What's the difference in master cylinders?

[krue]

What's the difference between manual and power brake master cylinders. Both are drum/ drum. The manual one that is on the truck looks like a pre-67 m/c (has bolted on lid). The business end of both look identical as far as where the rod goes.

If there is any significant difference what's the best way to clean a master cylinder with rust in it?

[rage'nrat638]

piston size in side......if theres rust inside don't think i would trust it....seals may be shot????or will be as soon as you put on the brakes......make sure the e brake works......

[kaycee]

Auto STONE OR similer auto store and get a new 1 for under $ 20

[krue]

I went to get one at autozone and they only differentiate between drum/drum and disc/drum not between manual and power? Should I get one from a different year?

[Longhorn Man]

On these ones there is no power or manual style..they are the same.
At least that's what the part numbers come up with at all the major parts chains I have tried. I have bought 3 masters so far (one for each truck I have owned) and no trouble as of yet. (one was manual, and the other 2 power)

[krue]

Thanx man, that's what I figured, but you can never be too sure.

[70c10]

Does it matter whether it's the shorter car type or taller truck type?. My master cylinder is shallower than my dad's.

[Longhorn Man]

Hmmm, that is a good Q that I can't answer very well, but I will say that if it is on your truck, and you are not having any trouble...I'd run it.
The part you are questioning is nothing more than a resivour.
Is your dad's equipped with discs> They are a bit bigger than the drum ones.

[70c10]

Nope. He's got power drums like me. His is the taller truck resevoir that I believe was from a disc truck originally. I need a new one and thought maybe a taller one would work better.

[Southpa]

I've used three types of M/C and 2 boosters and never had problems with mounting and installation. Originally, the truck had a power drum/drum system. Then I swapped front ends with a 71 that had manual disc/drum system, and used that M/C. It worked fine but was the type with one hold down clip along the length (early model Delco) and leaked out the cap. Then I traded it in for a reman of the same kind, that leaked out the cap too. Then I traded that in for a double hold down clip (Bendix) and it works fine and doesn't leak. I also swapped my 1/2 ton brake booster for a 3/4 ton booster. Installed fine and works great.

Out of all that I haven't come across any differences in piston size or rod size or whatever, they are pretty much all interchangeable aside from the differences between power and manual brakes.