I have a few issues here. Car is 68 El Camino that was originally manual drums. I bought a full wheel kit from pirate jacks for the front.

First issue is master cylinder. I was told to buy a 74 camaro manual disk/drum master. It is way larger and doesnt have a recessed hole like my old master had.

1.) Is it ok to shorten the pushrod for the brakes? It does not have enough adjustability to make up for the non recessed part. Do I have the wrong master?

http://i52.photobucket.com/albums/g34/Brettd85/DSCN0178.jpg

http://i52.photobucket.com/albums/g34/Brettd85/DSCN0177.jpg

2.) The prop valve I bought from pirate is supposed to be for a disk drum setup. It came with a bracket that interferes with the wheel well if mounted to the master cylinder. So I will be mounting it to the chassis somewhere.

http://i52.photobucket.com/albums/g34/Brettd85/DSCN0179.jpg

The front has a port on top and bottom. These are for each front brake correct? The rear accepts a really large fitting and is supposed to be for the rears correct? How does this large fitting work? Will I be able to buy all the neccesary fittings to make the brake lines for this setup?

Thanks for your help guys. Brett

Well the two small lines on the prop valve goto the master cylinder. That cylinder looks huge but it may work im not sure. The big adapter to the rear lines is there to hold 10lbs of pressure to the drum cylinders and you should be able to get all the adapters at your local parts house or autozone or something. The other two smaller ports on the prop. valve goto the front disks. Heres a pictures:

http://www.piratejack.net/troubleshooting/valveFAQ_files/combocutaway3.jpg

hope that helps some im about to do a conversion on my 69

Tom

Why not just go with a master cylinder that matches the year of your car that would have been equipped with front discs. Thats what I would do. You dont appear to be going exotic with the brakes anyways.

I agree with Chris. You shouldn't have to grind down anything. Are you installing a power booster also?

You don't want to shorten the rod unless you use the Camaro rod and retention, could be dangerous. The Camaro rod is different, and has a different retention method to the pedal and master, you could modify the Camaro rod to fit the Chevelle pedal, but the 1" piston for nonpower disk isn't ideal anyway. Even if you spec the correct one for your application, like a 70 W-30 442 with factory nonpower disk, it will not be the correct replacement at any local auto parts store. They ALL have the wrong piston cup depth.

Best thing to do is use the stock OE combination valve, found at your local junkyard and the 15/16 piston master used on mid 70's Malibu with factory nonpower disks. Most people greatly prefer the pedal feel and It has the deeper cup. Kragens has the master for 30$ or less. Or you can order one from MP brakes, I believe it has the right cup depth but still with the 1" piston.

See this thread,

http://www.chevelles.com/forums/showthread.php?t=110307&highlight=malibu+master (http://www.chevelles.com/forums/showthread.php?t=110307&highlight=malibu+master)

Is it not true that a 74 camaro manual drum disk master will work though?

Should I just return it and get a 77 malibu master? Wont I also have to shorten the rod for that as well? Thanks, Brett

Yes it will, but you should use the correct rod to work with the short piston cup. It has a retainer cover that's pressed on and keeps the rod captive.

How could the rod go anywhere though? If it is adjusted properly, shouldnt the piston cup always be pushing on the pedal, keeping the rod from falling out?

Im thinking it might be a better idea to just trade it for a 77 master.

I wouldn't risk it, all pistons with the shallow rod hole that I have seen, have a retainer that holds the rod in place. When you're off the brake, the rod is floating. The only problem with the 77 Malibu master is that the reservoir is reversed, so you have to swap the lines. The good news is, it works with your rod and gives excellent performance. If want a direct bolt in, you might want to order the correct master from MP power brakes but definitely verify it has the deep rod hole.

Will do, Thanks all.

Except for the fact that its $140 from napa. Let me look at Kragens as someone suggested.

I recently replaced the master cylinder on my 70 Chevelle. It originally had the manual drum brake master cylinder. I replaced it with a front disc master cylinder for a 70 Chevelle. Everything bolted right up (even the brake lines.) The master cylinder was a reman. Cardone from Advance Auto Parts and only cost $14.00.

Might be easiest for you to just get the disc brake master for your application.