I've developed a leak somewhere in the brake system but unfortunately I didnt check my reservoir level frequently so have no idea if the leak is a gusher or a trickle so im attempting to flush the system through and keep a careful eye on the levels.

Its a '71 type 3, front disks, rear drums.

Im having troubles bleeding the rear brakes. I've done the front calipers ok - does it matter if i bleed these before doing the rear wheels? Anyway, it seems one of the rear bleed nuts is leaking air back in even though i only loosened it a fraction, so using a tube into a jar of fluid isnt working. Is there any way to get around this?

Hi.
bleeding VW brakes can be a health hazard... lol

I renewed all the brake hoses , rear wheel cylinders and master cylinder , bleed nipples etc...

I used many bottles of brake fluid...

Jack the rear up so the bleed screw is higher than the master cylinder then undo both rear bleed screws
[new ones] and go have a cup of coffee..
by the time You get back all the air should have escaped thru the rear bleeders...
just make sure the master cylinder doesn't empty...

I find its best to renew the brake bleeders as they are very cheap but not indestructable...

You are supposed to bleed the brakes further away from the master cylinder first..
but I didn't...

Lee

http://community.webshots.com/user/vw68autobug 

havea look at the rear of the brakes drums on the rear and you may see the leak if its the wheel cylinders

or have a look at the reservior and which section is empty that will indicate either front or rear accordingally

it may also be the master cylinder pull the rubber boot away where the pushrod goes into it from the brake pedal

ideally you should bleed the rear brake first you need to buy some new bleed nipples as well