[the APEMAN]

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.

 

[drmenard]

I'd be guessing but I think as long as you have rear drums like the 81 donner car you will be good.. I'm thinking if you got rear discs the 81 won't work right because I don't think it came with disc rear as a option... When I got my 78 disc -posi rear, I took the master cylinder and porporting valve.. But I never used them. I just put the drums on it and kept the 81 stuff...

 

[the APEMAN]

Thanks. No rear disc brakes for this guy. That miserable parking brake system ruins the whole deal.

 

[the APEMAN]

I caved and simply replaced the thing with the right part. Pedal feel is very good. Maybe they had fixed it by 1980. Haven't looked at the rear brakes in about 10 years and waiting to swap to one of my posi units when I can dig it out. Got a Mercedes W-140 in the way right now.