brakes

[flip66]

I have noticed that there are 2 different types of brake master cylinders on the 69-72 trucks with power brakes. Some of them have the large reservoir in front and a small in the rear. There is another one where the reservoirs are the same size. It looks like the power drums have the lager reservoir in the front and the disc setup has the same size reservoir. I have converted front drum to front disc I have the 72 power booster and I have the master cylinder with the large front reservoir that the parts store showed to be a 72 but they also show the other to be a 72. I was wondering what Ya’lls experience with them is. And which one is seen most on trucks disc.

[Longhorn Man]

2 matching sized reservoirs are for drum brakes..67 - 70
One large reservoir and one small....disc/drum.

[400ex]

flip,

I just changed out my master cylinder on my '71 1/2 ton 2wd with factory disc up front. The master cylinder I got had the same size reservior for both front and rear brakes. More than one store showed the exact same thing.

I am not a brake expert but heres my uneducated thought..
To me it seems it shouldn't matter as long as you have enough fluid in them where it doesnt suck the reservior dry when you push the brakes to stop. I think that your front disc would use more fluid per pump of the brake since the area in the caliper is larger. The area in the rear cyliders seems much smaller. With that said, it seems the front brakes would have a larger reservior, but I dont know since mine has the same size reserviors.

This probably doesnt help but just my .02

James

[Longhorn Man]

To add to 400ex's thoughts...
the disc brakes are adjusted through use of brake fluid. Drums are adjusted mechanicly.