new dual master cylinder install

The Era of The Square Body Racing Comets
lavron
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Re: new dual master cylinder install

Post by lavron »

frankstein65 wrote:
Thu Apr 23, 2020 11:56 am
installed the new brace and the new m/c with booster. Wow.....I got brakes now.......great :D
Great to hear, brakes are one of the things I am trying to remedy in my build, never want it to fail to have a pedal again.

See Ya,
Mike
Mike's build thread
viewtopic.php?f=9&t=13058
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iglooman
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Re: new dual master cylinder install

Post by iglooman »

A/FX wrote:
Mon Apr 06, 2020 1:06 pm
My opinion:
Forget what the “mechanic” told you. First off you do not need power assist for you brake system. I installed front discs on my Cyclone in 1974, I used an unboosted Ford master cyl. designed for a factory installed manual disc/drum system. It worked perfectly. During the recent rebuild I have installed four wheel disc brakes from Baer using a un boosted dual master from Master Power Brakes in Charlotte NC. this system uses a balancing/ proportioning valve.
I would suggest you contact a company like Master Power Brakes for their recommendation. Cutting the shock tower for clearance is not the answer.
Jim

Great. I'm going to follow this. And get the brace too if I can find one.

iglooman
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Re: new dual master cylinder install

Post by iglooman »

A/FX wrote:
Mon Apr 06, 2020 1:06 pm
My opinion:
Forget what the “mechanic” told you. First off you do not need power assist for you brake system. I installed front discs on my Cyclone in 1974, I used an unboosted Ford master cyl. designed for a factory installed manual disc/drum system. It worked perfectly. During the recent rebuild I have installed four wheel disc brakes from Baer using a un boosted dual master from Master Power Brakes in Charlotte NC. this system uses a balancing/ proportioning valve.
I would suggest you contact a company like Master Power Brakes for their recommendation. Cutting the shock tower for clearance is not the answer.
Jim
So you mean like this one???
https://www.mpbrakes.com/pc_product_det ... 28DB04F02A

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SASSY
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Re: new dual master cylinder install

Post by SASSY »

Depending on the look you want under the hood you can also use one from a early Disc/drum manual brake Ranger.
Aluminum housing, plastic reservoir ports on the left side.
The important note is that the bore of the master on manual brakes is 15/16" which gives a good pedal/stroke feel relative to function.
Picture is reference only not necessarily the correct one.
https://www.google.com/aclk?sa=l&ai=DCh ... QCg&adurl=
I'd rather do it myself if it's done right or not,,,isn't that what hotrodding is all about

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iglooman
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Re: new dual master cylinder install

Post by iglooman »

:D :D :D :D

A/FX
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Re: new dual master cylinder install

Post by A/FX »

iglooman wrote:
Tue Jun 13, 2023 6:26 am
A/FX wrote:
Mon Apr 06, 2020 1:06 pm
My opinion:
Forget what the “mechanic” told you. First off you do not need power assist for you brake system. I installed front discs on my Cyclone in 1974, I used an unboosted Ford master cyl. designed for a factory installed manual disc/drum system. It worked perfectly. During the recent rebuild I have installed four wheel disc brakes from Baer using a un boosted dual master from Master Power Brakes in Charlotte NC. this system uses a balancing/ proportioning valve.
I would suggest you contact a company like Master Power Brakes for their recommendation. Cutting the shock tower for clearance is not the answer.
Jim
So you mean like this one???
https://www.mpbrakes.com/pc_product_det ... 28DB04F02A
The reply I initially made to this thread is now over 3 years old. Since that time I have issues with the Master Power Brakes system. The master cylinder and adjustable pedal rod have worked just fine, the issue was with the combination valve that was supplied by MPB. (Keep in mind I am using Baer Brakes on all four corners) When the car was first finished and I was sorting out all the systems the brakes were the most concerning, I was unable to obtain a “ good pedal”. I went through every part of the braking system, looking for the obvious, but nothing was found. The issue was the brakes would not stop the car no matter how hard the pedal was pressed, it slowed down but I could not make a deliberate stop. I bled the system using multiple methods, vacuum, pressure, foot pumping, etc. the system still seemed to have air trapped somewhere. Finally after much frustration I removed the combination valve and replaced ot with an adjustable proportioning valve and a 2lb residual check valve in the front and rear supply lines.
Problem solved! It took a couple of test drives to dial in the proportioning valve but after that the brakes worked as they should.
I now think that there is no way an over the counter valve like is supplied with the MPB kit can be accurate for every type of application. The adjustable valve has the capability of being able to be dialed into each individual application. (Total weight, balance weight, tire size(s),etc.)
Jim
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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kevinshi
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Re: new dual master cylinder install

Post by kevinshi »

A/FX wrote:
Tue Jun 13, 2023 2:13 pm
...I bled the system using multiple methods, vacuum, pressure, foot pumping, etc. the system still seemed to have air trapped somewhere. Finally after much frustration I removed the combination valve and replaced ot with an adjustable proportioning valve and a 2lb residual check valve in the front and rear supply lines. Problem solved!
Augh, Jim your story sounds exactly like what I have been suffering through for the last 12-18 months. I feel like I am chasing ghosts. I have blown out multiple MCs re-bleeding my system. I got the pressure bleeder as well - mine installs hold 15 PSI for a week (no leaks man). If I had hair it would be pulled out.

No matter how hard I try the best I can do is a soft pedal that feels like it needs pumping - like there is air... but there is no dang air in there.

Would you kindly post which adjustable proportioning valve and a 2lb residual check valves you used?

I am not using the Master Power Brakes system but rather one from ABS Brakes system. I think they are very similar - but not exactly the same.
Thanks,
kevin
1965 Caliente Convertible
5H25A525287 (76DM6204L5416)

A/FX
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Re: new dual master cylinder install

Post by A/FX »

Have you tried bleeding the system using the pedal method and the vacuum method at the same time? That is what it took to get the last air bubble out of mine. Now I have a pedal just like the way I prefer tushy, nice and firm!


This is the proportioning valve I used. You could easily use a Willwood unit in its place:

https://www.ebay.com/itm/394443715731?c ... i1EALw_wcB

I used two of these, one for the front and rear discs:
https://www.wilwood.com/MasterCylinders ... =260-13706
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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FuzzyDriver
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Re: new dual master cylinder install

Post by FuzzyDriver »

Wilwood says to use 10 psi valves for drum brakes. Is this only when you install a dual master cylinder? Or why would stock Comet's not need one? Or do they have something already built in?
OK...so she might need a little work.Image

A/FX
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Re: new dual master cylinder install

Post by A/FX »

FuzzyDriver wrote:
Sun Jul 09, 2023 2:31 am
Wilwood says to use 10 psi valves for drum brakes. Is this only when you install a dual master cylinder? Or why would stock Comet's not need one? Or do they have something already built in?
10lb for drums and 2lb for discs. Some master cylinders had built in residual valves. If you have 4 drums just source a dual master that has the same bore as your stock master and is spec’d for drum brakes. My application is for the 4 wheel Baer brakes I have on my Cyclone.
Jim
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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Caveman49
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Re: new dual master cylinder install

Post by Caveman49 »

Hey Jim, if you don’t mind, how did you dial in your adjustable proportioning valve. The one I have on the 66 came with the kit I got from Dan at chockostang, it seems to do ok and car stops good, can’t get em to lock up at all. I guess that’s a good thing, but brakes sure aren’t like power brakes I’m used to.
I have disc front, drum rear, no 2 or 10 lb check valves, yet 😁
Thanks for all your input, very helpful.
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Motor Safe,
Lee

A/FX
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Re: new dual master cylinder install

Post by A/FX »

Caveman49 wrote:
Sun Jul 09, 2023 9:10 am
Hey Jim, if you don’t mind, how did you dial in your adjustable proportioning valve. The one I have on the 66 came with the kit I got from Dan at chockostang, it seems to do ok and car stops good, can’t get em to lock up at all. I guess that’s a good thing, but brakes sure aren’t like power brakes I’m used to.
I have disc front, drum rear, no 2 or 10 lb check valves, yet 😁
Thanks for all your input, very helpful.
There needs to be a residual valve plumbed into each line. If the master has them internally then in line units are not needed. The adjustable proportioning valve is plumbed into the rear brake line where it leaves the master cylinder. Leave the valve fully open for a low speed test drive, apply the brakes lightly to see which end grabs first. The valve works opposite a normal water faucet, all the way open is no proportioning, turning the knob in lessens the pressure to the rear brakes, which allows the front brakes to activate sooner. You want the front brakes to grab slightly before the rear, if the rear brakes are applied before the front the car may try to swap ends. After you do slow stops and are confident that the rear brakes are not being applied before the front try a medium speed panic stop. Work your way up to a faster stop. Driving and adjusting is the only way to balance the system.
Jim
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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kevinshi
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Re: new dual master cylinder install

Post by kevinshi »

A/FX wrote:
Sat Jul 08, 2023 7:48 pm
Have you tried bleeding the system using the pedal method and the vacuum method at the same time? That is what it took to get the last air bubble out of mine.
No, I have not... I didn't realize there was such a procedure. I have avoided stepping on the pedal when the pressure bleeder is strapped onto the MC - I have been worried that might force fluid through the seal on the MC or damage the hand pump. (I am using the Motive Products hand pump with early American MC seal - is that what you have used?).

What is your process for doing them at the same time?
Thanks,
kevin
1965 Caliente Convertible
5H25A525287 (76DM6204L5416)

A/FX
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Re: new dual master cylinder install

Post by A/FX »

kevinshi wrote:
Sun Jul 09, 2023 11:26 am
A/FX wrote:
Sat Jul 08, 2023 7:48 pm
Have you tried bleeding the system using the pedal method and the vacuum method at the same time? That is what it took to get the last air bubble out of mine.
No, I have not... I didn't realize there was such a procedure. I have avoided stepping on the pedal when the pressure bleeder is strapped onto the MC - I have been worried that might force fluid through the seal on the MC or damage the hand pump. (I am using the Motive Products hand pump with early American MC seal - is that what you have used?).

What is your process for doing them at the same time?
I have used a Motive pump, it works on some applications but I did not have luck using it on the Comet. I also have a vacuum bleeder (info sheet attached) I have used it in other vehicles and it works fine. On the Comet I used the vacuum bleeder in tandem with a helper pumping the brakes as normally done. I use and recommend Speed Bleeders, they are cheap and work exceptionally well, and allow a one person bleeding when using the pump the pedal method. http://www.speedbleeder.com/
I fabricated my own master cylinder adapter for the Motive unit, it attaches to the master with a stud/ clamp system so it should never leak under pressure from the Motive pump.
Jim

Here is the adapter:
Image

And the vacuum bleeder:
Image
‘64 Cyclone/ Boss 302,quads,4spd, Winters 9”

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Caveman49
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Re: new dual master cylinder install

Post by Caveman49 »

A/FX wrote:
Sun Jul 09, 2023 10:47 am
Caveman49 wrote:
Sun Jul 09, 2023 9:10 am
Hey Jim, if you don’t mind, how did you dial in your adjustable proportioning valve. The one I have on the 66 came with the kit I got from Dan at chockostang, it seems to do ok and car stops good, can’t get em to lock up at all. I guess that’s a good thing, but brakes sure aren’t like power brakes I’m used to.
I have disc front, drum rear, no 2 or 10 lb check valves, yet 😁
Thanks for all your input, very helpful.
There needs to be a residual valve plumbed into each line. If the master has them internally then in line units are not needed. The adjustable proportioning valve is plumbed into the rear brake line where it leaves the master cylinder. Leave the valve fully open for a low speed test drive, apply the brakes lightly to see which end grabs first. The valve works opposite a normal water faucet, all the way open is no proportioning, turning the knob in lessens the pressure to the rear brakes, which allows the front brakes to activate sooner. You want the front brakes to grab slightly before the rear, if the rear brakes are applied before the front the car may try to swap ends. After you do slow stops and are confident that the rear brakes are not being applied before the front try a medium speed panic stop. Work your way up to a faster stop. Driving and adjusting is the only way to balance the system.
Jim
Thanks Jim!
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Motor Safe,
Lee

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