Into the world of hydroboosters I go. What a day. I took off the hb and made an extra spacer after I disconnected the brake pedal arm and pulled out another 1/2". So I moved the unit that distance from the firewall. I also went to junkyard and took apart about 4 units and took the rods that connect hb with master, and a larger spring for the return of the b.pedal. Since I took so many rods I played with lengths.
I also bought two 75 chebby k20 4x front calipers for $17 ea. at AZ. I thought the Caddy calipers were big! These things look huge. I'm giving up on the Caddy ebrake calipers. I wanted to solve the problem of my r.rear dragging. I can't wait to try them out. When I have the $ I'll invest in a set of the TSM custom ebrake calipers for this truck. But until then, these chebby cals will lock up a set of 38" tires!!
I thought that while I was back there I'd replace my leaking l axle seal. Heck, since I have a spare set, I'm going to replace them both.
I'm hoping there won't be any more episodes of the self engaging brakes. This morning they were locking so bad I could not drive, and had to change the hb master rod length just to get it home. And since it didn't act up all that way, I knew I had something. It was rod length, and, hopefully, not p/s fluid contamination damage.
To the poster who mentioned that residual valves are only used when the master is lower than the calipers: That is not true. A 2lb residual is commonly used in disc brake systems. With these modern systems, however, it is usually IN the master. ABS brakes, in Orange, CA, installs them in all their systems.