booster upgrade, MC compatability?
 

I am going to be putting pb on my 70 3/4t and wanted to check, does the MC need to be changed, or is there no difference between a manual and power brake MC? Is there a different booster for a 3/4t vs. 1/2t?
Anything else I should be concerned with.....I recently had to replace the MC on my daily olds. and it was relatively cheap, would I be better off to just swap my manual as a core for a new one?
Does a booster have to be rebuilt at all?
Any year interchange ability issues, or will all 67-72's work?
Thanks

Re: booster upgrade, MC compatability?
 

master cylinder is the same P/N power to non power as long as you are staying in the same series. 10 model and 20 model don't interchainge... but power to non power on a 20 is good.

The booster, you'll want a 20 series or a 30 series.

Re: booster upgrade, MC compatability?
 

Are you sure ? I thought they were diffirent boar size....

Re: booster upgrade, MC compatability?
 

Front disk brakes vs front and rear drum brakes do have a different bore size. The disk brake MC has a larger front and smaller rear reservior. The drum brakes have equal sized reserviors. I think SHELBY987 just wants to upgrade his drum brakes from non-power to power, so the MC will be the same. If he wanted to add disks as well, the MC's would be different.

Re: booster upgrade, MC compatability?
 

I believe on 1967-70, the 1/2 tons had a 1 inch bore master cylinder, and the 3/4 tons had a 1 1/8th. bore. They look the same from the outside.

Re: booster upgrade, MC compatability?
 

I am sorry, there is a difference betwqeen 67 - 70, and 71/72.
However, for one truck, the p/n is the same for the master, regardless if there is a booster there or not.

Re: booster upgrade, MC compatability?
 

ok, let me see if I have received all of this information correctly....I can keep my MC (power or manual, same thing) since I will be keeping my drums 4 corners. But to upgrade to power brakes, I need a booster from a 20/30 series truck, is this correct?
Thanks

Re: booster upgrade, MC compatability?
 

Yep. you got it. A booster off a 67 - 70 20/30 series truck.

Re: booster upgrade, MC compatability?
 

Oky, I am glad I got that cleared up. I thought I might have gotten the wrong master cyl for my 72 but I guess there is only one avaible so I have the right one. The manual brakes sure do give the leg a work out after driving a power brake car or truck.