/hot air gun and then use an inverted can of compressed air (or pipe freezer spray if rich) to cool the inner.

Does the cup itself remove from the frame? If so, do so and drill a wee hole somewhere so you can hit the inner race with a punch.

 

[Nick DV]

You need something like this. Shop around as there are all different types

Young Wolf Bicycle Headset and Bottom Bracket Installation Removal Tool, Bike Bearing Press-in Tool for Bike Headset BB Bottom Bracket Repair Parts Bike Cycling Equipment : Amazon.co.uk: Sports & Outdoors

Shop Young Wolf Bicycle Headset and Bottom Bracket Installation Removal Tool, Bike Bearing Press-in Tool for Bike Headset BB Bottom Bracket Repair Parts Bike Cycling Equipment. Free delivery and returns on all eligible orders.

www.amazon.co.uk

 

[Craig-SM]

You need one of these tools and give it good whack and the bearing race will pop out.

https://www.amazon.co.uk/Manolyee-Bicycle-Headset-Removal-Aluminum/dp/B0CGKKZSL2/ref=asc_df_B0CGKKZSL2?mcid=39e5fc4a1593388e9e760368ab7f12c4&tag=googshopuk-21&linkCode=df0&hvadid=707288977593&hvpos=&hvnetw=g&hvrand=9152724751527777713&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9217899&hvtargid=pla-2404791529133&hvocijid=9152724751527777713-B0CGKKZSL2-&hvexpln=0&gad_source=1&th=1

 

[arther dailey]

weld a stiff bar between each side of cup, wack out fom below.

 

[many_methods]

Thanks, yeah I should be able to zap it with the welder without heating much else up. Fortunately it's an alloy frame rather than carbon. The removal tools will remove the cup but I'd rather leave that in situ if I can. I'll give it another shot this evening. Thanks all

 

[Craig-SM]

Thanks, yeah I should be able to zap it with the welder without heating much else up. Fortunately it's an alloy frame rather than carbon. The removal tools will remove the cup but I'd rather leave that in situ if I can. I'll give it another shot this evening. Thanks all

If the race is seized into the cup I don’t see the point in keeping the cup as that will be knackered too. If you remove the cups you can at least attack the race with fear of damaging the frame.

 

[Shiny Steve]

Are the cups plastic, (some are) if so welding will damage anyway, the plastic cups normally separate from the bearings quite easily when out of the frame.

What make bike is it?

 

[carbon]

the plastic cups normally separate from the bearings quite easily when out of the frame

I have an older specialized mtb with a press fit bottom bracket the bearings were bonded into the plastic holder. Warming the plastic gently released the bearings without any damage