OUR ADVERTISERS

Saturday, October 21, 2006

HOW TO REPAIR A 3 PIECE AND SEALED BOTTOM BRACKET




Well, this is it, welcome to bottom bracket Hell! The lowest, nastiest and filthiest part of your bike, but one of the most important. The bottom bracket holds the axle that not only makes pedal motion possible, but also carries your weight while on the pedals and takes other kinds of too long to mention abuses.

First we'll see how to take a bottom bracket apart and put it back together. Then we'll look at some specifics and do some bottom bracket troubleshooting. It is called a three piece cranck because it has three distinctive parts compared to a one piece crank. There is more then three parts, this moniker refers to the axle and two separate cranks. In comparison with the one piece crank that makes office of both crank and axle.

To take one apart is not that hard, when you know what you are doing and have the right tools. The bottom bracket is one part of your bike that requires a specialty tool and there is no way around that. We are tlaking about the pedal puller. This is the only tool capable of removing pedal cranks. The other tools you'll need are a ratchet with a 14 mm socket, and pair of big pliers and a big flat surface to remove that little plastic cover. I hear you pro mechanics out there screaming and yelling about using pliers to remove any piece of the botton bracket. Yes there are specialty tools for the job and you can buy those at your local bike shop. However, this blog is aimed at people around the world who don't have a ton of money and this way has worked well for me since I began working on bikes. So, with this out of the way, let's proceed.

Removing and repairing a 3 piece bottom bracket


1. Find a big flat something and unscrew the cap off the screw that bolts the crank to the axle. Don't use a small screwdriver, the plastic cover will break inside the crank and you will spend the next hour digging it out.

2. Take your 14 mm socket and ratchet, unscrew the bolt that holds the crank to the axle. Remove the bolt of both cranks(Left and Right). You can squeeze the handle of the ratchet and the crank together like pliers to give you more leverage.

3. Take the puller and screw it's socket inside the threaded hole of the crank. Hold the crank and turn the puller handle clockwise until the crank arm falls off from the axle by itself. Remove both crank arms.

4. Go to the left side and with the pliers firmly held with both of your hands(This is where the pictures differ, I'm taking a picture at the same time.), unscrew the lockring from the bearing cup.


5. Now again firmly with both hands, grab the bearing cup with the pliers and slowly test the resistance. You do not want to slip here since this will definitely strip the thread on that cup. Hold those pliers hard and go slowly, it should get it going within a quarter turn and then you should be able to unscrew it with your fingers. If not, keep on going and be careful. Remove the cup.

6. Remove the axle and bearing crowns from both sides.

7. Remove the right side bearing cup by unscrewing it in a clockwise fashion. The notch are not very wide, so might have to hold the pliers on the cup with one hand and the handles with the other. Go slowly, I've pinched the inside of my hand on a few occasion. Be aware that this cup is often very hard to remove. Again, you can always purchase a specialised wrench just for that purpose. I'm just cheap!

8. Clean and inspect everything. What you are looking for is a clean and even line on the axle and inside the bearing cups. Any pits in that line will damage the bearings and they will eventually self destruct. Replace any parts that need replacing.


9. Regrease everything, the axle, the cups and the bearings. I use regular green axle grease with a touch of white teflon grease. Make sure that everything you've pulled out of that frame is extra clean, including the hole in the frame where it came from. The most minute piece of crap can ruin your repack job.

10. Start by installing the right side bearing cup. Screw it in counterclockwise real tight. Insert the bearings and the axle. Insert the bearings in the left bearing cup and screw on the frame. Screw it until you feel resistance. Test to see if the axle turns freely and tug it up and down to see if there is any play. No play? Turns freely? If the answer is yes to both questions, install the lockring on the left bearing cup.

11. Reinstall the crank arms tightly. I would check them again in a few weeks to be sure. When you think it's tight enough, tighten some more. That's it, you're done.

VARIATIONS

The sealed bottom bracket
The sealed bottom bracket is the same thing but it is in one piece and the bearings are sealed. You need a special ratchet socket to remove it. You cannot repack or adjust it. If it's busted, you have to buy and install a new one. Some like this type of thing, but I don't. I like to be able to fine tune my bottom bracket axle.


Cotter pin crank arm removal
Some older bikes keep the crank arms on the axle with cotter pins jammed between the axle and a hole in the crank arm. It is held together by a nut. An old bike mechanic taught me the secret on how to remove these. Sorry, I had no cotter pin cranks in stock and can't provide you with pictures of this. Guess you'll have to make it with the written word.

1. Set the crank arm at the 6 O'clock position.
2. Unbolt the nut, remove the washer and reinstall the nut with a 2 mm gap between it and the crank arm.
3. With the crank arm still at the 6 O'clock position, give the bolt a solid wack with the help of a good hammer. If it moves inward, you're ok. Repeat this 2 mm at a time until it comes out.

I don't know why, but it works. If you put the crank arm at the 3 or 9 O'clock position to punch out the pin, the cotter pin somehow jams itself and the only way to remove is to drill it out. This method works 90% of the time. If it doesn't come out, your only option is to take a drill to it.

Bottom bracket troubleshooting, or that cracking noise you hear when pedalling.

Ah yes, that annoying cracking noise when applying power to the pedals. This problem comes to my attention often and the tricky part of it is that you have 3 variables to consider to eliminate it.

1. Check the pedals, if their bearings are loose, this could be the source of your problem.
2. Pedals are ok. Alright, check the crank arms one at a time to see if they move sideways. If one oif them moves and not the other, then it's loose and you need to tighten it up. Take note that when a crank arm falls off by itself, the square inside that holds it snug on the axle have rounded off and it will never stay on however hard you tighten it back on. You must change it.
3. Both crank arms move sideways at the same time. The bottom bracket axle is loose. Unscrew the lockring on the left side and adjust the left bearing cup until there is no movement.
4. If the noise still persist, you might have pitting on the axle or cups. This will call for a complete bottom bracket overhaul. But hey! Now you know how to do that. :)

Until next time, ride safe.

Gerry


51 comments:

Alex Tsatsoulis said...

Wow, this is exactly what I've been looking for since I began overhauling my old bike. Thanks for all the info and especially the pictures! Keep up the great blog!

Luke Czirok said...

This blog has helped me alot. Thanks, however when i took off my crank arms, i had a one piece internal bracket. Also, i needed a second special tool to remove this, because it was just a ribbed circle - thingy. I cannot really describe this to you, but it was like a ring with a ribbed edge.

It just suprised me.

Thanks alot,

Luke

Anonymous said...

Merci, Gerry.

I am building a bicycle. I need to remove a crank from an old bicycle to use on the new bicycle. You have made that possible. Thank you. I will refer to your site often for instructions.

Merci encore,
Alain

George Rutherford said...

I can't believe how helpful you've been. A couple days ago I was riding my old Raleigh and my left pedal fell off. It was a broken axle. I looked around town today and haven't found a replacement yet, but after reading your blog I now have hope. At least I think I know what questions to ask now. Thanks.

Anonymous said...

hi mate what else can you use if yu havent got a puller

Gerry Lauzon said...

I guess the only other option would be to find a big bolt that could be screwed in there.

Gerry :)

Sy said...

Hey Gerry this is Sy from Downunder thanks a million for your info its been VERY helpful. For the first time tonight I removed some cranks which gave me a real thrill. Do u have some info on your site about building a single-speed?

Gerry Lauzon said...

Happy to hear you enjoy the site Sy. If you are talking about a fixed gear bike, I've never built one myself, so I don't have any info to share. Just Google fixie bike and you will find tons of info out there. Fixed gear bikes are becoming quite the rage. I guess it's a return to the purest form of cycling.

Gerry :)

Anonymous said...

Gerry

This week I found a dual suspension frame which had been thrown away and I have been transferring everything from my cheapo bike across to the new frame. I couldn't move over the bottom brackets as they were different sizes and your article has been a great help. I now have a new bracket and just need to adust the gears and brakes.

My £50 bike is now going to be a £200 bike, thanks to your really straightforward, easy to follow articles.

Gerry Lauzon said...

I'm always happy when I hear that another bike was saved from the scrap pile. Glad I could help. Enjoy your new ride.

Gerry :)

Anonymous said...

my specilized dosent have rings on it and it dosent look the same what should i do

Gerry Lauzon said...

It sounds like you have a sealed bottom bracket. Click on the first image to enlarge it, it has the details for that type of BB.

Gerry

Anonymous said...

Hi Gerry. I am from singapre and am a frequent biker. I have an 8 year old MTB that just sheared its left axel one day as I was getting onto it to pedal upslope. The left pedal dropped out and I was shocked to see that the left axel that held the pedal was bent and there was a tear on the metal. I was wondering if a bent and partially sheared axel from the left side can be removed from the bottom bracket. Is it the same procedure as mentioned above or do I need additonal tools to remove it for replacement? Thanks

Gerry Lauzon said...

It's the same procedure. From what you told me, you'll have to replace the entire pedal axle. This is the very first time I hear of such a problem. Either you have very strong legs or your axle was made with very weak steel.

Good luck.

Gerry :)

Anonymous said...

Ic. Thanks Gerry. Come to think of it. About a yr ago, the left pedal became a tad wobbly. checked to see if the bolt that secured the peddal to the axel was loose but it was not the case till now.... Anyway the sheared axel was of a male type. I found an abandonded MTB bike frame without its wheels and all except the pedals and the axel in its bottom bracket but the bike uses a female type to secure the pedals to the axel using a male screw. Can it be canabalised to be fitted onto my bike in question? are all MTB BB the same diameter? Thanks :)

Gerry Lauzon said...

The answer is yes, make sure that the axle from the junk bike is the same size as the one you have. You can get away with a few mm difference, it doesn't have to be exactly the same. It should at least be in the ballpark.

Good luck again.

Gerry :)

fatboy said...

what do you if you dont have the pulling tool

Gerry Lauzon said...

You buy one. There is just no way around this that I know of. Sorry.

Gerry

Anonymous said...

Your blog is absolutely great. I am in the process of upgrading my Bianchi and need to know if I can replace my 3 piece BB with a cartridge BB. My BB is a Campy Mirage and stamped with "1370x24 TPI Left Lock 70MM". Does this tell me what size I need?

Thanks,

Jon

Gerry Lauzon said...

Yes Jon, any 3 piece BB can be replaced by a cartridge. When you go get that new one, bring your old BB with you to make sure that you have the right size. That is the best way I know.

And thank you for your comments.

Gerry :)

Anonymous said...

Hi Gerry,

As ever, I was trying something new at the weekend (i.e. something I haven;t done before) so naturally came running to your website for advice. On my daily commuting road bike I wanted to replace my existing 52/42 chainring/crank set with a 50/34 one which I thought would be beter suited to helping me negotiate the southern French hills. This led me to two questions:

1. Reading your 'bottom bracket' blog, I think I need more help with your step 3; namely, what the "puller" is and how to use it. It's probably a lot simpler than I think, but your blog zooms over it somewhat. I have a sealed BB and the cranks are held on by screws that are loosened with an alum key, but on removing these retainers, either side, I couldn't get the damned things to budge.

2. Currently, I have a short cage rear derailleur (Shimano Sora, 8 speed). I imagine that switching from 52/42 to 50/34 I'll need to go with a long cage one now?

Hope you can help me, Gerry (and not for the first time!).

Best wishes,
Neil

Gerry Lauzon said...

Hello Neil, I have no clue of what you are talking about concerning your crank arms. Either I'm a complete idiot or you have some new kind of set up which I haven't come across yet. Please do send me pictures of it at : xddorox ( at ) gmail.com so I can look it over and better help you out. As for the long cage derailleur, 34 teeth is granny gear country and it would definitely help. Try it with the short cage first if your not sure about buying a new derailleur.

Wrtie me!

Gerry :)

Anonymous said...

Thanks for the speedy response, Gerry.

No, you're not being stupid, and nor do I have some wacky set-up. It's all down to my not being able to explain the situation properly (having done it after midnight my time before going to bed!). OK, I'll try to take some pictures today. (I would make a quick phone video, but for some reason my stupid phone won't record videos longer than 8 seconds!)

In the meantime, I'll try a better 'wordy' explanation ....

My bike (a one-year old economy end Decathlon road/sport bike) has a standard sealed BB. As depicted in your picture at the top of the blog for a sealed BB, my axle (or is that spindle?) has a square cross-section and each end has a female screw thread going into it. The crank on each side is slid on to the axle and is held in place by a 'screw' that screws into the end of the axle. The head of each screw has a large alum key opening.

So, when trying to remove my old cranks/chainrings, I unscrewed the 'screws' through the pivots of each crank to reveal the ends of the axles. However, common sense told me that I should now be able to simply 'wiggle' and slide the cranks off each side to leave the bare axle ends ready to install my new cranks/chainrings. But I just couldn't get the crank arms to budge, not even a fraction of a millimetre. I tried pulling, wriggling, hammering, levering, etc. No joy. They were on fast! Then I went to your blog (again) and read it more carefully and noticed that you had a step that I'd missed out - the one involving the "puller". And that's where my mystery lies. I have no clue what the puller is, nor what I'm supposed to be doing with it.

Take care, and hopefully 'speak' again soon.

Neil

Anonymous said...

HEY, GERRY!

I'VE CRACKED IT!!!! (As in, I've worked it out, not that I've cracked my bottom bracket or anything!)

Since I suspected my problem was the missing step involving 'the puller', I did a quick search using your bike-specific search engine and found a page on Sheldon Brown's site about it. That led me to an odd piece of metal I'd had in my bike tool kit that I'd never used (i.e. the one remaining item that's NOT covered in sticky black finger marks). A few minutes of thinking it through followed by another few minutes putting theory into practice and .... BING! My bike is now sporting (rather proudly) a new set of Stronglight chainrings and cranks! Actually, the most painful part of the process was re-adjusting the cable tension on the front derailleur to cope with the taller gap between rings. The use of 'the puller' itself was a piece of piss (as we say in the UK). Definitely a case of mysterious when you don't know, simple when you do.

And as for the rear derailleur issue (namely, whether or not I needed to get a long cage one), a slight adjustment to the chain length (adding a couple of links) was enough to give me the full range of gear combinations with the existing short cage rear deraillueur doing its job nicely in all cases.

Thanks, Gerry. Sometimes just airing a problem helps you to think about it in a more enlightened fashion!

Best wishes,
Neil

P.S. Congratulations on your continued 'non-smoking' status. How's it going?

Anonymous said...

> ... a slight adjustment to the chain
> length (adding a couple of links) ...

Ooops. That should have been REMOVING a couple of links.

OK, I'll shut up now! ;-)

Neil

Gerry Lauzon said...

Neil, ok now I understand. The puller has 2 pieces, one that screws into your crankarm and one that screws into itself. You hold the outside socket and turn the handle of the tool counter clockwise almost all the way out. You then screw the outside socket of the tool all the way into the crank arm. Now you turn the tool handle clockwise and this will push a pin against your axle and will pull the crank arm out. You absolutely need this tool, no hands or fiddling with regular hand tools will do the job.

I guess I found my next video subject!

Gerry :)

Anonymous said...

Hi Gerry,

A bit late for me as I managed to figure it out, but I think a video on the use of the crank puller/extractor would be fantastic and prevent idiots like me spending a weekend trying to hammer and lever their crank arms off!

Have fun!
Neil

Anonymous said...

i have a 1 piece bottom bracket wich isnt broke as in it dont move but has aload of dirt and grit in how do i clean it up and relube it
is there a cheap way of doing it the tool is like £14 for a little bit of metal
thanks

Gerry Lauzon said...

Happy to hear it Neil. As for the reader with the BB, I'm guessing you are talking about a sealed bottom bracket. There is no possibility of doing maintenance on these. Either they work or they don't, in which case you have to replace it. There is no way around getting that tool, nothing else will work to remove the BB unless you want to mess things up and waste a ton of time with a hammer and a flat screwdriver (with no guarantee that it will actually work).

Gerry :)

Anonymous said...

Wow. the most simple, helpful, clear site i've found so far! Thank you so much!! The bottom bracket how-to just saved me $50!

Anonymous said...

hi,
my name is henri. i looked up my problem on yahoo but i couldnt find a solution to my problem. i came across ur posts on www.howtofixbikes.ca but still cant find a solution so i thought my last try would be to ask you. In your post "how to fix a three piece and sealed bottom bracket" u said "The bottom bracket holds the axle that not only makes pedal motion possible, but also carries your weight while on the pedals and takes other kinds of too long to mention abuses". My problem would be best described as when i stand up on the pedals or im pedaling up hill, it slips and dosent support the weight. if i pedal lightly its fine but when i try to pedal harder it continues to slip. please let me know if u have a solution for me. thank you for your time and have a nice day.
henringuyen36@gmail.com

Anonymous said...

Henri, it sounds like your drive train is getting worn. That includes a chain that is "stretched" and sprockets whose teeth have been worn down into a sawtooth shape. Your best bet is probably to replace your whole drive train, but you might get away with just a new chain. I highly recommend Sheldon Brown's article: http://www.sheldonbrown.com/chains.html

Gerry Lauzon said...

Henri's problem was answered via email. I only now realize that it didn't benefit every one by doing so. Thanks for that great answer anonymous.

Gerry :)

Anonymous said...

Great site. Since you need a crank puller to get the crankset out, is there a special tool to install? I read on another site that you are suppose to screw in a bolt into the tapered spindle but the BB on my bike doesn't have threads for a bolt. Instead it has threads for a nut like the one in pictures 6-8. And I cannot get the crankset in enough for a decent chainline. Is this a compatibility issue?

Thanks.

Gerry Lauzon said...

All you need to re-install the cranks is a 14mm ratchet socket and ratchet wrench. The cranks will go in a bit more once they are tightened down. You'll have to do that in order to estimate your chainline properly. If it isn't aligned, you might have to go with a smaller axle( I'm talking width here).

Gerry :)

Anonymous said...

the lockring is really tight and my tool is slipping when trying to take it off...any suggestions?

Thanks

Gerry Lauzon said...

It ain't pretty, but try wacking it with a hammer and a flat screwdriver.

Gerry

Anonymous said...

got it thanks :D...i wish i could post a picture...when i pulled out the axle..the bearing cartridge on the drive side looked like it was exploded and the bearings were rolling around free in the bb housing...that explains the problems i was having..haha

Gerry Lauzon said...

Chances are that the bearing race on the axle is shot. You'll probably have to replace it if you want your new bearings to survive.

Gerry

Anonymous said...

Hi Gerry,
I ride a 26 inch diamond back mountain bike. While riding it work the other day the removable rear axel pin that slides throught the rear wheel and gear set cracked in half. I purchased a replacement pin and when I tried to install it the back wheel would rotate for a moment and tighten up until neither the pedals or for that matter, even my hands could make it budge. Further more after a few of these rotations the pin was almost so tightly screwed on the frame that I could barely remove it. It is one of those "open, close" metal tab locking axel pins. Any suggestions on what could be wrong?

Gerald said...

Sounds like the axle is broken inside the hub.

Gerry

Scott, Sask said...

Hi,
recently I have been experiencing a kind of "slipping" action while pedalling, so I took apart the bottom bracket and found that one bearing cage is damaged. After some searching online I've found that some people simply replace caged ball bearings in favour of using loose ones and now I'm wondering, would it be possible for me to take these nine ball bearings, throw away the cage and just use them loose? Or would this result in some kind of damage to my bike?
Thanks,
Scott

Gerald said...

You would need to add a bearing ball or two if you remove the cage. The cage is simply there to hold the bearing balls in place.

Gerry :)

Anonymous said...

I've got an old Pegasus 10 speed. The crank on one side has some play, front and back. I tried the simple fix of tightening it up, but it didn't help. Any suggestions.

Gerald said...

The seat of the crank that goes into the axle is now rounded out and there is no amount of torque that will keep it there. You will have to replace that crank arm. When you do, tighten it up again after 2 weeks.

Gerry :)

Donald said...

Thanks this helped more than any other site.The pics and step by step i could understand.

Overmyhead said...

People like you help keep the world on track. Thanks for taking your time and sharing your knowledge. You've certainly helped me out!

Gerry Lauzon said...

And thank you for making my day.

Gerry :)

Anonymous said...

There is a special lockring tool that will prevent damaging the lockring with pliers.
Also, A sealed bearing bottom bracket can easily be rebuilt, bearings cleaned and repacked or replaced. There are 6 parts to a sealed bottom bracket. The left removable threaded cap. The right flanged threaded cap, 2 sealed bearings, a hollow tube body between the two bearings and the spindle. They are pressed together and can be seperated by tapping on the righthand end of the spindle with a hammer. First hold the right cap and tap the spindle out, then hold the body and tap the spindle out of the right bearing. Once apart the seals can be carefully pried out with a razor blade and the bearings cleaned and repacked, then replace the seals.

Anonymous said...

This is all good , but not when one gets to picture (9), this is were you must get the proper tool or make one. If you use the big pliers, it will only damage the threads!!!!Trust me, you will get it off, but you might not get it "back on".Dont chance it!!!

Gerry Lauzon said...

Yes you do have to be careful since those pliers are not made for that job. I have done hundreds of time this way and never had problem but I am careful and too cheap to buy the prorer tool.

Gerry :)