suggestion for broken bleed screw

[Mark Switek]

I haven't broken a bleed screw in well over 20 years but I teach
automotive in a college in which occasionally a student breaks one and
here are some suggestions.
First of all, if the screw doesn't come loose with light to moderate
pressure I heat the screw with a torch. Get it red hot and quench it
with water. the heat will expand the screw and break the corrosion. You
may have to heat it a number of times to actually get it loose.
Since it is now broken, if you have access to a mig welder, you can weld
a nut onto the bleeder. This gives you something to grab onto and the
heat from the welding will help break through the corrosion. Again you
may go through a few nuts before you are successful.
After the bleed screw is out I will anti seize the screw into the
caliper. This along with making sure it has the rubber cap on it will
allow you to get it loose the next time you need to bleed the brakes.
The caps are hard to buy in the after market so if it is missing I will
put a gob of silicone gasket sealer over the bleed orifice to keep dirt
and water out so again it doesn't corrode back into the caliper. Hope
you have access to the tools and this process will help.

Mark Switek
92 s4
98 A4tq