How come all my manual drum cars have disc master cylinders?
1. Are the manual disc MC's an acceptable interchange for a drum car, the residual valves notwithstanding?
2. What are the spec differences between the early and "late" manual drum MC's? The books call for different part numbers.
It amazes me that 3 different cars had the wrong master installed. Is there REALLY a manual drum pre-'71 or so master or do they truly interchange with the power drum cars? Sorry for the long post but there is a lot of confusion on this. Thanks!
A lot of things vary from year to year, somodel to model depending on brake pedal leverage and the wheel cylinders.
The aftermarket guides are sometimes just wrong in their attempt to reduce the different part numbers they stock.
1968 is a particularly tricky year on the mechanicals (changed to tabbed shoes, but before the change with the self-adjusters)
I beleive this is also correct for '67-'68 MCs
Drum Brake Service Highlights (Session 260) from the Master Technician's Service Conference
In 1970, non A-body disk cars got floating calipers. And the 9" A-body drums go away.
1970 Chrysler Imperial Hydraulic Brake Service Guide from the Master Technicians Service Conference Session 274
Those disk/drum master cylinders are now harder to find. So definately keep if you need, or keep an ear open for people looking.
"Mastershake" on Moparts has written up at least one article on correct master cylinder castings and part numbers. He's made some updates and corrections since it originally came out but still a good starting point especiall for the things you asked about.,
Moparts - Members In Print, Brad Schroeder "Pumping Points", Mopar Action (jpgs)
http://www.moparts.org/Tech/MoparAction/Master_Cylinder.pdf
I started a cheat sheet
here for A-body disk master cylinders.
It would be great if people add info to it.
Years___Application_____________p/n_______Bore
1966... Fixed Ft calipers, Manual.....................1"
1966... Fixed Ft calipers, Power......................1"
67-70.. Fixed Ft calipers.............2808600.....1"
71-72.. Fixed Ft calipers.............3461178.....1 1/32
73-74.. Floating caliper, Manual...3580146.....1 1/32
73-74.. Floating caliper, Power.. .3580112........15/16
1976?......................................____4647..........15/16
