Bottom bracket shell problems help please

My other bike is a mtb have managed to successfully remove worn out bottom bracket. Bought the replacement but can't get it in. First time I have attempted this job. Being a bit of a doofus and not realising what was involved I may have knackered the threads? The new one goes in nicely about half way then gets stuck. Do I need to chase and face? Is there a way I can do that myself without too much expense? It's an aluminium frame.

I have had some problems in the past trying to re-install bottom brackets and them getting stuck half way etc.

Don't force it what ever you do, take it out clean the threads and try again it may take a few attempts just need to make sure the threads are in line. That is if the threads haven't already been damaged.

Did you put plenty of grease on the threads of the shell first? Without any such stuff a thread that size will heat up and bind due to friction, esp. if the shell is aluminium. You only need to face if the BB is not a sealed cartridge type, but you may need to chase the threads if they are rusty, very dirty, or after too many aborted attempts (without grease) fncked! Basically you should be able to screw at least one cup+cartridge (if it's sealed type) most of the way in by hand - if not summat's wrong.

You only need to face if the BB is not a sealed cartridge type

Not true, the only time you need to face a b/b shell is when installing the "new type" (Hollowtech II) external bearing cups. If they don't sit square to the frame, then the bearings will wear excessively.

^ Hang on a mo' what I've said IS true, you've just said the exact same thing but the other way round - read what you quoted from me: "face if the BB is not a sealed cartridge type" is the same as what you're saying: "you need to face a b/b shell is when installing the "new type" (Hollowtech II) external bearing cups"! In actual fact you are 'wrong' because strictly speaking you should ALSO face when using any type of BB where the two bearings are not physically joined together which includes the fancy/traditional NJS type like Sugino 75s etc. with separate races ;-)
p.s. 'sealed cartridge type' means any BB where the two races are joined in one piece, like the Miche, Shimano UN series, modern square taper Campag etc.

^ Hang on a mo' what I've said IS true, you've just said the exact same thing but the other way round - read what you quoted from me: "face if the BB is not a sealed cartridge type" is the same as what you're saying: "you need to face a b/b shell is when installing the "new type" (Hollowtech II) external bearing cups"! In actual fact you are 'wrong' because strictly speaking you should ALSO face when using any type of BB where the two bearings are not physically joined together which includes the fancy/traditional NJS type like Sugino 75s etc. with separate races ;-)
p.s. 'sealed cartridge type' means any BB where the two races are joined in one piece, like the Miche, Shimano UN series, modern square taper Campag etc.

Can we just check what is meant by sealed cartridge unit. To me, sealed and cartridge is talking about bearings that are sealed within a cartridge, like these..

http://www.treefortbikes.com/349_333222341758__6902-Sealed-Cartridge-Bearing.html

As found in Shimano and all current campy, FSA etc external cups.

You are saying the B/B shell should be faced when installing older "traditional type B/B's. I feel their is no need, because the bearings are located within the shell, therefore they are square to the Right hand cup and the left hand cup is either wound in to meet the drive side and flange-less, or has a lockring and sets the bearing preload.

The reason i feel facing is necessary on the modern external cups, is that the bearings are being in effect sandwiched between the crank and the B/B shell. If the shell is not square, it will cause the bearing to wear, as if there were a tight spot.

OK OK, this thread is getting bogged down in a cloud of semantics about what things are called.
Here's what I should have done in the 1st place if I wasn't lazy/didn't think it would end in fisticuffs at dawn:

One piece CARTRIDGE BB (e.g. by Sugino, Shimano UN, Campy Centaur/Chorus)
NO need to face.

Miche CARTRIDGE BB, loose (internal) cups but also one piece and therefore:
NO need to face

Shimano Hollowtech II type OUTBOARD BB (available across whole Tiagra-Dura ranges, this happens to be 105):
Shell MUST BE FACED for optimum performance and bearing life.

Campag OUTBOARD CUPS - the actual bearings are pressed onto the cranks and are indeed sealed cartridge type, but TWO piece i.e. separate.
CAN be installed without facing using Loctite 222 (RTFM if you don't believe me) but FACING highly recommended for performance and longevity.

Sugino 75 NJS type, also what I would call a traditional BB (separate spindle, cups and bearings).
Again, facing not essential but highly recommended for performance and longevity esp. with the more expensive/precision ones (like the 75).

In all cases thread CHASING is always a good thing prior to BB installation if you have access to the tooling, and pretty much essential for outboard bearings.

Shall we call a truce now? ;-)

Absolutely agreed. Very well explained/described. (waves white flag).

Phew! A case of both being fluent but sadly in different languages I think ;-)
Now if only we could solve the middle east conflict too....

Thanks guys glad your tiff got resolved too. In a weird twist of fate I ended up in a really great bike shop getting it chased. I'm staying in the middle of nowhere just now so had given up hope of getting it done till my return to civilisation. However my middle of nowhere was actually pretty close to another middle of nowhere, Clachan of Campsie. It's actually pretty close to Glasgow but you would never guess, tiny wee village with waterfalls etc. 'WheelCraft' is the shop in question it's in a little row of converted houses with a tea shop all very quaint. The owner insisted on making me a coffee and then a fresh pot for me and my family on our return from the waterfall and made me climb a ladder into the loft to see how many rims he stocked. That sounds dodgy I know. Bike junk everywhere whilst they built wheels to classical music. If you're ever up that way just check it out the guy's a real character.

That'll be Big Al at WheelCraft. He's a legend in the Scottish cycling community. He can talk mind.

That'll be Big Al at WheelCraft. He's a legend in the Scottish cycling community. He can talk mind.

No personal experience (my boss (Mick Madgett) trues my wheels), but I have only heard good things of the place, good job there's someone on hand to address your cycle needs :)

Alright, I know this is an old thread, but I always see complaints about people not using the search bar and starting a new thread.
Basically I have an old Reynolds 531 frame, bottom bracket is out, and threads seemed to be in okay condition. But i thought I may as well have the shell re-threaded at lbs.
So I've done that, also have a brand new bottom bracket. But it still isnt screwing in straight - I've cleaned out the threads and lubed it up plenty, but its still screwing in squint.
Any ideas how to fix?

Maybe the lbs crossed the threads they wont have rethreaded it but run a tap through to clean the old threads out maybe they crossed the threads then.If it is buggered a company like Argos remove the old threads completely and sleeve and rethread but that cost about 65quid

Might be the BB itself that is fuckered. Do you have another spare to test this?

Bottom bracket is the right one? as in English not Italian or French just a thought

The bottom bracket and thread is both english...also i'd be surprised if the bottom bracket was damaged as I bought it as new...
Thanks for the help anyway

retro knows his stuff,i bought a NOS fausto coppi frame from him which he had chased and faced the headset and bottom bracket. the 105 italian BB went in like a dream as did the campy record headset.the threads on the bottom bracket are parallel,so plenty of grease and take your time and only use a BB tool when youve wound them in fully by HAND first

retro,its a great ride.pics of built bike are in my album on my profile page

if you've screwed it in any distance at an angle, the threads will be off by that angle. That's what I did, and I had to get bikefix to re-chase the threads. Pain in the bum. Each time you try, it ends up at an angle, that's you cutting new threads!

BBs should go in by hand, all the way, with a bit of tightening up with BB tool at the very end. Plenty of grease is good.