spiderbike

I'm trying to replace my bottom bracket after taking no care for it in five years but can't get it off the bike...I have shimano cartridge bottom bracket but just can't get enough tourque to turn the spindle.

I have been turning it away from the front of the bike but have no success, are there any tips for loosening and removing bracket.

newbojeff

Lots of stuff posted here already. Try searching. Also, this thread.

james_swift

Use the right tool. Get yourself a 25" breaker bar. Remove the wheels and place the frame (driveside facing you) on a non-slip surface (carpet) up against a wall for support. With your left foot on the chainstays, hold the socket head (I'm using a Nashbar BB socket) firmly in place with your left hand, and push down on the breaker bar with your right hand clockwise (yes, we're removing the drive-side first). You should hear a crack as the bottom bracket gives way.

So why remove the drive side first? Personally, I do it this way for 2 reasons:

1.) I once had to tackle a rusted/seized BB. I used a 300lb/ft air gun on the non-drive side. No go. After nearly ripping the lockring to shreds with the airgun, I decided to have a go at the drive side. Bingo. Once th drive-side came out, the non-drive side was less reluctant.

2.) Tackling the drive-side first puts you in a position where you can push down with the breaker bar (clockwise to remove), as opposed to pulling up on the non-drive side. You can put all of your weight into the bar in this position.

I really recommend the breaker bar. I have one in my tool kit along with my Nashbar BB socket.

tellyho

I'll second the breaker bar application - my favorite trick. ALso use some PB Blaster. There's the bench vise trick - look it up on the forum. And you may be turning the wrong way - BB drive side loosens clockwise, toward the front of the bike. Good luck.

onbike 1939

The OP talks about the "spindle" and I'm not sure I grasp the problem in that case. Does he really mean the threaded cups?

Retro Grouch 

English (most) bottom brackets have left hand threads on the drive side. That means you have to turn it clockwise to take it off.

phoebeisis

Take retrogrouch's advice and double check the direction you are trying to unscrew it. The right side-where the chainrings- is bass ackwards. It screws off the wrong friggin' way-go clockwise while looking at it to get it off-just like you were screwing in a normal screw, or nut.
It is counter intuitive-you would think that screwing off that direction would make it prone to loosening, but because the ball bearing reverse the direction of the crank/spindle turning, they actually tighten it.
Luck,Charlie
PS-Don't ask why I emphasize this -you can guess!!

Dunwood

There may be a screw that holds a plastic cable guide to the outside of the bottom bracket shell. Sometimes those screws penetrate completely through the bottom bracket shell and onto the surface of the cartridge. It makes it much more difficult to remove the cartridge bb when the screw is in the way.

jbrians

This is a quote from a previous thread on the topic.
I tried everything, as did my local LBS but no go. It was finally the application of heat from an acetylene torch that worked. The BB was cherry red in one small area. Don't try this on an AL frame or you will be looking for a new one.

DieselDan

You may want to try a propane tourch to heat and expand the shell some.

seely

I'd use a breaker bar with caution. The splined lip on Shimano BB's has a tendency to tear off in my experience. Slow, steady pressure with lots of T9/PB Blaster. Sometimes a good fast blow from a hammer will do some good but you do risk tearing that splined interface off.

Garandman

I have the Park bottom bracket tool for the Shimano BB. They suggest using a bolt to hold the tool in the bearing cup if it is difficult to remove. I'm working on the left, non-drive side and turning it counter-clockwise - it's marked with an arrow for "Tighten".

I measured the bolt that holds the crank on and it's about 8mm in diameter and 15 mm long. I measured from the top of the tool to the bottom of the hole in the axle and it's about 55 mm. But I doubt you could thread the bolt in all the way to the bottom of that hole.

Of course, I don't have such a bolt handy. Is there a recommended length?

HillRider

The bolt you need is an M8x1.0 mm. This is a finer thread than the more common M8x1.25 bolts but most good hardware or home supply stores should have them. Certainly an industrial supply shop will.

The length you need is 40 mm although a 50 mm bolt will work if you add a couple of washers to take up the excess length.

Garandman

Great, thanks!
For the fine pitch bolt, for those in the Boston area, Metric Screw and Tool in Wakefield has just about anything you could want. https://www.metricscrew-toolco.com/ But I'll try some industrial hardware stores first.

Doesn't feel like it needs replacing, but out of curiousity I looked up what a Shimano cartridge bottom bracket costs - $25 at Harris Cyclery.

40x14

Autozone, Pep boys, RSStraus, most auto parts store usually have a good supply and selection of bolts for around $3-4/box. Sometimes you can even get high-grade stainless steel bolts, screws, and nuts. I once found a nut for a campy derailleur at autozone when I was in a pinch. They definitely have the M8, industrial supply shop probably has more selection though. Anyone know a good ISS in lower manhattan?

operator

You should post the rest of that thread. This quote is out of context.

Garandman

If it's still a no-go, do folks ever dremel out the BB? If you buy a new Shimano cartridge, it appears they come with new nuts, or?

Moose

Never resort to destructive means of removal before having a professional take a crack at removing it.

geedubbayoo

I second the recommendation for using a long bolt to hold the bottom bracket tool on tightly...there's just no way to do it by hand. If your spindle is hollow you can get a really long one and bolt it to the opposite end...if it's not hollow you'll obviously screw it in where the pedal would go. I bought a couple different length bolts so I'd be ready for different lenght spindles. Then I bought an extra big wrench that would fit the bottom bracket tool and a rubber mallet.

With the bike on the floor I held it in place against a shoulder and carefully whacked the end of the wrench with the mallet. Worked like a charm! And it gave me such a sense of satisfaction b/c the night before I struggled with that thing for an hour with no results.

Get the right tools! I think if you can unscrew the bottom bracket by hand (using a wrench of course) then it probably wasn't fitted tightly enough in the first place.

TO11MTM

An alternative to a long bolt, and actually really useful for how ghetto it is, is the proper threaded axle with a couple locknuts on it.... Usually easier to find than a long bolt.

Josef Taylor

Of course, if it's Italian, (you can tell because the dimensions on the fixed cup are in Metric units) then the fixed cup is right threaded, i.e. lefty-loosey

The Great Stonk

if you going to use a breaker bar, make sure you bolt the tool into the cup (crank bolt, washer and nut) you may have to switch to an open ended spanner.

holding the tool in with your hand just doesnt work, and youll just risk ripping the teeth off the cup...

Garandman

The local hardware store didn't have a 8x1.25 40mm bolt, but HD had a 50. It took 5 5/16" flat washers to space it out.

I measure the OD of the tool and it's 32mm. I have a BMF wrench at work I'm going to try on it. I've been hitting it with penetrant for a week as well.

If that does'nt work, I'm going to try the drive side as suggested above. If all else fails, I'll cut it in a couple of places with the Dremel as I'm planning to replace the cartridge anyway.

Moose

I just don't see how using a dremel is useful in this situation...

fore

Skip the wrench. Clamp the tool in a bench-vise and use the frame as your lever. Just make sure you turn the correct direction.