67 master cylinder lines

[bc65riv]

currently converting my 65 to dual master cylinder and need to know if the front reservoir serves the front or rear brakes or does it matter. also what about the rear reservoir?

thanx, frank

[JZRIV]

The front reservoir is for the front brakes. The one closest to the booster (rear) is for the back brakes.

Are you using the 67 proportionaing valve?

[Jim Cannon]

If your car has drum brakes in front and rear, you do not need a proportioning valve when you convert to a dual master cylinder on a first generation Riviera. The proportioning is already taken into account by the different wheel cylinder sizes front to back.

You can use your stock brake distribution block if you do the following:

- Remove the line from the block that runs to the rear axle

- Plug that opening in the block

- Fabricate a line to go from the front port on the Master Cylinder down to the distribution block. This will handle your front brakes.

- Fabricate a line to go from the rear port on the MC down to the vicinity of the line running to the rear. Connect new line to old rear ilne with a "union". That will take care of your rear brakes.

That's about it.

[Ron Luchene]

Jim,

I will tackle the dual master swap this weekend on my 65'. I have read the article on the ROA Tech site as well as several articles in the forum. I am aware that an O ring is required around the neck of the new master cylinder but am curious to know if this was required on the stock single reservoir. I do not see it in the shop manual nor was one installed on the master cylinder I just removed. Just curious.

Thanks - Ron

[Jim Cannon]

Ron-

To call it an o-ring is a bit of a misnomer. If you were to cut through the rubber ring with a knife, the cross-section would be a square, not a circle. It drops down into a groove that is cut in the cast iron neck of the master cylinder, where is inserts into the front of the booster.

I guarantee your old master cylinder had one. It is all smashed down into the groove and covered with dirt and weeping brake fluid, but it is there. Without this seal, you will have no power brake boost and that heavy car will not stop (trust me).

Look at the old MC carefully. Gently slip the old seal out with the tip of a small screwdriver. I recommend you not reuse the old one due to critical nature of this seal. If you can not find a new seal locally, you can buy one from "Booster Dewey" in Oregon -- (503) 238-8882 or Booster Dewey Power Brake Booster Exchange Inc. . If you call him right now, he will put the seal in the mail to you today.

I don't recall if this seal is mentioned in the shop manual. They leave out a lot of little things that are assumed to be common knowledge. (Common back in '63 is not neccesarily common now.)

[Ron Luchene]

Just checked again and there is definitely no seal present...not even stuck to the inside of the booster. This probably explains why I can't stop the car without standing on the brake pedal!

When I purchased the car locally the guy told me he had rebuilt the brake system. There is certainly evidence of this at the wheels and master cylinder. I suspected the issue with "hard brakes" was in the power booster since this was one piece he did not touch. What was odd to me is that when I performed the tests mentioned in the shop manual, the booster "appeared" to operate correctly. Since I was taking it apart this weekend I thought it would be a good time to upgrade to a dual master.

Anyways, I have the new master in hand and I still need to see if I can locate the seal in town. If not, I will give Booster Dewey a call. I also noticed that the new master has two different size fittings for the front and rear lines. Do I use a larger line for the front and convert it to 1/4" before the junction block or do they make larger fittings for the 1/4" line? Seems like a stupid question but I am not familiar with what hardware may be available.

Thanks - Ron

I am finally at a point where I can enjoy the car some before paint and body work in the fall

[Jim Cannon]

Oh... previous owner messed with it? Then all bets are off. You never know what you will find. Is there a groove in the old master cylinder, like on the new one, but with nothing in it? The seal can't stick inside the booster because it is down in the groove on the neck of the MC. I do not have a photo of the MC to show you.

You will need to make up new lines from master cylinder to distribution block and to the existing rear line. You can make them out of whatever size tubing you like and then put the exact correct size fitting on the line before doing the double-flares on the ends. Connect the new rear line to the existing rear line with a flare fitting block with a threaded T in it for the brake light switch. Puts the brake lights on the rear half of the system. The wires on the brake light switch are long enough to go down to the frame without cutting or anything.

[Guest mnkelsner]

Wow Thanks Jim !

[tim63riv]

Guys,

Ran into this o-ring situation when I put a dual system on my 63. I purchased an o-ring assortment from a local "big box" store and found a couple o-rings that would seal up the gap between my stock 63 booster and the 67 master cylinder that I installed. Without SOME type of seal, you'll have a vacuum leak and the power brake assist will be non existent.

Only 63 has the brake fluid pressure activated brake light switch, 64 and later went with a pedal activated switch.

HTH,

Tim

Edited October 5, 2010 by tim63riv (see edit history)

[Guest RivieraBear]

I don't have the O ring on my 63 with a power booster from a 67 and the original single reservoir and it stops just fine. What gives? Or am I missing something entirely? Besides the O ring, of course.

[Jim Cannon]

If your power brake booster is from a '67, then I do not think you need the o-ring. It is just needed on a car with the '63 booster (even if using a later model master cylinder).