GravenTim

I am trying to untighten a bottom bracket.
My question is: how do I get this leftcup unscrewed?

I have attached a picture of the bottom bracket.

Thank You in advance

Kind regards

dabac

The outer ring with the notches is a lockring. The correct tool is a hook wrench. But usually it'll come out with some help of a hammer and a drift punch. Or sacrificial flat blade screw driver.
Looks like someone has done that earlier.


It should loosen counter-clockwise.
Some penetrating oil is recommended when things look like that.
Then an adjustable wrench can be used to get the cup out.


With things looking like that I'd try to rig something to keep the wrench from slipping. Wooden block with a hole, threaded over the bb axle, held in Place by the crank nut. Something like that.
Should also back out CCW

u235

Like mentioned, spray that thing down with some penetrating fluid. I personally like PB "blaster" brand but any brand is better than none. Tap it with a hammer all around to assist in the penetrating action and to break up some of the corrosion. If it still does not come off, spray and tap some more and try in a few hours. The next step is applying heat but hopefully that won't be needed

SkyDog75

Adding 2 cents to dabac's excellent advice...

Because of the rust and the chewed up lockring, I'd consider replacing that bottom bracket if you plan to keep the bike long-term. It won't be any more fun the next time you have to work on it.

If and when you get around to the other side of the bike, be aware that you'll need to turn the bottom bracket cup clockwise to remove. The fixed cup is left-hand threaded.

GravenTim

Thank You for the advice

These BB are the hardest to remove. (according to my experience with other bb)
I will use WD40 and then a hammer...

The other side is already removed.

ramzilla

Don't get in a big hurry. That thing needs to soak in penetrating oil overnight. It's already chewed up. So, what the heck. Put a pipe wrench on it and git er dun.

CliffordK

You can also ignore the lock ring and remove the BB cup.

I have a couple of really big adjustable wrenches that can grab both halves of the BB. Or, the official tool will work. I like to add some kind of spacers to it until I can tighten down the crank spindle nut to keep the wrench from slipping off the BB.

As far as lockring wrenches, there are some that are better than hook wrenches, but most are designed for 3 or 6 notches. It is hard to tell, but it looks like the one above has 4 notches which is odd.

dedhed

If the other side is already removed the spindle should come out. When you pull the spindle note if it is symmetrical with respect to length. If not, note which side is the longer side as this will make a difference as to what BB length you need should you replace it with a cartridge one. Cartridge ones are usually symmetrical.


With the spindle removed you can bolt a wrench down with some washers so it doesn't slip off.

speedy25

Pipe wrench is good advice to get those rusty parts apart.

As noted previously- Whats left inside will most likely need to be replaced.

-SP

JohnDThompson 

Remove the lockring first, either with a hook spanner or and hammer and punch (looks like a hammer and punch was used in the past).

If it's not too tight, a 16mm cone wrench will work on the cup. Otherwise, the Park Tool HCW-11 will allow more torque:



HCW-11 Adjustable Cup Wrench | Park Tool

Bill Kapaun

WD 40 isn't penetrating oil. Get the real stuff.
Since the other side is out, you should be able to use a stout piece of flat bar for a wrench, since the spindle can be removed.

GravenTim

Thank You for all the advisory.

I will try a wrench on the cup after getting the lockring off.

The bb is soaking in penetrating oil at the moment.
Then I'll have a go at removing the damn thing.

Randybb

I always have a 30" pipe wrench lying around as a last resort. It grips onto anything and it's massive. you can always slide a pipe over the handle of a wrench to get more leverage.

Maybe this video will give you some ideas?

GravenTim

I've gotten the bb off.
It was easier than expected.
I used a big adjustable wrench to get the cup off and the lockring started coming off too.

Thanks again for all the help.

JohnDThompson 

Good enough. Was there any particular reason why you didn't take the lockring off first? Unless it's seized onto the cup with rust, removing the lockring first makes it much easier to remove the cup.

GravenTim

The lockring was indeed seized with rust...