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67-72 Master cylinder differences

by Livrat

 

Okay guys.. Here's what I know...

The first picture is of a 3/4 ton Disc Brake booster and MC.. it is a Delco Moraine booster..

The second picture is of a 1/2 ton Drum brake booster and MC.. you can usually identify this one by the Brass distribution block and the master cylinder is smaller than a disc brake one... this booster is a Bendix..

The third picture is of a 1/2 ton Disc brake booster and MC.. you can tell by the "cast iron" porportioning valve and the MC has larger resevoirs than the drum one

Both Drum brake and disc brake 1/2 tons use the same Booster..

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I have found two different styles of disc brake MC's.. both will interchange with each other as long as 1/2 ton stay with 1/2 ton and so on..
The first two pictures are of 1/2 ton MC's
The third picture is of the two different 3/4 ton ones..

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The first picture is of the back of a 3/4 ton disc brake MC.. You can see how shallow the hole in the piston is for the rod..

The second picture is of a 1/2 ton drum brake MC.. you can see how the rod goes into the piston much further than the 3/4 ton one..

The third picture is of the 1/2 ton Bendix booster (On the left) and 3/4 ton Delco Moraine on the right..

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Now on to the mounting brackets.. Yes they are different between 1/2 and 3/4 ton!!..

The first picture is of the 3/4 ton Delco Moraine booster... the mounting studs are approx 3- 3/4 inches apart...

The second picture is of the 1/2 ton Bendix booster.. the mounting stud are approx 3 1/2 inches apart...
The third pic is of the 1/2 ton Bendix booster with the correct brackets..

The fourth pic is of the 1/2 ton Bendix booster with the 3/4 ton Delco Moraine brackets..

You can see they don't quite fit.. but I suppose if one is "creative" and with a "round" file you may be able to line things up.

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Next I found the there is a slight difference in the lenght of the rod from the booster to the bracketry...
the 1/2 ton Bendix booster has a rod approx 4 3/4 inches long and the 3/4 ton Delco Moraine has a rod just over 5 inches long...

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