!980 Fleetwood Master Cylinder Upgrade Question

Soooo my '80 2 door Fleetwood needs a new master cylinder. You'd think GM could make stuff that lasts more than 33 years:crying2:

The existing looks like the typical cast iron type.

I remember the 77-79 Cadillacs used to have poor pedal feel with the caliper pistons retracting and taking some pedal displacement before the front brakes would do anything.

I also remember being able to swap the entire brake booster and master cylinder from an 81 through 85 RWD Cadillac to give excellent pedal feel. The newer aluminum/plastic master cylinders were designed to initially displace more fluid to the front brakes.

I would like to swap one of the newer master cylinders into my 1980. My booster is still OK. What I need to know is will it work with the existing booster and lines between the proportioning valve and master cylinder.

Performed this swap 3 times and I cannot remember what I used to do. Been out of auto repair for pay for 20 years.

Does anyone know? T.I.A.