Brake Booster

In the front circuit, there is a booster/equalizer part.  It tries to boost the pressure to the front brakes compared to the rear by a piston arrangement that causes more fluid to go to each front caliper than to the rear ones.  It is also acts as a T to split the line to each front caliper.  Finding someone to rebuild these is difficult as well as sourcing the three seals that are inside.

Just getting it apart was difficult.  One end came apart (with the help of an impact wrench).  It took my neighbor reefing on the my 600 ft-lb 3/4" torque wrench while I kept the work bench from moving. Here's the disassembled parts (in order) for a disk brake booster:

I have a lot of corrosion on the aluminum piston towards the right in the picture above.

I was able to have a machinist make a replacement part at a fairly reasonable price.

I've been keeping all of the parts on a wire so they can't get out of order.  However, when I was trying to get it apart, some parts fell out so I'll have to figure out the correct order for a couple of them.

To help in this, I have a picture of a similar booster used in the drum brake PF coupes, courtesy of John Vardanian.

The parts aren't quite the same, but the design works the same, so I'm sure that I can sort this out.