master cylinder application question

[kaptnkaos]

Hey Guys ...

I went to pick up the master cylinder lid I ordered for the '68 CS...
It was differant than the one I need.
So I asked about a new master cylinder...
The one for manual brakes is $28, but the one for power brakes is $35.
So I made sure he knew I was working on a '68 F250 CS.
They only list one MC for all applications. MB, PB and PDB
I have a good PDB MS that came off the '71 what do ya'all think???
Should I try it or buy a new one???
It seems that the only differance is the length of the push rod.
The MC that's on it now both resevors are the same size, the one they showed me had a larger rear resevor...

KaptnKA S

[Wes]

there is a difference between Disc and drum fronts brake master cyls. Who's book ? Rock auto list 3 different part numbers for 1 manufacture depending on power/manual disc or drum.

Disc masters tend to have larger reservoir to supply larger disc pistons displacement. Didn't you convert to disc brakes ? I would get the MC using the donor truck as application.

[ToughOldFord]

I believe the large/small reservoir MCs are just the newer design, not relative to disc brakes. My '67 had the MC with both reservoirs the same size, but my '69 has the large/small reservoirs. Both trucks are power drum (all four wheels) brakes.

[James72]

I would try to use one with the larger res for the front brakes, the caliper dose need more displacement, but more important is that discs run hotter with a more direct effect on heating the fluid, so it will help with fluid cooling. And it is very important to set up the push rod correctly or you can have all kinds of nasty problems.



James