Help removing pivot bearings

jimothy78

Hi all, I'm currently working through my frame (Cube AMS 130), replacing the bearings.

I've managed to remove all the others using a selection of drifts and clamps, but the bearings for the pivot between the rocker link and front triangle have me slightly worried.

The bearings in question are housed in a cylindrical tube fixed perpendicular to the seattube:


There appears to be 4 bearings (a pair on each side), with a spacer in-between (which I take to be the one shown in the upper right of this picture:


This spacer is internally threaded to accept the bolts that hold the pivot together, and also appears to have an internal wall in the centre with a hex-key cutout (which I presume is for holding the spacer when you tighten the first bolt, to stop it spinning).

Now my worry is this - I can't find any instructions for removing these bearings, and can only think of two ways of doing it - do I attempt to push one pair of bearings out from inside, using the internal wall of the spacer to brace a narrow drift against; or do I use a wider drift, brace it against the outer bearing on one side and try to push the opposite bearing out (the latter option seems less likely to damage the spacer, but will require a lot more force, as I'll be effectively pushing 4 bearings through a tube simultaneously.

What would you do?

nicklouse

Ok the bolts for this are the Middle two on the left? And the spacer to right. 4 bearings. What else?

jimothy78

nicklouse wrote:

Ok the bolts for this are the Middle two on the left? And the spacer to right. 4 bearings. What else?

You're right about which bolts, yes. The central tube part appears to be filled by the spacer (top right) and four bearings, then the silver washers go on the outside of the bearings, between them and the rocker link, then the bolts screw through to secure it all.

nicklouse

So in effect the whole lot is floating.
That is to say you should be able to press everything out in one go.

Put an Allen key in and check it rotates and is not seized. I am guessing position is controlled in another pivot.

jimothy78

nicklouse wrote:

So in effect the whole lot is floating.
That is to say you should be able to press everything out in one go.

Yes, as far as I can ascertain, and given the way the bearings are mounted, when the suspension is compressed, the link, bolts, washers, inner bearing races and even the spacer must all rotate together.

Put an Allen key in and check it rotates and is not seized.

Yeah, it spins freely - at first when I noticed the hex shaped hole, I thought it might be some sort of self-extracting insert to help with bearing removal, but it just spins and spins on the spot - there's no resistance, and no lateral movement at all.

I am guessing position is controlled in another pivot.

Not sure what you mean by this?

nicklouse

There is nothing stopping the whole thing moving in or out of the frame.

Just a thought. Check the diameter of the sleeve/spacer compared to the bearings. It could be that there is a shoulder in there providing the location. If it seems there is a difference then you should be able to press on the spacer to move out two bearings. And then knock the other two out from the other side.

jimothy78

nicklouse wrote:

There is nothing stopping the whole thing moving in or out of the frame.

Ah, that's what I'm worried about - that drawing is just what I THINK is going on in there! If I'm wrong, and there's something holding the spacer in place in the frame, then I could be in trouble :shock:

Just a thought. Check the diameter of the sleeve/spacer compared to the bearings.....

Can't until I get it out - I haven't bought the rebuild kit in that picture, just the individual bearings - hence why I'm worried about damaging the spacer.

One other thought - I can just about see a little shoulder on the inner edge of the bearings through the hole in the spacer - I'm wondering if the safest way to proceed would be to see if I can get purchase for a small flat-head screwdriver in there and knock the bearings out directly - then if I'm right, the spacer should slide out once the bearings are out the way, and if I'm wrong I won't have totaled something finding out :oops:

Guernsey Donkey

Looking at the picture of the repair kit the space looks to be a narrower diameter than the bearings so I would suggest that the best solution would be to use a piece of pipe that is a slightly larger diameter than the bearings and a bolt that will fit the spacer and with some washers under the bolt head use the space to pull the bearings out.

Do i get the prize for the longest sentence? ;-)

nicklouse

jimothy78 wrote:

nicklouse wrote:

There is nothing stopping the whole thing moving in or out of the frame.

Ah, that's what I'm worried about - that drawing is just what I THINK is going on in there! If I'm wrong, and there's something holding the spacer in place in the frame, then I could be in trouble :shock:

Just a thought. Check the diameter of the sleeve/spacer compared to the bearings.....

Can't until I get it out - I haven't bought the rebuild kit in that picture, just the individual bearings - hence why I'm worried about damaging the spacer.

One other thought - I can just about see a little shoulder on the inner edge of the bearings through the hole in the spacer - I'm wondering if the safest way to proceed would be to see if I can get purchase for a small flat-head screwdriver in there and knock the bearings out directly - then if I'm right, the spacer should slide out once the bearings are out the way, and if I'm wrong I won't have totaled something finding out :oops:

Ah in that case press from the spacer outwards. Should push out the spacer and two bearings. Then knock the other two out.

Herdwick

you need a sliding hammer bearing puller to remove those bearings, it's a special tool this http://www.enduroforkseals.com/id197.html

or go ghetto puller with this
http://ausbuells.informe.com/forum/buel ... 56-15.html

or this

http://www.instructables.com/id/2-Motor ... ng-Puller/
if you are not sure of what you are doing don't risk your frames well being, go to a shop instead!!!

Herdwick

and don't use a flat head screw driver, there is a chance to knock the bearing on one side and damege the aluminium case/frame or if you're lucky enough get a busted knuckle,

I never saw a double bearing before in any automotive/machine ever and don't see the reason to,

you can always use a wider bearing, or a spacer to match the width but never a double bearing.

the groove I see from the picture it may be the spacer further in or the groove that the puller secures in the bearing.

jimothy78

Herdwick wrote:

or go ghetto puller with this
http://ausbuells.informe.com/forum/buel ... 56-15.html

That's a nice idea - might try that.

Herdwick wrote:

I never saw a double bearing before in any automotive/machine ever and don't see the reason to, you can always use a wider bearing, or a spacer to match the width but never a double bearing.

Hope freehubs use a double bearing at one end, and this same frame uses double bearing in some of the other pivots (the ones in the chainstays, near the dropouts - I searched online to see if I could find a single bearing the same size, but no luck). Finally, the bearing kit definitely shows 4 of the bearing involved, so I'm absolutely certain that that's what I'm looking at.

nicklouse

Just be careful of the thread and the spacer.

Herdwick

jimothy78 wrote:

Hope freehubs use a double bearing at one end, and this same frame uses double bearing in some of the other pivots (the ones in the chainstays, near the dropouts - I searched online to see if I could find a single bearing the same size, but no luck). Finally, the bearing kit definitely shows 4 of the bearing involved, so I'm absolutely certain that that's what I'm looking at.

Ahhh fair enough, didn't know that!!!
take your chances, and as nicklouse said, take care not to bash any threads or the spacer!!!

and post some pics when you're done, and some of the double bearings on the pivots if you can, I d'like to see how it works