MegaExo Bottom Bracket Removal

alex100a

Hi,

The bearings on the MegaExo bottom bracket that came fitted to my CB are falling apart so its time for a new BB.

The problem I have is that I'm unable to remove the BB! I bought the correct tool ages ago in preparation for this day but I simply can't get them to shift. I started on the non-drive side and applied pressure in the opposite direction to the arrow and ended up damaging the teeth as I had to apply so much pressure. Before I damaged them all, rendering the tool useless, I stopped and thought I'd seek advice.

So any suggestions how to free up an seized MegaExo BB? I've applied GT85 but cant really see this doing very much.

Thanks

Alex

The Rookie

Carbon or alloy frame? You need household ammonia or coca-cola as they dissolve (well the acetic acid in the coke does) the aluminium oxide that's probably seizing them in place, block any drain hole from the BB and poor it into the downtube via the hole into the headtube, attacking it from the outside is a waste of time. Or you can hack a hole in the cross tube between the cups and do it that way.

alex100a

Thanks Rookie.

I'll grab come Coca-Cola tomorrow and give that a go.

Alex

apreading

I had the same issue a few years back - took it to the LBS with the cranks removed and asked if they could help. 2 minutes later it was off. They had a tool with a longer arm which helped I think. Cost was a couple of packs of Jaffa cakes for the shop staff if I remember correctly...!

alex100a

Rookie, coca-cola now in the frame hopefully doing its work! How long would you suggest I leave it?

LBS is my next stop if this fails.

The Rookie

Leave it 24 hours....ammonia is better and only needs an hour or so.

alex100a

Cola does not appear to have worked yet. I'll get some ammonia tomorrow and give that a try.

Alex

rampage7110

Use proper coke not the cheap stuff!

trivial_poursuivant

And don't use Pepsi. No other reason than no one should buy Pepsi