Tips for pressing out lower stem bearing

queen of spodes
Edited Date/Time 8/31/2014 5:01pm
Gotta replace my steering stem bearings. Have bearings and a 20 ton press. My question is will a section of PVC pipe be strong enough to let me press the bering back down onto the stem?
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JA946
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JA946 8/23/2014 6:17am
8/23/2014 6:17am
Do NOT use PVC pipe - it will SHATTER under load.
deltadestroyer11 8/23/2014 6:36am
8/23/2014 6:36am
JA946 wrote:
Do NOT use PVC pipe - it will SHATTER under load.
Wrong, I've always used a straight cut piece of pvc and it works like a charm..
JA946
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JA946 8/23/2014 7:04am
8/23/2014 7:04am
JA946 wrote:
Do NOT use PVC pipe - it will SHATTER under load.
deltadestroyer11 wrote:
Wrong, I've always used a straight cut piece of pvc and it works like a charm..
What can I say, I only speak from experience. Then again, not with steering head bearings. Mine was with wheel bearings pressing into a car hub - the PVC pretty much exploded.

Just because it works for one person, doesn't mean it will for another. Personally, flying pieces of plastic shrapnel scare me.

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queen of spodes 8/23/2014 7:33am
8/23/2014 7:33am
Yeah, it does sound a bit sketchy. I think I have some steel pipe in the shop I could use.. trying to avoid a trip to home despot.
Matt Fisher
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Matt Fisher 8/23/2014 7:40am
8/23/2014 7:40am
Wrap the PVC in a couple of shop towels, old shirt, etc. Secure with a bit of duct tape. If it explodes, that should contain the "shrapnel".
motofab36
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motofab36 8/23/2014 8:26am
8/23/2014 8:26am Edited Date/Time 8/23/2014 8:28am
heat the inner race of the bearing with a heat gun and drop it into place. Make sure your seal washer is installed first and also make sure the bearing is plenty hot so you don't get it part way on and have it stick. After its in place you can push down on it with a piece of pipe until its cooled a bit
deltadestroyer11 8/23/2014 10:42am
8/23/2014 10:42am
It's worked on every bike I've owned(8 in all). You're not putting 1000lbs of pressure on it and your only pressing it down like an inch or so..rite.
But if it makes you leery, then don't do it, I understand it's your bike and you want all work done to it to be top notch correct, just as I do on my bike. I've always used pvc that fits the innermost diameter of the bearing(not the outer taper bearing part, but the inner most part fitting very close to the stem) and long enough to stick out 2 or 3 inches above the top of the stem. Both ends need to be cut very straight. Get a small 2 by 4, sit it on top, hold steady, use a dead blow hammer and whack gently until seated in position..

But you got a press, that's even better. Maybe a pipe might be better..
FGR01
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FGR01 8/23/2014 3:59pm
8/23/2014 3:59pm
motofab36 wrote:
heat the inner race of the bearing with a heat gun and drop it into place. Make sure your seal washer is installed first and also...
heat the inner race of the bearing with a heat gun and drop it into place. Make sure your seal washer is installed first and also make sure the bearing is plenty hot so you don't get it part way on and have it stick. After its in place you can push down on it with a piece of pipe until its cooled a bit
So, this means you're putting the bearing on there with no grease in it? Otherwise the heat gun would cook it all out if you are getting the inner race hot enough to expand.

Not a big deal, but trying to pack the bearing with grease is a PITA once it's already installed.
mx5471
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mx5471 8/23/2014 5:29pm
8/23/2014 5:29pm
I had mine done at the shop. Putting it on is no problem. But how do you guys get it off?
Paw Paw 271
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Paw Paw 271 8/23/2014 6:08pm
8/23/2014 6:08pm Edited Date/Time 8/23/2014 6:09pm
Use a bearing puller/seperator.

Paw Paw
motofab36
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motofab36 8/24/2014 9:57am
8/24/2014 9:57am
motofab36 wrote:
heat the inner race of the bearing with a heat gun and drop it into place. Make sure your seal washer is installed first and also...
heat the inner race of the bearing with a heat gun and drop it into place. Make sure your seal washer is installed first and also make sure the bearing is plenty hot so you don't get it part way on and have it stick. After its in place you can push down on it with a piece of pipe until its cooled a bit
FGR01 wrote:
So, this means you're putting the bearing on there with no grease in it? Otherwise the heat gun would cook it all out if you are...
So, this means you're putting the bearing on there with no grease in it? Otherwise the heat gun would cook it all out if you are getting the inner race hot enough to expand.

Not a big deal, but trying to pack the bearing with grease is a PITA once it's already installed.
Oh they are supposed to have grease in them?

I've never had a.problem packing them in basically the same manner as you would before installing. Dip finger in grease, pack it around the top of the bearing while pressing it between the inner and outer races and spin the bearing occasionally. Then put a nice coating of grease on the outside of the bearing and it's good to go. I've never had a problem with this.
dogger315
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dogger315 8/24/2014 11:11am
8/24/2014 11:11am
queen of spodes wrote:
Gotta replace my steering stem bearings. Have bearings and a 20 ton press. My question is will a section of PVC pipe be strong enough to...
Gotta replace my steering stem bearings. Have bearings and a 20 ton press. My question is will a section of PVC pipe be strong enough to let me press the bering back down onto the stem?
You don't need to use any kind of pipe to remove or install the bottom steering stem bearing.

I'm going to assume you have the standard press plates with the two different size semi-circular cutouts that
come with most bottle style presses.

Put the two plates together to make the small hole. Slide the bottom seal and bearing down the stem then put
the assembly on the plates with the stem facing toward the ground and the bearing supported by the press
plates. Line the press ram up with the bottom of the steering stem and press until the bearing seats. It's a
good idea to place an adaptor (sized impact socket will do), over the ram to spread the load evenly over the
bottom of the stem and to prevent marring.

To answer mx5471's question, put the bottom triple and stem assembly on your press plates with the stem facing
up this time and the large hole lined up under the steering stem. Again put some kind of protection (socket), over
the stem to protect it and the threads, then press it through. The stem will drop out the bottom freeing up the
bearings and bottom seal.

dogger
jsmx97
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jsmx97 8/29/2014 5:36am
8/29/2014 5:36am
Put the bearing in a toaster oven 250 degrees F it will drop right on...
jsmx97
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jsmx97 8/29/2014 5:37am
8/29/2014 5:37am
Otherwise, you're going to need one of these or something like it

Markee
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Markee 8/29/2014 1:11pm
8/29/2014 1:11pm Edited Date/Time 8/29/2014 1:12pm
What ever you do or use, only press, beat, bang on the INNER race, that photo shows a large pipe that looks to make contact with outer race.

I'm a big fan of proper tools and also using the advantages of cooling and heating of components in interference fits applications before room temperature press and hammer work.

Put the tree in the freezer and the heat the bearing in a oven. I have access to liquid CO2 at work, :D fun stuff.
harescrambled
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harescrambled 8/31/2014 5:01pm
8/31/2014 5:01pm
Markee wrote:
What ever you do or use, only press, beat, bang on the INNER race, that photo shows a large pipe that looks to make contact with...
What ever you do or use, only press, beat, bang on the INNER race, that photo shows a large pipe that looks to make contact with outer race.

I'm a big fan of proper tools and also using the advantages of cooling and heating of components in interference fits applications before room temperature press and hammer work.

Put the tree in the freezer and the heat the bearing in a oven. I have access to liquid CO2 at work, :D fun stuff.
Ya...Co2 fire extinguishers are pretty good for that too...that and chilling your beer Smile

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