Loctite 609 - simple question

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alcatraz
Posts: 1048
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Hi WWs

To fix a creaky trek bottom bracket I got some loctite 609 that is supposed to be a bit more permanent than loctite 641 that I have been using previously.

What amazed me is how low the viscosity is of this 609 I received. The 641 is thicker almost like ketchup but the 609 is more like cream/fat milk.

It still smells like loctite. Yummy :lol: ...and it's green like loctite retaining compound.

Is it right you think? I'm afraid it might be wrong somehow. It could be right because I remember superglue is very low viscosity and it doesn't necessarily mean it's less strong.

/a

by Weenie


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Calnago
Posts: 6386
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

It’s the right stuff... but not for a BB90 application. it’s for smaller gaps than what you have. A Trek BB90 is slip fit, not anywhere close to an interference pressfit. You should exhaust all other options before using a retaining compound in a BB90 setup because when you want to remove the bearings you really only have access to the inner race and you could possibly pound that race out along with the actual ballbearings, but leave the outer edge behind. Are the bearings new and still creaking? You might want to get in touch with Trek as there are some slightly oversized bearings for such situations. You’re sure it’s the interface between the outer bearing race and the shell? Preload is correct and all that?
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

alcatraz
Posts: 1048
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Thank you very much.

I'm following the suggestion in this guide.

https://www.bbinfinite.com/blogs/news/t ... s-solved-1

Because I'm not jumping to the strongest "adhesive" right away and moving gradually from light/medium to stronger (and I don't use ceramic bearings) I'm hoping I just get enough retension to stop the creaking but not to permanently lock the bearings in place. Removing the bearings that were mounted with loctite 641 was an easy task. I did it once on the same frame.

It's a gxp crank but it's preloaded by a wavy washer on the right side because I'm using an alloy 24/22 reducer sleeve on the left side that doesn't allow for the left bearing to be clamped tight like on normal gxp bb's. (I'm told on normal gxp the wavy washer only keeps the right dust cover in place). I've scratched my head a few times to try and achieve the left bearing becoming clamped by the crank but I can't get the sleeve in any suitable position to do that.

/a

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Calnago
Posts: 6386
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

That link is pretty much what I was saying. They recommend Loctite 638 for slipfit and loctite 609 for pressfit. Even though it is advisable to use a press for installing bearings into a BB90 bottom bracket, it is not really a pressfit. The press does however help keep things aligned and makes it easier to ensure the bearings get fully seated in the shell. So, 638 is what you want... I’ve used that for the Campy B.B. kit for Trek BB90 (the seal seats). You would also be advised to use a primer (Loctite 7649) as you’re trying to create a bond with the carbon. None of these retaining compounds are permanent but like I said, the bond can be strong enough that there is the potential for knocking out just the inner race (along with the ball bearings) upon removal, leaving the outer race still in the shell. They don’t mention that in their video. (Why spoil things). But what they do say about just applying it sparingly to the outer surface is correct... otherwise you can squish it behind and back into the bearing itself when you’re pressing it in. And trust me; that makes a supreme mess of your bearings if it gets inside. So be careful and good luck. Might still want to check with Trek for the slightly oversized bearings if your BBshell seems kind of shot.
Good luck.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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ms6073
Posts: 2476
Joined: Fri Jul 23, 2004 8:24 pm
Location: Houston, Texas

by ms6073

Calnago wrote:
Wed May 09, 2018 5:25 am
None of these retaining compounds are permanent but like I said, the bond can be strong enough that there is the potential for knocking out just the inner race (along with the ball bearings) upon removal, leaving the outer race still in the shell.
Heed that bit, especially when dealing with an all carbon bottom bracket shell as I have found Loctite 609 will form a very good bond.
Michael - The Anaerobic Threshold is neither...

alcatraz
Posts: 1048
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Well I did it and it could have been a mistake. I will find out in a few days if the creaking stopped.

I noticed that some residual 609 just in a few seconds glued the bearing outer race edge to the press quite well, and this stuff has a 24h curing time. Wow.

I'm afraid that I won't be able to just tap them out later and have to create a kind of press/pull jig.

I got some deep groove skf bearings in there and not some delicate ceramic stuff. I don't think it will separate. I'm more afraid I'm going to damage the shell.

At least the big/heavy owner is happy that the bottom bracket is more secure.

/a

by Weenie


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