1963- Riviera dual master brake cylinder conversion for drum brakes

[OldGerman]

Hello

Has anybody swapped the OE single reservoir Master Brake cylinder with a Dual ?

I‘m looking for a bold on Dual MC for my 1963 Riviera.

I want‘t to keep the Stock booster, add some front brake lines and a adjustable proportioning valve for the rear brakes. 

I would Be greatfull If somebody could tell me a part number and source .

 

Thank you all,

Frank

Edited March 3, 2019 by OldGerman (see edit history)

[RivNut]

There is a complete write up on the Riviera Owner's website.  Part numbers, instructions, and scaled drawing for a bracket you might need. It's in the Tech Tips section in the Member's Only part of the website.

[Riviera63]

1 hour ago, OldGerman said:

Hello

Has anybody swapped the OE single reservoir Master Brake cylinder with a Dual ?

I‘m looking for a bold on Part. Wan‘t to keep the Stock booster, add some front brake lines and a adjustable proportioning valve for the rear brakes. 

I would Be greatfull If somebody could tell me a part number and source .

 

Thank you all,

Frank

 

 

I did this conversion several years ago following Jim Cannon's (he is the 1963 Tech adviser for the ROA) conversion. Use the master cylinder for the 1967 Riviera, it is a bolt on. You can find either of the versions at your local auto parts stores. I got mine from NAPA. I kept the original booster as you are doing. His conversion is pretty straightforward and simple. I have not had any problems whatsoever. 

 

Like anything, there are multiple ways to do it.

Here is what I recommend:

Keep the factory distribution block on the frame. Remove the line going to the rear axle and plug it. Connect the port on the block that goes to the stock MC up to the FRONT port of the dual MC. You need to fabricate a line to do this, with double-flared ends at both ends. Put some slack in the line by making a Z-shaped portion or a coil The tube nut size on the front MC port is different from stock MC, but is easily obtained. That takes care of the front wheels.

For the rear axle, you want to fabricate a new line that goes from the REAR port of the dual MC down to the frame in the vicinity of the distribution block. Include a coil or a Z for slack. Use a T-fitting style union made for brake light switch to connect the end of your new rear line to the existing rear line that come off of the original distribution block. The 2 union-type ends will be tube fittings. You connect the line to the rear axle to one of them and the line up to the dual MC to the other. It is equivalent to a straight-through union. The T-part of the fitting is 1/8" NPT, not flared tubing. The stock brake light switch screws right into it. The wires on the stock wiring harness are long enough to reach down to the frame by the distribution block. You do not need to splice any electric or cut anything.

To keep the lines from vibrating against each other, I tied the lines to each other with a couple of small zip ties.

I got the 3/16" tubing, the master fittings STN-7 and STN-5, the T-fitting BS-01(the T-fitting comes with a new brake light switch attached) and everything from Inline Tube. I might have gotten the plug from them, I don't remember. Call them.

You do not need a proportioning valve for the drum-drum system. Crude proportioning is already included in the wheel cylinder cup/piston diameter difference between front and rear. Connecting lines as I describe will maintain the factory proportioning, for better or for worse. (I used to design brake systems.)

The brake light switch is hard to bleed air out of. Fill it with fluid before screwing into the T-fitting. Try to keep it contacts down until you bleed the system, then invert it.

Regarding which dual MC to use:

You need to remove your stock MC from the car and look at the end of the piston that the booster pin presses against. It will be either a (roughly) 1" deep hole or a 1/4" deep dimple. The new dual MC that you install needs to have that same depth "hole". It will be either one or the other. Trying to put the wrong one in will not work.

If you are keeping your STOCK booster, you need to put an o-ring on the neck of the new MC where it inserts into the booster, or else you will have no boost (due to vacuum leak at the neck). Either move the original o-ring over to the booster or get a new o-ring. The only guy I know that sells this special o-ring is Booster Dewey out in Oregon. You might try NAPA or other places and find it. If you were to "cut" the o-ring and look at the cut surface, it would not be a circle. It would be a small square. So it is not really a conventional o-ring. It is specific to this application.

 

The write up on the ROA website is essentially the same as what Jim outlined but, somewhat more complicated. With the above method you don't have to replace the distribution block and fabricate a mounting bracket, your original distribution block is utilized. Also, if you are doing this on a 63 you do not have to mount and rewire a new brake light switch as outlined on the website. An original style brake light switch is included with the T from Inline Tube. The wires that ran to the switch on the original master cylinder are long enough to reach the new switch in the T. 

 

Hope this helps.

 

Bill

[psychostang]

 

I apologize, I must of read it too fast.  I thought he was converting to dual channel, with front disk.  Yes, my MC will not work. 

Edited March 3, 2019 by psychostang (see edit history)

[RivNut]

1 hour ago, psychostang said:

I have one for sale?  

 

Really good price for this m/c but it won't work on a drum/drum set up.  Not trying to bust a sale but also don't want the buyer to use it in the wrong application.

[Riviera63]

4 hours ago, OldGerman said:

Hello

Has anybody swapped the OE single reservoir Master Brake cylinder with a Dual ?

I‘m looking for a bold on Part. Wan‘t to keep the Stock booster, add some front brake lines and a adjustable proportioning valve for the rear brakes. 

I would Be greatfull If somebody could tell me a part number and source .

 

Thank you all,

Frank

 

If I remember correctly, I'm pretty sure this has been discussed before on the forum regarding the proportioning valve, that it is not necessary.

 

Bill

[RivNut]

3 hours ago, Riviera63 said:

You do not need a proportioning valve for the drum-drum system. Crude proportioning is already included in the wheel cylinder cup/piston diameter difference between front and rear. Connecting lines as I describe will maintain the factory proportioning, for better or for worse. (I used to design brake systems.)

The brake light switch is hard to bleed air out of. Fill it with fluid before screwing into the T-fitting. Try to keep it contacts down until you bleed the system, then invert it.

 

Old German,

There are subtle differences in the three years of the 63, 64, and 65 Rivieras.  63's have a fluid activated brake light switch, 64 has a manual switch activated by the brake pedal arm.  If you're working on a '63, you have to do something with the o-ring as Riviera63 stated in his post.  On a 64 that is not necessary according to Booster Dewey, I didn't do it on my '64. It would help of you were to tell us exactly which year you have rather than grouping the 63-65's into one category when they are actually three separate categories.  I did not fabricate a new rear line.  I used a union to connect the rear port and brake line from the master cylinder directly to the existing rear brake line.  While you're at it, now is a good time to refurbish the wheel cylinders, install new brake hardware, and of course turn your drums and install new shoes.  Make sure that when you turn your drums, you don't exceed what the chassis manual states as mininum thickness for the drum linings.  If you're out of limits, J&G can reline your aluminum drums with new steel liners.

Edited March 3, 2019 by RivNut (see edit history)

[OldGerman]

Good morning, 

thank you so much for very good and deteiled information.

Ed, you are right, I should have pointed out I have a 63 Riviera. 

I have edited the subject in the Titel.

I will dig into the Riviera owners Website Outlining.

 

Bill, Thank you so much for that detailed Description. I have all the tools required to manufacture brake lines with double flairing fittings.

 

I was thinking about an extra rear adjustable restriction due to overbreaking in the rear on my current original setup with all new brake lining in the front and rear.

 

 

Thank you so much.

Frank

Edited March 3, 2019 by OldGerman (see edit history)

[Jim Cannon]

12 hours ago, OldGerman said:

Good morning, 

thank you so much for very good and deteiled information.

Ed, you are right, I should have pointed out I have a 63 Riviera. 

I have edited the subject in the Titel.

I will dig into the Riviera owners Website Outlining.

 

Bill, Thank you so much for that detailed Description. I have all the tools required to manufacture brake lines with double flairing fittings.

 

I was thinking about an extra rear adjustable restriction due to overbreaking in the rear on my current original setup with all new brake lining in the front and rear.

 

 

Thank you so much.

Frank

 

Frank-

You do not really need to add a proportioning valve to the rear brakes.

 

Are you experiencing overbraking on the rear wheels now?  Or just anticipating the potential problem?

 

I wrote the detailed instructions that were posted above.  Let me know if you have any questions.

 

 

[OldGerman]

On 3/3/2019 at 8:58 PM, Jim Cannon said:

 

Frank-

You do not really need to add a proportioning valve to the rear brakes.

 

Are you experiencing overbraking on the rear wheels now?  Or just anticipating the potential problem?

 

I wrote the detailed instructions that were posted above.  Let me know if you have any questions.

 

 

 

Yes I have overbraking on the rear wheels (or not enough in the front)

breaking Power was good in the front on brake Test stand, but this is not a very dynamic Test.

frank

[Jim Cannon]

3 hours ago, OldGerman said:

 

Yes I have overbraking on the rear wheels (or not enough in the front)

breaking Power was good in the front on brake Test stand, but this is not a very dynamic Test.

frank

 

OK, well then I guess you should add a proportioning valve to the setup and dial the pressure back on the rear axel a bit.  You need to test on the road, on dry surface, with hard braking.  That shifts the weight forward off of the rear tires, so you need less pressure back there.

 

 

[Erick R]

Hi All, OK I was on the Rivi org web site and read about the dual master conversion and now this post. So now I am a little more confused. Do I need a proportional valve or not?? If so what would the part number or is it the same proportional valve for a 1967 Riv with all drum brakes?

 

I have a 1964 riv (for a few weeks now) with a 425 and air. since everything is still in the car working room is really tight.  In looking at some of the disc brake conversion the proportional valve is mounted right to the master cylinder which may make things easier but I do not see any for a drum/drum setup. Could I mount the proportional valve that way for the drum/drum dual master cylinder conversion??

 

It is a big can of worms to open up I want the dual master for safety but I did not want to get half way in and say to myself "what did you get yourself into"  The master cylinder part is easy the brake lines IF they come out of the old master cylinder and proportional valve is the hard part. Not much room to measure and work in .  Just trying to get a good idea of the problems (crying sessions) I have to look forward too. If anyone who has done this conversion and has some good close up pictures of how things look, that would be a great help.

 

Thanks again for all the support in answering my questions.

Erick

 

 

 

[BulldogDriver]

https://www.jamcosuspension.com/product/1963-69-buick-riviera-power-brake-conversion-pbb6369
 

or something like that. Will need to rework the brake lines going to the proportion valve.

 

Ray

[telriv]

1st. off I wouldn't use Jamco for ANYTHING.

No valve needed for drum brakes.

Nothing special for brake lines. The front brakes run a new line to the distribution block where the original line went & put a plug that connected to the rear line.

For the rear just make a line to connect with the rear line already there.

Don't forget to curl at least the front line.

 

Tom T.

Edited May 7, 2022 by telriv (see edit history)

[Jim Cannon]

4 hours ago, Erick R said:

Hi All, OK I was on the Rivi org web site and read about the dual master conversion and now this post. So now I am a little more confused. Do I need a proportional valve or not?? If so what would the part number or is it the same proportional valve for a 1967 Riv with all drum brakes?

 

I have a 1964 riv (for a few weeks now) with a 425 and air. since everything is still in the car working room is really tight.  In looking at some of the disc brake conversion the proportional valve is mounted right to the master cylinder which may make things easier but I do not see any for a drum/drum setup. Could I mount the proportional valve that way for the drum/drum dual master cylinder conversion??

 

It is a big can of worms to open up I want the dual master for safety but I did not want to get half way in and say to myself "what did you get yourself into"  The master cylinder part is easy the brake lines IF they come out of the old master cylinder and proportional valve is the hard part. Not much room to measure and work in .  Just trying to get a good idea of the problems (crying sessions) I have to look forward too. If anyone who has done this conversion and has some good close up pictures of how things look, that would be a great help.

 

Thanks again for all the support in answering my questions.

Erick

 

 

 

Erick-

If all you are adding is a dual master cylinder, to replace the original single MC, you do not need a proportioning valve.

 

BUT, if you are also putting disk brakes on the front with the dual MC, then you DO need a proportioning valve.

 

Hope that helps.

[OldGerman]

Proportioning valve is not needed for Drum/Drum brakes, but I‘ve added an adjustable valve to reduce power to the rear just in case it will tend to overbreak in the rear. That was the case with the single master cylinder. 

[Erick R]

Hi Frank thanks for the picture. OK what is the part number for the adjustable valve . do you custom make the bracket? if so you you have a few dimensions you could share. Thanks.

Erick 

[OldGerman]

Erick, 

the adjustable prop valve was purchased at summit  i. E. SUM G-3905.

The Bracket is self made from a piece of flat steel, it took me a few try and errors until it fits and allignes with the bendings of the brake lines. unfortunately, the bracket does not match the Sketch I made in the beginning made from the measurments I had taken.

There is not a lot of space between master and cylinder head, so I tried to keep the valve as close to the master as possible. That was also a challenge for the Tube bendings. Some of them took me several try‘s and a lot of wrong bended lines ended in the trash. 

 

Edited May 14, 2022 by OldGerman (see edit history)

[Erick R]

Hi All need some help I have a 1964 riv  with a bendix booster, I used the 1967 riv master cylinder for bendix for front drum. I cannot get any pressure to the front drums, thought it was a bad master cylinder ,swapped it out same problem. Brakes bleed fine and if you go to the floor with the petal you get a little pressure but not enough to stop the car. The car stopped fine before the swap. You can see the shoes expand (with the drum off) but you cannot get any pressure rears have a little depending how you set the adjustable proportional valve. 

 

Thanks for any help.

[steelman]

You have a bad booster. Most likely the check valve has failed. Needs to be rebuilt to be sure. Look up “Booster Dewey” and talk to him.

[Jim Cannon]

59 minutes ago, Erick R said:

Hi All need some help I have a 1964 riv  with a bendix booster, I used the 1967 riv master cylinder for bendix for front drum. I cannot get any pressure to the front drums, thought it was a bad master cylinder ,swapped it out same problem. Brakes bleed fine and if you go to the floor with the petal you get a little pressure but not enough to stop the car. The car stopped fine before the swap. You can see the shoes expand (with the drum off) but you cannot get any pressure rears have a little depending how you set the adjustable proportional valve. 

 

Thanks for any help.

 

Did you confirm that the hole depth in the piston on the new MC matches the hole depth of the old, original MC piston?

 

Did you replace the flexible brake hoses to the front wheels, and flush the lines?

 

 

[EmTee]

17 minutes ago, Jim Cannon said:

Did you replace the flexible brake hoses to the front wheels, and flush the lines?

 

This ^^^

[1965rivgs]

4 hours ago, Erick R said:

Hi All need some help I have a 1964 riv  with a bendix booster, I used the 1967 riv master cylinder for bendix for front drum. I cannot get any pressure to the front drums, thought it was a bad master cylinder ,swapped it out same problem. Brakes bleed fine and if you go to the floor with the petal you get a little pressure but not enough to stop the car. The car stopped fine before the swap. You can see the shoes expand (with the drum off) but you cannot get any pressure rears have a little depending how you set the adjustable proportional valve. 

 

Thanks for any help.

  More info is needed for a thorough answer. Did you convert the front brakes to disc? If so, why use a master cylinder for "front drum"?. If not, why do you have a proportioning valve? More info needed...

 

Tom Mooney

[XframeFX]

3 hours ago, Jim Cannon said:

Did you confirm that the hole depth in the piston on the new MC matches the hole depth of the old, original MC piston?

 

4 hours ago, Erick R said:

depending how you set the adjustable proportional valve.

Do not use a proportioning valve. It is not needed with 1.25" wheel cylinders up front and 1.0" in the rear.

 

I'm into this right now but sticking with the original single circuit and the original Master Cylinder because I have $$$ in a rebuild last month with a SS Sleeve. Further complications in realizing I used DOT5 silicone fluid back in 1990, the reason my switch failed. Have to re-do my hydraulics. Frustration with sourcing hoses and front wheel cylinders (1.125"). Can only source rear parts, cheap but this is costing with my bad logistics.

 

For Bendix, the plunger depth should be 1.625" deep.

 

The booster check valve has effect with the engine off. Where to source a 1963 inline check valve?

 

I sent my Power Booster across Canada for rebuild. The quote was $$$ only to receive it painted black! Upon follow-up, yes I could've had it plated for an extra $250 but never offered it up front. Turns-out, there are 2 places within 15 minutes of me that could've done the Power Booster! Lesson, check locally before sending off your Power Booster and ask about plating!

I heard Booster Dewey is now in Washington State?

 

Tip: A 1964 Cadillac dual master cylinder has both ports with 1/2" flare nut fittings with a 1 5/8" depth for Bendix boosters.

[RivNut]

Buick also used Morraine and Bendix brakes in 1967. Are you sure that you got the correct master cylinder to match up to your booster?

[XframeFX]

10 hours ago, XframeFX said:

Do not use a proportioning valve. It is not needed with 1.25" wheel cylinders up front and 1.0" in the rear.

Type-O. Should be 1.125" wheel cylinders up front.

[Erick R]

Yes it is the correct master cylinder a delco will not go on a bendix booster . the stroke of the rod coming out of the booster is 1.5". even pumping the brakes does not help.

Trying a different master cylinder again different brand. no real pressure on any of the wheels. Thanks for getting bak to me I will let you know what happens after third try master cylinder.

 

Erick

[dr914]

Here you go was thinking about purchasing myself:  https://www.ebay.com/itm/162399854449

[XframeFX]

On 6/30/2022 at 5:41 AM, Erick R said:

depending how you set the adjustable proportional valve. 

oooh, you are using Frank's setup with the manual valve from Summit?

[Erick R]

yes with the manual valve OK a question the knob states increase /decrease so I am assuming turning it the increase direction sends more fluid to the rear brakes correct? And if it is all the way down I am assuming that it is basically a pass through. 

 

Thanks again for all the help

Erick

[XframeFX]

4 hours ago, Erick R said:

I am assuming turning it the increase direction sends more fluid to the rear brakes correct?

I'd start with it wide open, whatever direction that is. PM Frank on it's operation. Scroll up for "Old German". It is not a proportioning valve.

[Erick R]

Hi All, an update well not all bendix master cylinders are the same , NAPA only lists one kind but the depth is 2 1/4 inches Rock auto list four kinds and 1 5/8" that is what I needed .  The shop my car was in could have save everyone a lot of grief it they would have just measured  the stroke of the current power booster and the depth of the master cylinder finding is was short by 3/4 of an inch. The booster end adjustment is very critical for pedal position . In the manual they use a gauge but they do not state what the dimension should be and the only way to adjust it is to take it all apart .   Setting it 1 3/8 from the front end of the booster seemed to work.  Thanks again for all the help and advice. My problem now is it feels like manual brakes I do not get any help from the booster. How do I check to see if the booster is working OK or is it just a bad check valve. Trying to get the car to stop after the first few attempts I was pushing down on the brake with both feet as hard as I could to stop the car. I do not know if this over stretched the diaphragm. It appears that the Bendix boosters are not available  . You must send them in to get rebuilt. It that case I might as well put on a Delco booster and master cylinder. 

 

Any thoughts guys?

 

Thanks Erick

[EmTee]

How old are your brake hoses (esp. the rear one)?  I thought I had a bad booster until I replaced my hoses and voila -- regained power brake operation.  Restriction in the line(s) can cause a hard pedal.

Edited July 13, 2022 by EmTee (see edit history)

[Erick R]

all new lines, hoses and wheel cylinders so that is why I am a little confused. Thanks for the comments 

Erick

[Jim Cannon]

Erick, you need to confirm that your vacuum line check valve is sealing.

 

If it is, I suspect that the booster is bad.

 

 

Edited July 14, 2022 by Jim Cannon (see edit history)

[Erick R]

yep I agree that was my next step.  Thanks Jim.

[EmTee]

Yes, and verify that the booster itself holds vacuum using a hand vacuum pump.

[OldGerman]

Here I'm back again 2 1/2 years later with my dual master brake cylinder conversion.

I still have over breaking of the rear axle brakes, even with the valve decreasing the pressure (min. 70% pressure) to the rear.

I had this rear overbreaking already with the original but new Single Master Cylinder.

 

On my test drives with Dual MC I can't make the front brake / wheels locking.

This is good for steerabilty in emergency, but I beliefe the braking power in the front is way to low to stop the car safe in an emergency situation.

What I did:

- New Master (GM 1967 from POL) Did not use the Valve, can't make it fit below MC without interference to Power steering hoses.

- Rebuild Moraine Booster (Booster Dewey)

- MC was bench bleeded and system bleeded several times.

- Booster Push rod lenght was measured and adusted

- Front brake hoses have been replaced 6 years ago (CARS - oldbuickparts). Maybe they are to flexible ??

- Brake shoes/wheel cylinders replaced 6 years ago as well. Very low milage since then.

- Front drum diamter is not far away to the upper tolerance. 

- Brake adjustment if fine, no dragging to one side. Slight brake shoe dragging when turning wheels free.

 

- I have connected the REAR port of the MC to the original distribution block to feed the front brakes.

  I saw recommendations here to connect it the other way, but also found advice to connect it as I did.

 

Now I'm a little bit frustrated and unsure what to do next ?

- replace front brake hose ? Maybe using reinforced flex steel lines (if exists)

- replace the front brake lines (can't believe they are both restricted the same time )

- connect the MC outlets the other way (MC front/front - MC rear/rear)

 

any other idea ???

 

Thank you

 

[XframeFX]

Frank, definitely do not use the proportional valve that you have X'd .

 

As a matter of convention, the rear reservoir should only be used for a front circuit with master cylinders that has unequal size reservoirs as in disk brakes. In your case, the rear reservoir has the larger 1/4" fitting and can see why you chose to go opposite to standard convention with 4-wheel drum brakes. Should be good.

Strange, the fittings on your dual master cylinder with the smaller fitting on the front.

I used Bosch Brake Fluid. Strange how it is not classed DOT3, DOT4 or DOT5.1, just compatible to all except silicone DOT5.

 

Rather, something was already amiss before your conversion. Perhaps mismatched wheel cylinders? The front should be 1.125" and the rear 1". Any pinched/crushed tubing on the front circuit? I'm sure you checked all this already. Also, during the initial test drive, I back-up in reverse and apply the brakes several times to have the self adjusters do the final snugging up of the shoes. Simple I know, but sometimes it is just that.

 

Riviera63's (Bill) instructions above is straightforward. The only thing for 1963 if you want to keep the hydraulic brake light switch or convert to a 1964/65 switch at the pedal. I prefer Bill's use of the hydraulic switch even though it is just for the rear.

 

Maybe someone can chime in on anything I missed?

 

Good Luck!

 

 

 

Edited September 30, 2022 by XframeFX (see edit history)

[Jim Cannon]

The only way you might get the front wheels to skid before the rear wheels is to have a lot of weight in the trunk and a full tank of gas. The rear axle of this car is very light compared to the front with the massive engine. My rear wheels always skid first.  Buick put a small percentage of added braking in the front (56% front/44% rear), but not enough to do what you want to do. Once you confirm you have the correct wheel cylinders in the front, that's all you can do. It's not brake hoses, etc.  Confirm your auto adjusters are installed correctly (so that shoes expand then it click one click) and that they are free to turn.

 

You really should install the line from the front MC port to the front wheels, and rear to rear, because that is how GM did it. But because of the way this MC is designed, it really does not matter.

Edited September 30, 2022 by Jim Cannon (see edit history)