Need a blade assembly. the flange cracked beneath the rubber gasket and it leaks therefore rendering it useless

Hello, Carla -

For all electric blenders the rubber gasket is placed between the glass or plastic blender container and the rotor with the blades.

The assembly is easy to recall when one realizes the rubber gasket is the seal for keeping liquids leaking out of the blender.

See the image here (it's for a Black and Decker, but the assembly is the same):
http://stainless-steel.us/12-pictures-of-baby-bullet-blender-instructions/black-and-decker-blender-assembly-instructions/

The image here shows the assembly for a Waring blender (different model than yours):
https://www.etundra.com/restaurant-parts/parts-diagrams/waring-bb140-bb150-bb240-bb250-bar-blender-parts/

Best wishes.

I'm no expert but in my experience if it leaking at the bottom then either the jar /carafe has a few chips or cracks around the hole in the bottom that the blade fits through and in that case you need to replace the jar and your blade assembly may still be good and can be moved to a new jar/carafe. Or the blade assembly has come loose a little and need to be tightened or some the washers (usually the rubber ones) have worn out and need to be replaced. There's plenty of explanation here at amazon and else where on how to replace the assembly blade, move it to a new jar and tighten it down, etc. Hope this helps!

Make sure the blade assembly is put together in the correct order. The blade needs to go through the gasket so that the order is pitcher glass, gasket, and metal blade base. Then the final plastic cap threaded onto the pitcher. If the gasket is not between the pitcher and the metal blade assembly, you will have leaks.
Also, check the gasket to be sure it's not cracked and that it doesn't have residue on it.
I hope this helps. If it does, please come back and rate my suggestion!

the part is Black and Decker Blender Base Collar Ring BL5000-11
However these are prone to cracking. I ordered a second after my first cracked, and the second one cracked after just a couple uses.

There is probably a hairline fracture or tiny crack in the blade assembly itself - replace the blade assembly - it will automatically come with a gasket, so you will have an extra.

It could be the gasket, could definitely be that crack in the collar, and even possibly the blade assembly - here is the official website to get all of those parts:
http://www.focuselectrics.com/catalog.cfm?dest=itempg&itemid=4154&linkon=subsection&linkid=112&secid=53

-Tha Mp3 Doctor

The rubber gasket should go between the blades and the jar.

Mine also leaked from day 1. I just read in the manual to first place the bottom and blade assembly on the counter, then seat the gasket around the blade assembly, making sure it is just under the lip of the blade piece (careful, you have to maneuver around the blades). Then place the jar on the assembly and screw in tightly. This worked and I have no more leaks.
This is different than other blenders where you place the gasket on the jar and then attach the bottom. It is a poor design, but after what I paid for it, I am glad to be able to use it and not just trash it.

You can replace the Osterizer "Standard Blade Assembly" (which includes a new rubber gasket) without buying a new and expensive glass jar. See http://www.householdappliance.com/blenderparts.html or one of the other appliance repair parts websites. After 20 years of use, it's time for a new blade and bearing.

I just figured it out. The key is you need to think in terms of keeping the blades and the large washers separate. Here's what you do.
Thread the blade through the glass and use the white rubber gaskets against the glass and the stainless gaskets against the hardware. Then tighten the whole enchilada to the blender with the main nut (that goes on the bottom outside of the blender). Then once that's nice and tight tighten the flange that catches the blender teeth to the remaining portion of the protruding threads. Make sure you use the copper colored gasket first then the stainless washer then the stainless flange. Tighten that real good and you should be good to go.
To check if you've done it right spin the flange. If the blades spin independent of everything else you're good to blend away!