no that bracket wont budge in and out. It will pivot though. It is bolted on one side with an allen bolt. I think that is why it wont move in and out. The other side has a bolt that bolts into the bracket and seems to float in a rubber boot inside the caliper, it is visible in the pictures

 

Remove the bracket pull the pins and grease them with high temp caliper pin grease. Before you grease them you should use some 600 grit sandpaper or steelwool and remove all the gunk off the pins. Part number 6 & 8 in the link below.
2003 Suzuki LTZ400K3 Parts, 2003 Suzuki LTZ400K3 OEM Parts - BikeBandit.com

Here's a link to an online manual. Yes its for a dvx400 but its the same thing just different plastic.
"K&T Parts House Lawn Mower Parts and Chain Saw & Trimmer Parts"

 

pin # 8 is stripped. I guess the allen key I had wasnt that good and it stripped. I am thinking of just removing the caliper and taking it to a shop now

front brakes were a snap. also did my sons raptor 80 w/o a hitch. arrghhh

 

I've got a spare rear caliper somewhere with the pins. I'll have to look but I'm sure we can make a deal if you want it. I'll take pics of it and you just let me know what you want to pay for it. I don't have the mounting bracket since I'm using it. I have a bigger aftermarket caliper on mine so no need for the stock one.

 

well i would still need to get the bracket off mine. then i just need the pin. i'll let you know

how do i remove the brake line and prevent all the fluid from draining out? can i pinch it?