rayL79

I'm really enjoying my 66 L79 roadster that I bought 2 years ago and have driven way too little. This is a nice, positive story that I hope helps others. I knew from the beginning I wanted a dual master after almost losing the brakes due to an unseen leak into the passenger compartment. I agonized over how to do it for too long, looking at all the kits that are available on line, and getting some help from this Forum. I finally got it done today and it was way too easy (and inexpensive), and is easily reversible if someone want to go back to stock.
I simply bought a 1967 Corvette master cylinder (AC Delco) from RockAuto for something like 50 bucks. Then I got 2 flare adapters (one 9/16 to 7/16 and one 1/2 to 7/16 to convert the master cylinder outlets to accept standard 1/4" tubing fittings which are on the brake lines in the car. I also needed a 7/16 flare plug to put into the brass block where the rear brakes used to come from.
I had my local trusted mechanic (not a Vette guy) do the work and he charged me for an hour and a half.
All he had to do was:
Bench bleed and install the new master cylinder
Re-bend the front brake line which now had to enter from the side instead of the front.
Remove the rear brake line from the brass block in front and re-bend the line to hook up to the rear outlet of the new cylinder.
Put a plug in the block where the rear brakes used to be fed.
Bleed the system.
The brakes feel great and lock up if you stomp on the pedal just like before.
The whole thing cost me a little over $200 (labor included) and I would recommend it to anyone driving a 65 or 66 with manual brakes.
Ray

Avispa

Thanks for that, ray. The feds made the OEMs put those things in for '67 for a reason. That and collapsible steering columns, fully padded dashboards and plastic or rubber shields around the window cranks, radio *****, heater controls and mirror. Pre-67 cars were kinda death traps.

Tom Austin

Hi Ray,

Happen to have any photos of the finished project? Thanks!

Tom

Mike mgchevy

I'll take that death trap off your hands, at a discount of course. Probably will have to crush it due to it being so dangerous.

RatDog

Very cost-effective investment in safety. Good job.

Steve

rayL79

USMC 0802

Great post.

Where did did you get the flare adaptors?

Thanks

rayL79

Matt,
I got the flare adaptors locally at AutoZone and AdvanceAutoParts. They're pretty common...most parts stores have an assortment.
Ray

Railroadman

Nice!

There has been discussion on here, pro and con, about power brakes. Obviously you decided not to go with the booster etc. Any insight into your decision? I'm still on the fence with mine.

Larry Wegner

I did't know it could be that easy! Great info, do you know if I can covert my 64 manual cylinder car using the 67 manual master cylinder the same as you did? I would like the safety update. Thanks.

rayL79

I love the manual brakes...the car stops on a dime and the brakes feel great. I also had a 65 back in my younger days and I thought the same thing. I would never even think about adding a booster.
Ray

rayL79

I don't think it's the same with the 63 and 64 drum brake cars. I believe they have a 7/8 bore master cylinder and the 67 cylinder is 1 inch. This will result in slightly higher pedal effort on your car. There may be other issues too...you should talk to someone who's done it.
Ray

rayL79

Just to clarify something...I may have misspoken in my original post. 65's may have a 3/16 line going to the rear brakes instead of 1/4". If this is the case, you would need a different adapter for the rear port of the master cylinder- 9/16 to 3/8 I believe and a different plug for the brass junction block. I'm also assuming that a 65 has basically the same line routing as a 66. If I'm wrong I apologize.
Ray

Mike mgchevy

Actually all 4 wheel drum cars used 7/8" master 63-65

lonzoo

Does anyone know if this style conversion would work on a 63? I would love to do this on mine . Also what year master cylinder to use??

Tigershark3

I did the exact same this when I first bought my '66. Same setup and without the balance block. Not sure if you painted yours before you did the install, I did not, so I keep a light coating of WD-40 on it to keep it from rusting. It still looks like new. If I ever have to remove it I'll paint it then. $.02 deposited.

lawdawg

Ray,
im glad you did the conversion, it's one of the first things I do to a 65 Or 66 non power brake car. It's nice isn't it, not sure why a lot of people argue with the added safety of this conversion.

however -


Someone should step in here on this conversion for 63 and 64 - is the 67 master cylinder compatible w drum brakes? I don't know, but I would hate for someone to find out the hard way.

JohnZ

Drum brakes require an RPV (Residual Pressure Valve) to maintain a low level of hydraulic fluid pressure in the system, and the GM drum brake master cylinders have such a valve inboard of the single outlet. The '67 dual master cylinder (1" diameter bore) is designed for 4-wheel disc brakes, and has no RPV's - you'd need to add an aftermarket external RPV at each master cylinder outlet to provide proper brake system operation.

Mike C#2

Ona 63-64 or uncommon 65 drum brake car you should be able to run a passenger car 4 wheel drum brake master cylinder from a 67 or newer car such as a Camaro. It’s common to run the Corvette master on the other cars so no reason that couldn’t be switched around.