My new 1968 Nova L79 project.

[jasonL78]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonL78</div><div class="ubbcode-body">Ok I need a little help. My original master cylinder that was in the car could not be rebuilt. Well that is what the shop told me that I sent it to. They gave me a replacement but it was the 69 master cylinder, so I sold that one. I found the correct 68 master cylinder and had that one rebuilt. Well when I went to install the master cylinder on my original booster it wouldn’t go on all the way? Almost like it was bottoming out inside the master cylinder. I remember when I bought an aftermarket booster it came with a long and short rod. So I checked another 68 power brake booster I have and it also had the long booster rod. So I got out the ruler and measured when the piston is pushed in and I measure 1 5/8” stroke on the master cylinder piston. Then I measure the rod sticking out of the booster and sure enough it is bottoming out the piston.
So this is my question, with the smaller rod put into the booster only about ¼ “sticks out. Is it safe to say I need the short rod? When they rebuild the master cylinder can they change what size rod the master cylinder uses? Not sure why I would need to change my rod?
Here is a picture of the 2 rods the gold one is my original restored and the silver one is the shorter one. My original measures 4” and the shorter one measure 2.5”.



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I figured my problem out with the master cylinder. When I had my master cylinder rebuilt they must have changed the piston to except the short rod that goes into the power brake booster. I had an old reproduction master cylinder that uses the long rod. You can see the differnece in the pistons in the picture.