hetzer : Lost Master Cylinder Info

[PseudoZone]

Lost Master Cylinder Info
Post by hetzer on May 7, 2006, 1:40pm

If memory serves, there used to be some info on swapping in a '76 Corvette manual brake master cylinder.

I picked one up this morning for $39, but could use the other info that went with it. Fittings, lines, whatever.

Anybody still have that info around?

(I tried the cached Google search to no avail.)

[Binford]

Re: Lost Master Cylinder Info
Post by binfordm715 on May 7, 2006, 2:03pm

I do. Here 'tis:

(posted 3/10/05) Many people want to get rid of the stock single line master cylinder. Either for better braking or to replace a worn out stock one. Many have done this already. This post is not about arguing what might fit or power or non power. This is a swap that I have done to my truck using the following parts. The part numbers are NAPA and the prices are what I paid for them last week.

1976 Corvette non power disc/disc master cylinder: #10-1371 $23.99
30" 3/16" brake line: #813-1205 $2.49
3/16" line plug: #131 x 3 $.29
3/16" line butt connector splice: #302 X 2 $1.99

I also got a reducer to go from the new master cylinder to the 1/4" stock line at the master cylinder, and a reducer to go from the new master cylinder to the new 3/16" line. I wasn't billed for them and do not see any part numbers on the parts. Use your new master cylinder and the line you have to buy to figure out the right ones.

The swap involved pulling the stock master cylinder off. Bolting the Corvette one on using the stock mount and pedal push rod. (I think adding 1/2 to 1 inch to the stock rod would make the pedal have instant pressure from its rest height. Instead of the 2-3 inch travel I get now. I will add power brakes later and see no need to mess with it twice.) I used the reducer and connected the stock brake line to the port closest to the firewall on the new master cylinder.

I then disconnected the line going to the rear brakes from the distribution block that includes the brake light pressure switch. I put the plug in the block. Put the splice on the line and connect the new 30" line to it. Slightly bend it so it goes toward the master cylinder. I now had a new line sticking about 10 inches above the master cylinder. I put a loop in it the diameter of my fist and it came out right at the master cylinder. I connected it and the reducer to the master cylinder. That is it.

I did pull the lines off of the master to "bench bleed" it on the truck using the pedal. I just hooked the lines back up and had firm brakes right away. I vacuum bled the right rear wheel cylinder to get the air the 30" line contained out of the system. I can now here the brake shoe springs working when I hit the brakes with the engine off. Not so before.

The 1976 Corvette had the option of a non power brake system with disc front and rear. That means the master cylinder had to push a lot of fluid to stop the car. They have the biggest pistons of the same size front and rear without any proportioning valve that can be found nationwide. That makes them a perfect swap into our drum front and rear trucks. Spicergear figured this out years ago and the rest of us are just using his research for our benifit. Thanks Tom.
_________________
Barrman
"Remember, if you didn't build it you can't call it yours."

[PseudoZone]

Re: Lost Master Cylinder Info
Post by hetzer on May 7, 2006, 8:00pm

Thank you sir!