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Spring 2018 Project #1 underway....

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67gtonut

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Well, the weather finally broke today..... and I decided to at least get GTO set-up to make next change....

This will be another chapter in upgrading brakes....

Car was originally a 4 wheel manual drum car..... that was quickly changed years ago to what was basically a 1970 Front Disc setup.... still no power assist. Result was not acceptable, but I drove it for a few years like that. What was wrong is that I used a 7/8" bore master cylinder which came recommended by most forums/threads/project threads to be the proper size. Well...... although a 7/8" master will put out plenty of pressure, it lacked pushing enough fluid volume for the big piston front disc brake calipers, result was a mushy pedal that in the end did not deliver enough braking force.

After a few years of driving it that way.... and a few close calls. I made the decision and broke down and added a power booster for added stopping force. Now everywhere I read says that with Power Brakes.... go up to a 1 1/8" Master cylinder bore. Plenty of fluid flow and although gives less pressure, that will be made up by the booster. So that is what I installed ..... a 9" Booster and a Wilwood 1 1/8" Master. Result: Car stops VERY well now, but still wont lock brakes, so there is still more improvement to be had.Plus the pedal is very hard with very little movement.  The other issue is, the Wilwood Master is a beautiful piece but is really not designed to work with a Power Booster since on a GM car the booster makes the whole setup angle upward. With the design of the Wilwood master, you cannot fill up the reservoirs past halfway. After speaking to a Wilwood rep, he agrees, their masters are better suited for manual brakes where the installation is horizontal. But I drove it this way for a few years keeping an eye on the fluid level.

But now its time to give me a little piece of mind and replace the Wilwood master with a normal GM/Delco master that I can fill up properly. I am also going to go down from the 1 1/8"   to a 1" bore master. This should give more pressure then the 1 1/8" master but still give me enough flow to work with the GM Disc caliper setup. This should also soften the pedal up a little to allow for more modulation under spirited driving....

So this afternoon I setup car on my lift and got her ready for surgery tomorrow....

 

 

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