Disc Disc Brake System Components?

I just changed directions with my rear end on my 40 and am going to be using rear disc brakes. I have a corvette type MC and am going to use hydra boost instead of a vacuum booster. I understand I need a 2psi residual valve in the front line, and a metering valve in the front line. The rear line needs an adjustable proportioning valve. I'm assuming the rear needs a 2psi residual valve as well? My front calipers are GM metrics I'm pretty sure and the rear are going to be from an Explorer. Does this sound correct, or what would you do differently? Thanks in advance for the help. I'd like to build the system once and not have to go back and do it again. :LOL:

Where is your master cylinder located? With HydraBoost I'm assuming it's firewall mounted? My understanding is that you only need the 2# residual valves for an under floor master, where the calipers are higher than the master.

Most masters already have the residual valves in the fittings where the lines attached and are to hold the shoes/pads in place near the discs so the pedal throw is consistend and short---------

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Originally Posted by rspears

Where is your master cylinder located? With HydraBoost I'm assuming it's firewall mounted? My understanding is that you only need the 2# residual valves for an under floor master, where the calipers are higher than the master.

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The master/hydra boost will be under the floor on the frame.

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Originally Posted by jerry clayton

Most masters already have the residual valves in the fittings where the lines attached and are to hold the shoes/pads in place near the discs so the pedal throw is consistend and short---------

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Jerry, are they built into the housing or inside between the bore port and line outlets? Maybe my master cylinder has them already?

http://www.clubhotrod.com/photopost/...VC-626F_1_.JPG

This is the Mustang hydraboost and master mounted under floor in a 32 ford

Make fun of me if you must, but what is a hydraboost?

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Originally Posted by 53 Chevy5

Make fun of me if you must, but what is a hydraboost?

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in a nutshell....Hydroboost Brake Assist Booster and Function

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Originally Posted by 40FordDeluxe

I just changed directions with my rear end on my 40 and am going to be using rear disc brakes. I have a corvette type MC and am going to use hydra boost instead of a vacuum booster. I understand I need a 2psi residual valve in the front line, and a metering valve in the front line. The rear line needs an adjustable proportioning valve. I'm assuming the rear needs a 2psi residual valve as well? My front calipers are GM metrics I'm pretty sure and the rear are going to be from an Explorer. Does this sound correct, or what would you do differently? Thanks in advance for the help. I'd like to build the system once and not have to go back and do it again. :LOL:

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Ryan, this sounds pretty similar to the setup I created for my '37 but it's been a while since I've looked at it. I used the SN95 Mustang rear brake conversion on my 9" rear and have GM calipers on the front, Corvette MC with 7" booster, but if I like the hydraboost conversion on my truck, I think I'll add hydaboost to the '37. I have 2# residual valves front & rear plus a proportioning valve on rear line.

Ryan, make sure that the explorer and gm metrics are similar volume, if they are not you won't collapse the larger volume calipers and you will only use the smaller, all calving, residual, proportioning and such limit pressure not volume, that's controlled by the mc itself and cannot be regulated once pressed. Master power told me this long ago, same reason you can't put wilwoods on the back and gms on the front, on drum backs and disc fronts the mc is metered differently by its piston i was told, this the reason the mc reservoir has two different sizes. I am not an expert but just make sure and check, a lot of rods running around with rear discs not working due to large volume calipers back there!

Here's an image I used to help with mine...

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Originally Posted by jerry clayton

http://www.clubhotrod.com/photopost/...VC-626F_1_.JPG

This is the Mustang hydraboost and master mounted under floor in a 32 ford

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Man, that is a tiny pic! :LOL:

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Originally Posted by Matthyj

Ryan, make sure that the explorer and gm metrics are similar volume, if they are not you won't collapse the larger volume calipers and you will only use the smaller, all calving, residual, proportioning and such limit pressure not volume, that's controlled by the mc itself and cannot be regulated once pressed. Master power told me this long ago, same reason you can't put wilwoods on the back and gms on the front, on drum backs and disc fronts the mc is metered differently by its piston i was told, this the reason the mc reservoir has two different sizes. I am not an expert but just make sure and check, a lot of rods running around with rear discs not working due to large volume calipers back there!

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Hmm, I will check it out and see if I can figure the volume of each. I wonder if you could use a different MC to accommodate if one caliper is larger than the other. I have seen some other GM disc disc MC's that had a large and small reservoir. I think they are on the newer vans we have at work. Just a thought.

Here is a little info I figured out when I was going to use the Explorer brakes on my project that may help.

Ford Expedition calipers have the same bolt pattern as the Explorer's. They have a slightly larger bore. It's only about 1/8", but it will make a difference in clamping pressure and bring you closer in size to the GM metrics.

Also, the Expedition pads are so close in size to the Explorer's, that they could easily be made to fit. They have a larger friction surface. The pads will almost fit as is. The Explorer rotors have enough width to just accept the Expedition pads. This will increase the "swept area" of the brakes and increase friction as well as reducing pad wear.

I changed over to the SVT Mustang brakes on my project and never got around to making the swap, but have the parts in hand. I'll put them on my 46 when I finally get around to it. I feel like I could use a little more brake power on it because it's so heavy.

Just something to think about.

http://www.clubhotrod.com/photopost/...VC-626F_1_.JPG

Well this is same pic but larger---these are located in my gallery about a 32 ford build I did for a customer with 540 bbc and hilborn stack fuel injection converted to electronics---------if you want to brosse thru them just click the camera in my avator-------this is on page 5


system was from late model Mustang-has all the relief, proportioning, etc valves needed---------

Ryan,
You asked about the location of the "internal" residual valves. If provided, they are behind the tube seat insert, along with a little spring. To see if you have them take a paper clip or similar small diameter object (butt end of a small drill bit works good) and slowly push it into the output ports. If you feel a spongy resistance, you are pushing against a residual. If none are present, the object will easily go into the master bore.

There is a lot of info published about rebuilders not installing internal residual valves when they refurbish cores, because they pretty much disappeared from use with disc/disc, master on firewall applications. Here's a crappy old picture that shows where they reside, if installed. People removed them by putting a big sheet metal screw gently into the brass tube seat, gently prying it out, and then pushing it back in place. Doesn't damage the seating surface if done carefully....

Attachment 67394

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Originally Posted by Hotrod46

Here is a little info I figured out when I was going to use the Explorer brakes on my project that may help.

Ford Expedition calipers have the same bolt pattern as the Explorer's. They have a slightly larger bore. It's only about 1/8", but it will make a difference in clamping pressure and bring you closer in size to the GM metrics.

Also, the Expedition pads are so close in size to the Explorer's, that they could easily be made to fit. They have a larger friction surface. The pads will almost fit as is. The Explorer rotors have enough width to just accept the Expedition pads. This will increase the "swept area" of the brakes and increase friction as well as reducing pad wear.

I changed over to the SVT Mustang brakes on my project and never got around to making the swap, but have the parts in hand. I'll put them on my 46 when I finally get around to it. I feel like I could use a little more brake power on it because it's so heavy.

Just something to think about.

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Thanks for the info! I did notice the explorer calipers look small. I will make this swap. This should help keep the calipers closer to the same size as the gm metric ones on the front.

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Originally Posted by rspears

Ryan,
You asked about the location of the "internal" residual valves. If provided, they are behind the tube seat insert, along with a little spring. To see if you have them take a paper clip or similar small diameter object (butt end of a small drill bit works good) and slowly push it into the output ports. If you feel a spongy resistance, you are pushing against a residual. If none are present, the object will easily go into the master bore.

There is a lot of info published about rebuilders not installing internal residual valves when they refurbish cores, because they pretty much disappeared from use with disc/disc, master on firewall applications. Here's a crappy old picture that shows where they reside, if installed. People removed them by putting a big sheet metal screw gently into the brass tube seat, gently prying it out, and then pushing it back in place. Doesn't damage the seating surface if done carefully....

Attachment 67394

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Thanks for that Roger. I will check my MC to see if it has them. There is a really good chance it does not have them.

If you have access to milling machine, the caliper mounting brackets could be opened up a little to take the Expedition pads. That was the route I was going to take so that off the shelf pads could be used. As I recall, the Expedition pad backing plates are a tiny bit longer than the Explorer pads.

A couple of minutes with a grinder would modify the pads if you don't have a mill.

The calipers should fit with no mods and the Explorer pads could be used if you wanted.

Strange that Ford would make the rotor with a lot of wasted width. True enough, it's toward the inside of the friction area, but it's there.

It's possible that the Expedition caliper brackets and rotors could be used, but I never got around to checking that.

The Expedition rotors are around 11"-12", so wheels would have to be 16" to 17". They are also 6 lug, so they would have to be redrilled. There may not be enough room to do that.

Check everything out pretty good because I only bought the parts and did a few rough measurements. I'm confident the caliper and pad swap will work, though.