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Front Disc conversion with scarebird brackets


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1 hour ago, RivNut said:

Thanks, I'll take a look at mine and see if I can find the numbers. Which calipers were your brackets designed for?

 

 

Scarebird parts list.jpg

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Carl,

 

   To try & answer some of your questions.

1st. the front to rear line is 3/16ths. & the 1" master provides enough fluid & pressure to operate the rear brakes properly.

 

2nd. is the disc brake area is larger BUT the amount of fluid nec. to activate such is actually less because not as much fluid is required to activate the front calipers. This is because the pads are ALWAYS somewhat in contact with the rotor because of atmospheric pressure of 14.7lbs. The retracting part of the calipers is that the square cut seal which comes in contact with the caliper piston kinda bends outwards with the application of the brake pedal & bends back when you release the brake pedal releasing the pads contact with the rotor.

 

3rd. You MUST use a dual master when using disc brakes.  The safety aspect is the brake system is now split into two parts, front & rear.  So IF one system fails you have the safety of the other. Hopefully. The actual braking affect would be a lower/harder pedal & longer stopping distance, BUT you have something instead of NOTHING or just relying on the emergency brake.

 

    Now when mounting a dual master set-up the larger volume reservoir is for the front disc brakes because as the front pads wear fluid takes their place. 

 

   On a universal proportioning valve it does the same thing as a metering block, except it takes up much more space. IF you mount it as suggested usually the washer tank has to be removed or re-located. Has MUCH more fabrication as far as the front & rear lines go. In the tight confines of the recommended location you HAVE to be able to make your own lines.  IF you haven't done this before it can be aweful frustrating trying to learn how to do fabrication & flaring the ends of the tubing & bend the lines in the confines of such a tight line configuration without kinking the lines. 

    On the other hand a metering block really only requires one line to be made from the master to the metering block..  IF you are not comfortable doing this you can take measurements & go to a shop that will make the line nec. You MUST remember the line coming from the master to the metering valve needs to have a couple of coils in it as the firewall & the frame of the vehicle move seperately. The block can go in the same place as the original distribution block on the frame of the car. Which includes the master connection the two lines going to the front brakes & one line to the rear. Four conections in total. So one line coming from the master to the metering block & two lines going out to the front brakes which in MOST cases can be

re-used. 

    Now for the rear all you need to do is connect the rear line to the master with a line connector & some tubing. You don't have to worry about coiling the rear line as there is plenty of the rear line to allow movement WITHOUT worrying about deflection of the rear line to flex so much that it will break.

Hopefully I've explained this clearly enough to be understood.

 

Tom T.

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Seems like a lot of farting around just to be able to make repeated panic stops.

 

I will never be convinced there is value to gathering up a collection of over the counter parts that appear to fit together.

 

Just not my style counter.

Overthecounter.jpg.8cdcc434e34d2adc5ef61767301d5d40.jpg

 

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On 3/7/2021 at 2:09 PM, telriv said:

Carl,

 

   To try & answer some of your questions.

1st. the front to rear line is 3/16ths. & the 1" master provides enough fluid & pressure to operate the rear brakes properly.

 

2nd. is the disc brake area is larger BUT the amount of fluid nec. to activate such is actually less because not as much fluid is required to activate the front calipers. This is because the pads are ALWAYS somewhat in contact with the rotor because of atmospheric pressure of 14.7lbs. The retracting part of the calipers is that the square cut seal which comes in contact with the caliper piston kinda bends outwards with the application of the brake pedal & bends back when you release the brake pedal releasing the pads contact with the rotor.

 

3rd. You MUST use a dual master when using disc brakes.  The safety aspect is the brake system is now split into two parts, front & rear.  So IF one system fails you have the safety of the other. Hopefully. The actual braking affect would be a lower/harder pedal & longer stopping distance, BUT you have something instead of NOTHING or just relying on the emergency brake.

 

    Now when mounting a dual master set-up the larger volume reservoir is for the front disc brakes because as the front pads wear fluid takes their place. 

 

   On a universal proportioning valve it does the same thing as a metering block, except it takes up much more space. IF you mount it as suggested usually the washer tank has to be removed or re-located. Has MUCH more fabrication as far as the front & rear lines go. In the tight confines of the recommended location you HAVE to be able to make your own lines.  IF you haven't done this before it can be aweful frustrating trying to learn how to do fabrication & flaring the ends of the tubing & bend the lines in the confines of such a tight line configuration without kinking the lines. 

    On the other hand a metering block really only requires one line to be made from the master to the metering block..  IF you are not comfortable doing this you can take measurements & go to a shop that will make the line nec. You MUST remember the line coming from the master to the metering valve needs to have a couple of coils in it as the firewall & the frame of the vehicle move seperately. The block can go in the same place as the original distribution block on the frame of the car. Which includes the master connection the two lines going to the front brakes & one line to the rear. Four conections in total. So one line coming from the master to the metering block & two lines going out to the front brakes which in MOST cases can be

re-used. 

    Now for the rear all you need to do is connect the rear line to the master with a line connector & some tubing. You don't have to worry about coiling the rear line as there is plenty of the rear line to allow movement WITHOUT worrying about deflection of the rear line to flex so much that it will break.

Hopefully I've explained this clearly enough to be understood.

 

Tom T.

 

Tom

 

Very good writeup but do have a couple more questions.

 

Master cylinder/power Booster

 I was planning on  keeping with the Rivera line and use the 67 disc/drum dual reservoir master cylinder. Because the 67 master cylinder is 1 1/8 bore and the 64 is 1" bore, I will also purchase the power booster as well. I thought I read someway that the power booster has the same firewall bolt pattern as the 64. Hopefully that is true. Going from a 64 1" bore to a 67 1 1/8" bore master cylinder I will lose some pressure but can't see it being enough to affect rear brake performance.  I did confirm also that the 76 Cadillac calipers that the bracket was made for does use a 1 1/8" bore master cylinder so there should be no front performance issue there. 

1) Any thoughts on my assumtions?

2) I have read where the drum brake like to have a preload of 10LBS. With using a metering block where the lines are directly plumbed from the master cylinder to the rear cylinders, would there be a need for a residual pressure valve or does the master cylinder keep a preload on the rear brakes?

3) With going to a 1 1/8 bore master cylinder, would that necessitate me increasing the rear backlines to 1/4" ? Also not sure if going to a larger line would cause any sealing issues at the rear wheel cylinders.

 

Brake valves

From reading your writeup and doing metering valve vs proportioning valve vs combination valve google writeups , aside from the size penalty of the proportioning valve, the one thing I would lose by not using a proportion valve is a brake light indication that one of the circuits (front or rear) has failed. I would think that would be apparent at the brake pedal. The only other thing I may lose is under extreme braking the proportioning or combination valve is suppose to help with rear wheel lockup. However, with me going from a 1" bore on the 64 to a 1 1/8" bore from the 67 master cylinder, that should help with rear wheel lock up under those conditions. 

4) Am I kind of on the right track with my thought process?

 

Thanks again for everyone's help

Carl

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Posted (edited)
On 3/8/2021 at 1:21 PM, 60FlatTop said:

Seems like a lot of farting around just to be able to make repeated panic stops.

 

I will never be convinced there is value to gathering up a collection of over the counter parts that appear to fit together.

 

 

 

 

I guess it is based on comfort level and/or maintaining originality. 

 

Carl

Edited by Ckerch (see edit history)
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http://www.1964buick.com/resto_logs/dual_master/1964_Wildcat_dual_master_cylinder.htm

 

I had found this site when I converted my single MC to dual. He goes into detail about the 67 booster not fitting.

 

When I did my MC conversion, I also replaced all the lines with stainless steel kit, and used SS lines for a 65 chevy for between the MC and distribution block. It might be worthwhile to see if you can find some that will fit whatever block you use. For my drum car, I tried using the 65 chevy block, but it put the right side line right into the steering box. Went back to the original 64 block, and plugged the rear port. Then i used a angle adapter to run the line straight down from the MC to the frame, then to the rear. I can post pics if it helps.

Edited by jsgun (see edit history)
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23 hours ago, jsgun said:

http://www.1964buick.com/resto_logs/dual_master/1964_Wildcat_dual_master_cylinder.htm

 

I had found this site when I converted my single MC to dual. He goes into detail about the 67 booster not fitting.

 

When I did my MC conversion, I also replaced all the lines with stainless steel kit, and used SS lines for a 65 chevy for between the MC and distribution block. It might be worthwhile to see if you can find some that will fit whatever block you use. For my drum car, I tried using the 65 chevy block, but it put the right side line right into the steering box. Went back to the original 64 block, and plugged the rear port. Then i used a angle adapter to run the line straight down from the MC to the frame, then to the rear. I can post pics if it helps.

 

Nice job and excellent write up!!

 

It seems that the ACdelco master cylinder you used isn't available anymore (at least I can't find it online).  Looking at other 67 Wildcat Disc/Drum master cylinders, it looks like those are 1 1/8" bore and our Power Booster is made for a 1" bore.

Did you have to make any modifications to fit the master cylinder into the 64 Power Booster?  

Also, how did you determine between Bendix or Morane  capable master cylinder and if it was shallow piston hole?

 

The block that you used, did it have any metering function to it or was a straight through block?

 

Thanks,

Carl

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On 3/11/2021 at 4:32 PM, Ckerch said:

 

Nice job and excellent write up!!

 

It seems that the ACdelco master cylinder you used isn't available anymore (at least I can't find it online).  Looking at other 67 Wildcat Disc/Drum master cylinders, it looks like those are 1 1/8" bore and our Power Booster is made for a 1" bore.

Did you have to make any modifications to fit the master cylinder into the 64 Power Booster?  

Also, how did you determine between Bendix or Morane  capable master cylinder and if it was shallow piston hole?

 

The block that you used, did it have any metering function to it or was a straight through block?

 

Thanks,

Carl

Carl, Sorry, it's not my site. I found it some time ago when I was trying to figure out my dual chamber MC conversion. I kept drums, just converted to dual MC using a 67 drum/drum MC. I still have my stock 64 booster. I don't know of a way to externally tell which brand the booster is, but when you pull the MC, it'll be very obvious if it has the shallow or deep hole. The plunger coming out of the booster will be as long as the studs for the MC. I bought the wrong one at first, the plunger hole is right at the top of the assembly. The 67 MC fit perfectly, zero issue mating to the booster. The brake lines were a challenge, but I went with stainless lines so they were difficult to bend. I bought a pair of coiled lines for a 65 Chevy, and the front line went into the original 64 junction block. I put a plug in the port going to the rear line in the block. The rear line from the MC went into a 90 degree angle fitting, and then into the 64 stainless rear line. I can get fitting sizes listed if you want.

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64 MC installed.jpg

 

67 MC, 65 Chevy brake lines (not bolted down yet), 64 original booster. Lines had to be "interwoven" together to get them off the fenderwell. Took a lot of bending to decrease the radius of the circle too. It was not a direct bolt in. 

 

65 lines for dual MC.jpg

 

65 Chevy MC lines meeting stock junction block for front, rear line on right going into 90 degree angle and adapter. 

 

64 booster cup.jpg

 

This is the elusive "cup seal" that fits between the MC and the booster. Without this there is a constant vacuum leak and no power brakes. P.O. drove this car over 200 miles with no power brakes and rough running engine. I bought it from "Booster Dewey Exchange", also known as "Power Brake Booster Exchange". It isn't on their site, had to call them. $50 counting shipping. Only source for them, as far as I know.

Edited by jsgun (see edit history)
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