GS550 Steering Stem Bearing Removal

[Joseph Christopher]

Hi all. I couldn't find a forum topic for frame queries - I hope this is the right place.
I've been trying to remove the lower bearing inner race from the steering stem - using the search function I've found posts explaining how to remove the outer races; I managed those on my own, but can't find anything pertaining to my query.

My main question here is regarding stem metallurgy. I've seen plenty of posts online stating that a blowtorch should never be used near the stem; unfortunately I read these after having done so.

After removing the roller cage and rollers, I applied a blowtorch at its lowest heat to the bearing inner race at a range of two inches for about 5-10 seconds at roughly each eighth of its circumference. I was aiming carefully and don't imagine this will have transferred much heat given the short time I actually kept the torch on it, but I'm concerned that I may have damaged or weakened the stem. As my bike will be getting used at a range of speeds, I'm worried about it failing. I might add that a mallet and chisel didn't budge the race after heating; my bike has been neglected by a previous owner and many parts are seized, which is adding to the problem.

I'd be grateful for anyone's opinions on this matter; I'd also be grateful for any ideas on how I might proceed in getting the race off the stem. There's only room for chisel purchase on one side of the race, and I don't have access to a puller. I haven't enough experience to determine how much is too much force to apply to parts, and have probably not been using enough, but I thought it best to err on the side of caution when working on parts that could pose safety issues if inadvertently damaged.

Thank you for your time!

[salty_monk]

There are a few threads on here. Some people have welded to it from memory so I guess that would put in just as much heat as you've done.

Somewhere there is a good post here about carefully grinding through it with a dremel tool & then when the cut gets thin, split it with a chisel & lever it off....

[bwringer]

...Somewhere there is a good post here about carefully grinding through it with a dremel tool & then when the cut gets thin, split it with a chisel & lever it off....

This is what I do -- cut a slot with a cutting wheel on a Dremel tool, but be careful not to go all the way through and nick the stem. Once it gets deep, but not all the way through (did I mention that you shouldn't go all the way through?), place the blade of a large ugly cold chisel in the slot and give it a good solid bang or three. The bearing race is pretty brittle metal, so it will crack, and this will loosen it juuuuuuuust enough to tap it free of the wide spot on the stem. If it doesn't crack, try making the slot a wee bit deeper, maybe use a worn cutting wheel to get a little further into the corner, and try again until it goes "ping".

You don't really need to do this twice, to separate the race halves; one crack loosens it enough to tap it free easily.

The method in this video seems like it would also work pretty easily, if you can set up some sort of rotation method -- I haven't tried it yet on a steering stem bearing, but I don't see why it wouldn't work:

Also, don't worry at all about that amount of heat used on the race. Unless you somehow melted the aluminum lower, you're fine.

Now, the trick becomes pressing the new bearing into place. I use a hunk of steel pipe with a cap on top in a hydraulic press, pressing ONLY on the inside race, but I've done it with the same hunka pipe and a large hammer as well.

[Big T]

There's a bicycle tool that looks like a badminton shuttlecock that I've used successfully

Park Tool BBT-90.3

[bwringer]

Wait, is the OP having trouble with removing the lower inner race from the steering stem, or the outer lower race from the bike frame? It's a little hard to tell from the original post

I posted instructions for the former, removing the race from the steering stem.


To remove the race from the frame, there are three main ways:

1) Run a couple of weld beads on the race, one on each side. As they cool, they'll shrink and the race will fall out. This can discolor the paint on the frame, though, so be ready to touch up.

2) As above, cut a slot with a Dremel; these will end up as curved, angled cuts because that's the only available angle. Crack with chisel as above. Then repeat, so that the race will crack into two pieces and fall out.

3) There's very, very little of the race protruding, so it's very difficult for a punch inserted from the top to get purchase. I've had success with using an angled prybar with a striking cap; you may need to dress the edge to keep it sharp so it can grab the tiny area available. You can also use a "tulip" tool as above; there are homemade versions made from conduit, but I've never had any luck with these. YMMV. Sometimes a long punch with a sharp 90 degree edge on the nose can get a grip.