[CR]Stuck Adjustable BB Cup

(Example: Framebuilders:Brian Baylis)

From: <emeneff@earthlink.net>
To: <classicrendezvous@bikelist.org>
Date: Tue, 30 Sep 2008 11:14:49 -0700
reply-type=original
Subject: [CR]Stuck Adjustable BB Cup

I've faced this a number of times through the years. Had one recently just like you described - an otherwise good condition steel Ibis mtn.frame where the fixed-cup came out fine, but the adjustable cup wouldn't budge despite all manner of tools AND curses from numerous languages. I knew it was bad when I ran out of profanities along with spare pin-tool pins.

I soaked profusely with penetrant oils - didn't do a thing except make the pin tool jump out even more. If there is some sort of threadlock / sealant in the thread gap you will NOT get penetrant oil in there to do its job.

I was about to apply a propane torch lightly to the cup in order to soften the Loctite I suspected was in there, but I decided to make one last room-temperature attempt with an old universal-style fixed-cup tool that works by friction to grip the cup. With two wrenches working together it finally did the trick and broke the stubborn cup free. I weigh 185 lb.s and had to STAND on the wrenches and BOUNCE to get the thing to move. http://sheldonbrown.com/tooltips/bbcups.html

It was as I thought - a thick coat of blue Loctite was still in the threads. It took a lot of effort to turn even after it broke free.

If you apply the propane torch to just the cup, oftentimes you can limit the paint damage and discoloration. Most grades of Loctite soften well at 180-250 degrees fahrenheit - so the items don't need to get red hot ! They don't even show any color at all, and there is absolutely NO effect on heat-treatment or tempering at those low temperatures.

You can also limit or eliminate paint damage by wrapping the adjacent areas with wet wrags - they protect amazingly well.

Also - do it OUTSIDE as there often is a pretty unpleasant stink released from any burning oil/grease/ penetrant. Spouses rarely share the joy of your mechanical triumphs when faced with a stinky house / garage.

When used properly and in the right grade for the job, Loctite can be a great blessing in the sloppy threads and vibration-filled world of bicycles. But it can bring utter misery when it gets applied to the wrong places with the higher-strength grades.

Good Luck!
Mike Fabian
San Francisco, CA