Bike as not shifting properly so I brought it in to be looked at and was told the b-tension screw is bent. They did not have a replacement but wanted to sell me a whole new rear deraileur. Anyone know where you can get a replacement b-tension screw for a dura ace 10 rear deraileur online?
that may not be something you can find online…unless someone is parting out a rear derailleur. However, your LBS should be able to order you the part direct from shimano. If they won’t, then go to a shop that will. It’s a $2 part that shimano has in stock.
I don’t know where you can get one online. I’d guess that we could get you one if you let me know the generation of derailleur.
http://www.fastenersuperstore.com/index2.cfm
we have a store in town like this. The would have somthing .
Go to Pro Bolt and order the bolt you need.
For a DA 7800 rear the b-tension screw is an M4x12mm Button head… and you can get whatever color you want 
ACE hardware is great for this stuff. It’s a simple M4 screw, probably $0.15.
You can probably find it from one of the replies already… but there is a place called Petra Cycles out of the UK that does alot of Shimano replacement parts online. I needed a spoke for a DA wheel and they were my only option.
-Physiojoe
M4 x 12 is a standard Speedplay cleat screw. PM me and I’ll put one in the mail to you.
Bernie
Just sent you a PM - thanks so much.
And thanks to everyone who replied. Said it before and will say it again - ST rocks.