master cylinder upgrade

-
entropy

entropy

Well-Known Member
Joined
Mar 20, 2007
Messages
98
Reaction score
2
Location
Florida
I'm looking to upgrade the bone stock, manual drum master cylinder in my '71 swinger. Does anyone have any recommendations for a quality piece that won't break the bank.

I've seen some conversions that used a late model Mopar unit and adapter plate, but not sure if this is the best option.
 
you don't have alot of options since you have drum brakes. First thing I'd do is find the good old 73 up disc setup and do the swap. Then I'd put on the newer aluminum master.
 
i paid like $70 for my conversion including the m/c and plate off a guy in the classifieds on moparts. Its a big piston m/c so it takes a little bit of leg to get things goin. Just like getting a heavier clutch imo, little heavy to begin with and you just get used to it :D


000_0028.jpg
 
Why do you feel you need to upgrade?

You won't get any improvement in brake performance. If the one you have is failing just go to the local parts store and get a rebuilt one, they are around $20.

I agree with dusterdon, do a disk brake upgrade. I went from 9" drums to the 73+ disks on the front an 10 x 2.5 drums on the rear and the braking performance improvement is like night and day.
 
I just didn't want the work & expense of the disc swap. It's not like I drive the car a lot. I did talk to a guy who put the late model large piston MS on his Demon, & he said his braking improved over stock.

I dunno...just thought it was a simple upgrade I could do for about a hundred bucks.
 
FWIW, changing the bore size of the MC increases/decreases the leg effort for a given amount of stopping force, it doesn't change the overall stopping ability of the brakes.

As always you give something to get something. If you decrease the bore size of the MC you will increase the pressure in the system for a given amount of force applied by the leg at the expense of having to move the pedal further to have the shoes contact the drums. Conversely if you increase the bore size the pedal travel is reduced but it takes more leg power to get a give amount of pressure in the system.
 
dgc333 said:
FWIW, changing the bore size of the MC increases/decreases the leg effort for a given amount of stopping force, it doesn't change the overall stopping ability of the brakes.

As always you give something to get something. If you decrease the bore size of the MC you will increase the pressure in the system for a given amount of force applied by the leg at the expense of having to move the pedal further to have the shoes contact the drums. Conversely if you increase the bore size the pedal travel is reduced but it takes more leg power to get a give amount of pressure in the system.
Click to expand...


Mine is increased (bore size)..more pedal effort. I felt the need because i did a power brake to manual brake swap and thats what i wanted, i paid like $60 for the setup. Its nothing overwhelming, just firmer lol.

-Mike
 
So let's say I did swap to the new MC, would that work if I did go to the disc setup in the future?
 
No, master cylinders for drum brakes have residual valves to keep a small amount of pressure in the system so air does not get drawn in past the seals. A disk mc doesn't have the residual valve on the disk side because there is no spring at the caliper to force the pads away from the disk when your foot is removed. Also, a disk/drum mc will not have equal size reservoirs. The disk side is larger because as the pad wears the piston moves out of the caliper requiring more fluid. They are sized so the fluid in the reservoir does not run out before the pads are worn out.

IMHO, I wouldn't replace a functioning mc until you decide to do a upgrade to disk brakes then get the proper mc for the disk system.
 
Well, I put the late model alum. master cylinder on my drum brakes and it works fine !...I did it for weight purpose for racing...The only difference was it was 2 bolt instead of 4...I covered the hole w/ alum., drilled 2 new in place and installed...It works great !...Lee
 
You must log in or register to reply here.
-

Back
Top